1 Trastornos del metabolismo de las biopterinasDra. Daniela Muñoz Ch. Dra. Diane Vergara G. Neuróloga Infantil Becada Neurología Pediátrica 24 enero 2014

2 Introducción Neurotransmisor Clasificación bioquímicaSe sintetiza en la neurona Se presenta en la terminal presináptica y se libera en cantidades suficientes para ejercer una acción determinada en la neurona postsináptica Administrado en cantidades suficientes reproduce la acción de la molécula endógena Existe un mecanismo específico para eliminarse del espacio sináptico Neurotransmisor Clasificación bioquímica Aminas biógenas: catecolaminas e indolaminas Acetilcolina Aminoácidos: GABA, glut, NAA, glicina, serina Purinas: AMP, ADP, ATP Neuropéptidos Los NT pueden agruparse según la ‘familia bioquímica’ a la que pertenecen en: 1. Aminas biógenas: catecolaminas e indolaminas (serotonina). 2. Acetilcolina. 3. Aminoácidos: GABA (ácido γ-aminobutírico), glutamato, N-acetil-aspartato, glicina y serina. (El GABA y la glicina son aminoácidos inhibitorios; el glutamato y el aspartato son excitatorios.) 4. Purinas: AMP (adenosina monofosfato), ADP (adenosina difosfato) y ATP (adenosina trifosfato). 5. Neuropéptidos. Kurian MA, et al. The monoamine neurotransmitter disorders: an expanding range of neurological syndromes. Lancet Neurol 2011; 10: 721–33 García-Cazorla A et al. Errores congénitos de los neurotransmisores en Neuropediatría. Rev neurol 2005; 41:

3 Enfermedades de neurotransmisores en pediatríaGrupo de trastornos neurometabólicos hereditarios atribuibles a una alteración primaria del metabolismo de neurotransmisores (NT) o su transporte Grupo en crecimiento, requiere métodos diagnósticos especiales Primera descripción: convulsiones que responden a piridoxina (1954) En los últimos años expansión del conocimiento respecto las bases moleculares de estas enfermedades, su expresión fenotípica y opciones de tratamiento Síntomas determinados por el tipo y severidad del trastorno Lo central: manifestaciones neurológicas Importante alto índice de sospecha: tratamiento These compounds are produced in relatively short synthetic pathways from precursors that derive from the major carbohydrate substrates of intermediary metabolism. There are enzymatic pathways that degrade neurotransmitters and are important for the control of their concentrations within the neuron and for their inactivation Symptoms are determined by the type and severity of the disorder and are dominated by neurological features, including developmental delay, pyramidal and extrapyramidal motor disorders, epilepsy, autonomic dysfunction, and neuropsychiatric symptoms. Overall, the clinical phenotype mimics that of many other neurological disorders and, therefore, misdiagnosis or diagnostic delay are common. Onset can occur at any age but is most frequently in infancy or early childhood. A diferencia de muchos otros ECM, los causados por defecto en los NT no presentan afectación extraneurológica y, generalmente, los exámenes metabólicos en suero y orina son normales, mientras que en el líquido cefalorraquídeo (LCR) muestran un perfil de metabolitos característico Pearl PL, et al. Diagnosis and Treatment of Neurotransmitter Disorders. Curr Treat Options Neurol Nov;8(6):441-50 Pons R. The phenotypic spectrum of paediatric neurotransmitter diseases and infantile parkinsonism. J Inherit Metab Dis (2009) 32:321–332 Campeau PM, et al. Neurotransmitter diseases and related conditions. Mol Genet Metab Nov;92(3):189-97 Kurian MA, et al. The monoamine neurotransmitter disorders: an expanding range of neurological syndromes. Lancet Neurol 2011; 10: 721–33

4 Enfermedades de neurotransmisores en pediatría: grupos clásicosEpilepsia severa precoz (glicina) Epilepsia, trastorno del lenguaje expresivo, trastornos psiquiátricos (GABA) Vía de aminoácidos Amplio espectro de manifestaciones Monoaminas o aminas biógenas These compounds are produced in relatively short synthetic pathways from precursors that derive from the major carbohydrate substrates of intermediary metabolism. There are enzymatic pathways that degrade neurotransmitters and are important for the control of their concentrations within the neuron and for their inactivation Pons R. The phenotypic spectrum of paediatric neurotransmitter diseases and infantile parkinsonism. J Inherit Metab Dis (2009) 32:321–332

5 Clasificación Pearl PL, et al. Diagnosis and Treatment of Neurotransmitter Disorders. Curr Treat Options Neurol Nov;8(6):441-50

6 TRASTORNOS DE LAS MONOAMINAS

7 Trastornos de las aminas biógenas o monoaminasVía incluye síntesis y catabolismo de Catecolaminas: dopamina, Noradrenalina (NA) y adrenalina Indoleamina: serotonina Son NT importantes en SNC y SNP, también funcionan como hormonas Desde tirosina Desde triptófano Pons R. The phenotypic spectrum of paediatric neurotransmitter diseases and infantile parkinsonism. J Inherit Metab Dis (2009) 32:321–332 Pearl PL. Monoamine neurotransmitter deficiencies. Handb Clin Neurol. 2013;113:

8 Trastornos de las monoaminas: vía dopaminérgicaManifestaciones extrapiramidales Neuronas dopaminérgicas (mesencéfalo: SNc, área tegmental ventral) Vía nigroestriatal Vía mesolímbica Vía mesocortical Control del movimiento voluntario Cognición y comportamiento Dopaminergic neurons are located mainly in the substantia nigra pars compacta (with projections to the striatum via the nigrostriatal pathway), ventral tegmental area of the midbrain (with mesocorticolimbic projections to the nucleus accumbens, hippocampus, and other corticolimbic structures), and the hypothalamus (with projections to the pituitary gland via the tuberoinfundibular pathway).16 Various important physiological functions, such as control of voluntary locomotion, cognitive processes (including attention and memory), neuro endocrine secretion (prolactin), and control of motivated behaviours, such as emotion, aff ect, and reward mechanisms, therefore, have been attributed to dopamine También en hipotálamo (función vegetativa y hormonal) Pons R. The phenotypic spectrum of paediatric neurotransmitter diseases and infantile parkinsonism. J Inherit Metab Dis (2009) 32:321–332

9 Trastornos de las monoaminas: vía serotoninérgicaNeuronas serotoninérgicas (núcleos del rafe) Proyección difusa al cerebro y médula espinal Control apetito, sueño, memoria y aprendizaje, T° corporal, ánimo, comportamiento sexual, función cardiovascular, contracción muscular, homeostasis Serotonergic neurons principally arise from the midbrain dorsal and ventral raphe nuclei, which are centred on the reticular formation, with widespread projections to several supratentorial cortical areas—the supplementary motor area, premotor cortex, and primary motor cortex—and infratentorially to the cerebellum and spinal cord. Serotonergic innervation of the basal ganglia is sparse in the caudate nucleus, moderate in the putamen, substantia nigra, and ventral tegmental area, and dense in the globus pallidus.23 This innervation pattern implicates a role for serotonin in motor control, and is supported by diminished serotoninergic motor responses and increased sensitivity to serotoninergic agonists in genetically dystonic rats.24 In human beings, serotonin syndrome, which has major motor features, including dystonia, arises from iatrogenic increases of synaptic serotonin or stimulation of serotoninergic receptors.25 Serotonin is also thought to play a part in autonomic control of respiration and temperature and in mood. También en pared de intestino y vasos sanguíneos Pons R. The phenotypic spectrum of paediatric neurotransmitter diseases and infantile parkinsonism. J Inherit Metab Dis (2009) 32:321–332

10 Trastornos de las monoaminas: vía noradrenérgica y adrenérgicaNeuronas noradrenérgicas (locus ceruleus) Proyección difusa a corteza, cerebelo y médula espinal Funciones atención, ánimo, sueño y cognición En SNP actúa en neuronas postganglionares del SNS Médula Adrenal Adrenalina Hormona de estrés Pons R. The phenotypic spectrum of paediatric neurotransmitter diseases and infantile parkinsonism. J Inherit Metab Dis (2009) 32:321–332

11 Metabolismo de las monoaminasL-DOPA and 5-hydroxytryptophan are then converted to dopamine and serotonin, respectively. Both of these reactions are catalyzed by the same enzyme, aromatic L-amino acid decarboxylase (AADC), formerly called dopa-decarboxylase La biosíntesis de estos NT parte de los aminoácidos tirosina (vía dopaminérgica) y triptófano (vía serotoninérgica), en reacciones catalizadas por diferentes enzimas (Fig. 1) Algunas de estas enzimas necesitan la presencia de coenzimas para su correcto funcionamiento, y la más importante es la tetrahidrobiopterina (BH4). La BH4 es el cofactor natural no sólo de las enzimas tirosina hidroxilasa (síntesis de levodopa, precursor de dopamina) y triptófano hidroxilasa (síntesis de 5-hidroxitriptófano, precursor de serotonina), sino también de la fenilalanina hidroxilasa, la óxido nítrico sintasa y la gliceril-éter monooxigenasa [6]. Por tanto, la deficiencia de BH4 no sólo causa un descenso de la concentración de NT, sino que, además, es habitualmente responsable del acúmulo de fenilalanina; este último es detectable en el cribado neonatal [7]. Estos casos, cuya incidencia es de sólo uno de cada 200 pacientes con hiperfenilalaninemia (HPA), se deben a deficiencia de BH4 (HPA maligna BH4 además participa en el paso de fenilalanina a tirosin, y de arginina a citrulina+ NO Hay defectos de las pterinas que no causan HPA, como son las deficiencias en los enzimas GTP ciclohidroxilasa I y sepiapterina reductasa (SR). Estas deficiencias afectan únicamente al SNC. Para su diagnóstico se necesita la cuantificación de pterinas y de NT en el LCR Tyrosine hydroxylase (TH) converts tyrosine to L-dopa. This is the rate limiting step in the biosynthesis of the catecholamines. Tryptophan hydroxylase converts tryptophan to 5-hydroxytryptophan (5-HTP) and it is the rate-limiting enzyme in the biosynthesis of serotonin. Both hydroxylases need tetrahydrobiopterin (BH4) as a cofactor (Fig. 1) (Blau et al 2001a; Kandel et al 2000). L-Dopa and 5-HTP undergo decarboxylation through the action of a common enzyme, the pyridoxine- dependent aromatic L-amino-acid decarboxylase (AADC), which leads to the formation of dopamine and serotonin respectively. Within noradrenergic neurons, dopamine is converted to norepinephrine using dopamine b-hydroxylase (DBH) and within the adrenal medulla norepinephrine is methylated to form epinephrine (Fig. 1). Within the pineal gland, serotonin is methylated to melatonin (Kandel et al 2000; Blau et al 2001a; Kandel et al 2000). Following release of dopamine and serotonin, these compounds are rapidly catabolized. This involves the action of monoamine oxidases (MAO) and catechol-O-methyltransferase (COMT), with the formation of homovanillic acid (HVA) from dopamine, 5-hydroxyindoleacetic acid (5-HIAA) from serotonin and 3-methoxy-4-hydroxyphenylglycol (MHPG) from norepinephrine and epinephrine (Fig. 1). The levels of these metabolites in spinal fluid reflect the turnover of the biogenic amines within the brain (Blau et al 2001a; Hyland 2008; Kandel et al 2000). BH4 is the cofactor of tyrosine and tryptophan hydroxylase mentioned above and it is also the cofactor of phenylalanine hydroxylase, which converts phenylalanine to tyrosine in the liver. BH4 is formed in a 3-step pathway from GTP, including GTP cyclohydrolase (GTPCH), 6-pyruvoyltetrahydropterin synthase (PTPS) and sepiapterin reductase (SR). Following oxidation of BH4 in the hydroxylation reactions, there is a recycling back to the active form via the action of pterin 4a-carbinolamine dehydratase (PCD) and dihydropteridine reductase (DHPR) (Fig. 1) (Blau et al 2001a). Kurian MA, et al. The monoamine neurotransmitter disorders: an expanding range of neurological syndromes. Lancet Neurol 2011; 10: 721–33

12 Gliceril-eter monooxigenasaMetabolismo de BH4 Además cofactor de: 3 NO sintasas Gliceril-eter monooxigenasa The tetrahydrobiopterin (BH4) cofactor is essential for various enzyme activities, and is involved in a number of less defined functions on the cellular level (Blau, 2006). The enzymes that depend on BH4 are the phenylalanine, tyrosine, and tryptophan hydroxylases, all three NO synthase (NOS) isoforms, and the glyceryl-ether monooxygenase The de novo biosynthesis pathway of BH4 from GTP involves GTP cyclohydrolase I (GTPCH, gene symbol GCH1; MIM]s and ), 6-pyruvoyl-tetrahydropterin synthase (PTPS, gene symbol PTS; MIM] ), and sepiapterin reductase (SR, gene symbol SPR; MIM] ). Three additional enzymes can replace SR by catalyzing the last two reduction steps: aldose reductase (AR, gene symbol AKR1B1; MIM] ), carbonyl reductase (CR, gene symbol CBR1; MIM] ), and 3ahydroxysteroid dehydrogenase type 2 (HSDH2, gene symbol AKR1C3; MIM] ) [Iino et al., 2003; Park et al., 1991]. Cofactor regeneration requires pterin-4a-carbinolamine dehydratase (PCD, gene symbol PCBD, MIM]s and ) and dihydropteridine reductase (DHPR, gene symbol QDPR; MIM] 261630). PCD was alternatively termed DCoH, for dimerization cofactor of hepatocyte nuclear factor 1a (HNF-1a), as it has been shown to be a protein with dual function [Mendel et al., 1991]. An overview on the BH4-metabolic enzymes, their corresponding genes, and MIM numbers is given in Table 1. BH4 deficiencies, a group of rare inherited neurological diseases with catecholamine and serotonin deficiency, may present phenotypically with or without hyperphenylalaninemia (HPA) [Blau et al., 2001b]. They are a heterogenous group of diseases affecting either all organs, including the central nervous system, only the peripheral hepatic phenylalanine hydroxylating system, or only the nervous system. BH4 deficiency presenting with HPA can be caused by mutations in genes encoding the enzymes involved in its biosynthesis (GTPCH and PTPS) [Tho¨ny and Blau, 1997] or regeneration (PCD/DCoH and DHPR) [Dianzani et al., 1998; Tho¨ny et al., 1998b]. The mutations are all inherited in an autosomal recessive fashion. The autosomal dominant inherited form of GTPCH deficiency (adGTPCH; Dopa-responsive dystonia; DRD), initially described as Segawa disease [Segawa et al., 1976], together with SR deficiency [Bonafe´ et al., 2001] present both without elevated plasma phenylalanine levels in infancy, and thus, in contrast to classical BH4 deficiencies, can not be detected through the newborn screening for phenylketonuria (PKU). HUMAN MUTATION 27(9),870^878,2006 Tetrahydrobiopterin is synthesized in three steps from GTP (Fig ). Deficiencies have been identified in each of the enzymes in this pathway: GTP cyclohydrolase I, 6-pyruvoyltetrahydropterin synthase (GTPCHI), and sepiapterin reductase. Tetrahydrobiopterin is a necessary cofactor for both tryptophan hydroxylase and tyrosine hydroxylase. Therefore, enzymatic deficiencies that lead to reduced levels of tetrahydrobiopterin lead to chronically low levels of the monoamine neurotransmitters. Pearl PL. Monoamine neurotransmitter deficiencies. Handb Clin Neurol. 2013;113: Longo N. Disorders of biopterin metabolism. J Inherit Metab Dis (2009) 32:333–342

13 Metabolismo de BH4 Tetrahydrobiopterin is synthesized in three steps from GTP (Fig ). Deficiencies have been identified in each of the enzymes in this pathway: GTP cyclohydrolase I, 6-pyruvoyltetrahydropterin synthase (GTPCHI), and sepiapterin reductase. Tetrahydrobiopterin is a necessary cofactor for both tryptophan hydroxylase and tyrosine hydroxylase. Therefore, enzymatic deficiencies that lead to reduced levels of tetrahydrobiopterin lead to chronically low levels of the monoamine neurotransmitters. Longo N. Disorders of biopterin metabolism. J Inherit Metab Dis (2009) 32:333–342

14 Defectos del metabolismo de BH4Descritos inicialmente en pacientes con hiperfenilalaninemia (HFA) que desarrollaron deterioro neurológico progresivo pese a óptimo control metabólico: HFA maligna Debido a actividad defectuosa de hidroxilasas de fenilalanina, tirosina y triptofano Existen 5 condiciones genéticas distintas que afectan la síntesis o regeneración de BH4 Sólo una relativamente benigna Todas pesquisables por HFA en screening neonatal, excepto GTPCH AD Déficit de SR Defects in the metabolism or regeneration of tetrahydrobiopterin (BH4) were initially discovered in patients with hyperphenylalaninaemia who had progressive neurological deterioration despite optimal metabolic control (malignant hyperphenylalaninaemia). BH4 is an essential cofactor not only for phenylalanine hydroxylase, but also for tyrosine and two tryptophan hydroxylases, three nitric oxide synthases, and glyceryl-ether monooxygenase. Defective activity of tyrosine and tryptophan hydroxylases explains the neurological deterioration in patients with BH4 deficiency with progressive mental and physical retardation, central hypotonia and periph Alteración BH4 solo en cerebro Longo N. Disorders of biopterin metabolism. J Inherit Metab Dis (2009) 32:333–342

15 Trastorno del metabolismo de las monoaminas: clasificación clínicaExplicar q solo los de BH4 pueden cursar con HFA Kurian MA, et al. The monoamine neurotransmitter disorders: an expanding range of neurological syndromes. Lancet Neurol 2011; 10: 721–33

16 Errores congénitos del metabolismo de las pterinasDéficit de BH4 Errores congénitos del metabolismo de las pterinas Con HFA Déficit de GTPCH AR Déficit de PTPS Déficit de PCD Déficit de DHPR Sin HFA Déficit de GTPCH AD Déficit de SR

17 Clínica: Síntomas y signos sugerentesManifestaciones extrapiramidales Síntomas autonómicos FORMAS DE PRESENTACIÓN DE LOS ECM DE LOS NT EN EDAD PEDIÁTRICA La combinación de algunos signos y síntomas (individualmente inespecíficos), junto con su carácter fluctuante, la ausencia de síntomas extraneurológicos y otras peculiaridades que describiremos a continuación pueden ayudarnos en el proceso diagnóstico. Existe una sintomatología propia de cada uno de los déficit: dopaminérgicos, serotoninérgicos o gabérgicos. Así, los déficit de dopamina suelen producir hipomimia, hipocinesia, hipersalivación, miosis, ptosis, crisis oculogiras, fluctuación a lo largo del día y discinesias. Los déficit de serotonina ocasionan fundamentalmente anomalías en la regulación de la temperatura y del sueño, y los trastornos del metabolismo del GABA, encefalopatías epilépticas. No obstante, no siempre existen unos límites tan bien definidos, y un déficit en concreto puede compartir características propias de otras vías metabólicas. Para el análisis de las características clínicas de los defectos de los NT proponemos dos vías de abordaje: por un lado, identificar aquellos signos y síntomas que nos harían pensar en este tipo de trastornos (Tabla I) y, por otro, conocer las formas de presentación más habituales según la edad del paciente (Tablas II y III). Symptoms are determined by the type and severity of the disorder and are dominated by neurological features, including developmental delay, pyramidal and extrapyramidal motor disorders, epilepsy, autonomic dysfunction, and neuropsychiatric symptoms. Overall, the clinical phenotype mimics that of many other neurological disorders and, therefore, misdiagnosis or diagnostic delay are common. Onset can occur at any age but is most frequently in infancy or early childhood. Proposed signs of dopamine defi ciency include parkinsonism, dystonia, chorea, oculogyric crises, ptosis, hypersalivation, and myoclonic epilepsy. Non-specifi c symptoms include epileptic encephalopathy, progressive cognitive dysfunction, microcephaly, swallowing diffi culties, and pyramidal tract features. The mani festations of serotonin defi ciency are less well defi ned, but include temperature instability, sweating, and possibly dystonia Pearl PL. Monoamine neurotransmitter deficiencies. Handb Clin Neurol. 2013;113: Assmann B, et al. Approach to the Diagnosis of Neurotransmitter Diseases Exemplified by the Differential Diagnosis of Childhood-Onset Dystonia. Ann Neurol 2003;54(S6):S18–24

18 Clínica: Síntomas y signos sugerentesA phenotypic continuum has been proposed for GTPCH deficiency (Horvath et al 2008) that can also be applied for the other disorders of monoamine synthesis. Patients can show a severe phenotype with onset of symptoms in early infancy and minimal developmental progress; an intermediate phenotype with delayed or even normal early developmental progress and with variable onset ranging from infancy, childhood to later in life; and a mild phenotype with onset in infancy (Table 3). Notably, no consistent correlation with the molecular defect or the residual enzyme activity and clinical phenotype has been detected in these disorders (Blau et al 2001a). Pons R. The phenotypic spectrum of paediatric neurotransmitter diseases and infantile parkinsonism. J Inherit Metab Dis (2009) 32:321–332

19 Enfermedades de los NT que se presentan a partir de los 2 añosClasificación Enfermedades de los NT que se presentan entre los 0 y 2 años Enfermedades de los NT que se presentan a partir de los 2 años Clínica marcada con trastornos del movimiento Deficiencia de GTPH autosómica dominante (Segawa- distonía sensible a DOPA) Encefalopatía grave de inicio precoz, progresiva, asociada a alteraciones de las monoaminas Deficiencia de Tirosina Hidroxilasa (TH) Deficiencia de 1- aminoácido decarboxilasa (AADC) Déficit de triptófano hidroxilasa (TPH) ECM de las Pterinas Déficit de Sepiapterina Reductasa (SR) Deficiencia de GTPCH I (AR)

20 Diagnóstico Historia clínica Examen físico Estudio: BioquímicoEnsayo enzimático (para algunos trastornos) Estudio de mutaciones genéticas Kurian MA, et al. The monoamine neurotransmitter disorders: an expanding range of neurological syndromes. Lancet Neurol 2011; 10: 721–33

21 Diagnóstico diferencialDistonías relacionadas con trastornos neurometabólicos Distonías primarias y paroxísticas de la infancia DYT-1 Coreoatetosis kinesogénica paroxística Distonía no kinesogénica Distonía inducida por ejercicio Pearl PL. Monoamine neurotransmitter deficiencies. Handb Clin Neurol. 2013;113:

22 Diagnóstico diferencialPearl PL. Monoamine neurotransmitter deficiencies. Handb Clin Neurol. 2013;113:

23 Screening en RN de HFA Blau N et al. Diagnosis, classification, and genetics of phenylketonuria and tetrahydrobiopterin (BH4) deficiencies.. Mol Genet Metab. 2011;104 Suppl:S2-9

24 Estudio Medición en sangre y orina de pterinas y metabolitos de aminas biógenas Concentración NT en LCR Dado que hay trastornos de la vía de las pterinas que cursan sin hiperfenilalaninemia Fenilalanina hepática intacta Desafíos técnicos Labilidad de BH4 en LCR muestra en N líquido o hielo seco Almacenar -80°C Variabilidad en niveles de NT durante el día Alteraciones secundarias de los metabolitos de monoamina en LCR: convulsiones, hipoxia, infecciones o condiciones neurogenéticas correlacionar con la clínica Concentrations of individual pterin species (eg, tetrahydrobiopterin [BH4], neopterin, and biopterin) and folate should also be measured. Neurotransmitter analysis in CSF must be done by a specialist neurometabolic laboratory that has strict protocols for sample collection and test interpretation.2,31 Samples must be snap frozen in liquid nitrogen or dry ice because BH4 in CSF is labile.32 Individual pterin species require special preservatives in the sample collection tubes. Red blood cells in the CSF lead to rapid oxidation of neurotransmitter metabolites and bloodcontaminated samples must be centrifuged immediately, after which clear CSF should be transferred to new tubes before freezing. CSF samples must be stored at –80°C until analysis. Diurnal variation can affect metabolite levels and, therefore, the time of collection should be recorded. High-pressure liquid chromatography with electrochemical detection and reversed phase column is the most widely used method.28 The rostrocaudal gradient of neurotransmitter metabolites and BH4 requires that the same fractions of CSF are used for all metabolite analyses and that results are compared with established age-matched reference ranges.9 Concentrations of dopamine and serotonin metabolites are high at birth but decrease rapidly within the fi rst few months of life then more slowly into adulthood.11 High concentrations of HVA and 5-HIAA in infants are thought to be required for the regulation of the metabolic pathways during mitosis, neurogenesis, migration, and formation of dopaminergic neuron networks Kurian MA, et al. The monoamine neurotransmitter disorders: an expanding range of neurological syndromes. Lancet Neurol 2011; 10: 721–33

25 Estudio CSF for neurotransmitter analysis is obtained by lumbarpuncture. Concentrations of the amine neuro transmitter metabolites homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA), which are the stable degradation products of dopamine and serotonin, respectively, refl ect turnover of these biogenic amines in the mesolimbic and mesostriatal areas of the brain.28–30 Concentrations of individual pterin species (eg, tetrahydrobiopterin [BH4], neopterin, and biopterin) and folate should also be measured. Neurotransmitter analysis in CSF must be done by a specialist neurometabolic laboratory that has strict protocols for sample collection and test interpretation.2,31 Samples must be snap frozen in liquid nitrogen or dry ice because BH4 in CSF is labile.32 Individual pterin species require special preservatives in the sample collection tubes. Red blood cells in the CSF lead to rapid oxidation of neurotransmitter metabolites and bloodcontaminated samples must be centrifuged immediately, after which clear CSF should be transferred to new tubes before freezing. CSF samples must be stored at –80°C until analysis. Diurnal variation can aff ect metabolite levels and, therefore, the time of collection should be recorded. High-pressure liquid chromatography with electrochemical detection and reversed phase column is the most widely used method.28 The rostrocaudal gradient of neurotransmitter metabolites and BH4 requires that the same fractions of CSF are used for all metabolite analyses and that results are compared with established age-matched reference ranges.9 Concentrations of dopamine and serotonin metabolites are high at birth but decrease rapidly within the fi rst few months of life then more slowly into adulthood.11 High concentrations of HVA and 5-HIAA in infants are thought to be required for the regulation of the metabolic pathways during mitosis, neurogenesis, migration, and formation of dopaminergic neuron networks Pearl PL. Monoamine neurotransmitter deficiencies. Handb Clin Neurol. 2013;113:

26 Estudio Actividad enzimática Test de carga de fenilalaninaCarga oral PHE ↑ PHE/tirosina Déficit en metabolismo BH4 PHE/tirosina normal Actividad enzimática No de rutina, se prefiere estudio genético Puede ser útil para evaluar actividad GTPCH en fibroblastos en pacientes con sospecha de forma AD, particularmente si el perfil de NT en LCR es atípico y el screening GCH1(-) Test de carga de fenilalanina Útil en trastornos del metabolismo pterinas SIN HFA Carga oral de PHE Falsos positivos y negativos, interpretar con precaución In disorders of biopterin metabolism without hyperphenylalaninaemia an oral phenylalanine load test can be useful. A raised ratio of phenylalanine to tyrosine in serum after oral phenylalanine loading suggests a defect in BH4 metabolism. Measurements are usually taken at 1, 2, 4, and 6 h, but one measurement 2–4 h after ingestion could be sufficient for diagnosis, especially if accompanied by a decline in biopterin concentration. Normalisation of serum tyrosine concentration after phenylalanine load combined with BH4 supplementation indicates a BH4 defect. The potential for false-negative results in patients with true GTPCH deficiency and false-positive results in carriers of PAH mutations associated with phenylketonuria means that results must be interpreted with caution, in the context of results from clinical, biochemical, and molecular genetic investigations, and in comparison with appropriate agematched reference values Si normaliza con carga PHE+ BH4 > orientador Kurian MA, et al. The monoamine neurotransmitter disorders: an expanding range of neurological syndromes. Lancet Neurol 2011; 10: 721–33

27 Diagnóstico Kurian MA, et al. The monoamine neurotransmitter disorders: an expanding range of neurological syndromes. Lancet Neurol 2011; 10: 721–33

28 Diagnóstico Diagnostic algorithm for patients with a possible disorder of neurotransmitter metabolism. Sepiapterin reductase (SR) deficiency and other disorders of neurotransmitter metabolism should be considered in patients with: (1) developmental delay with hypotonia, (2) suspect but unexplained cerebral palsy (CP) or CP with atypical features, and (3) uncharacterized L-dopa–responsive motor disorders. (1) In a patient with developmental delay and hypotonia, if oculogyric crises, diurnal fluctuation, sleep disturbance, or extrapyramidal or autonomic signs exist, a disorder of neurotransmitter biosynthesis is likely and cerebrospinal fluid (CSF) analysis should be done. If no other signs are present, CSF analysis should be considered if standard workup for hypotonia is unrevealing. If CSF analysis is abnormal, then mutational screening and/or measurement of enzymatic activity can be targeted to confirm the specific disorder suggested by the pattern of CSF abnormalities. If CSF evaluation is impractical, alternative evaluation may include L-dopa trial and/or phenylalanine load. If negative, CSF analysis must still be done to exclude a disorder of neurotransmitter metabolism. If L-dopa trial and/or phenylalanine loading are positive, CSF analysis will allow targeted mutational screening; however, one should keep in mind that phenylalanine (Phe) load can be positive in heterozygote carriers for phenylketonuria. Alternatively, CSF analysis may be skipped and broad mutational screening undertaken. Mutational and gene dosage screening may be time-consuming and costly, and false negatives may still occur. Therefore, this alternative evaluation route should be reserved for cases in which CSF analysis is not available or is declined, or in which other clinical features lead to suspicion of a specific diagnosis. (2) In a patient with unexplained CP or CP with atypical features, a disorder of neurotransmitter metabolism should be considered and diagnostic algorithm, as outlined above, should be followed. Atypical or unexplained features suggesting need for further metabolic investigation in a child with possible CP include lack of adequate antecedent, nondiagnostic magnetic resonance imaging, progressive symptoms, familial occurrence, episodic encephalopathy, and features not expected in the CPs such as diurnal variation, sleep disturbance, autonomic symptoms, or oculogyric crises.22 (3) All patients with an L-dopa–responsive motor disorder should be evaluated for a disorder of neurotransmitter metabolism. CSF analysis (after discontinuation of L-dopa therapy for at least 10 days) is the recommended first step. If L-dopa withdrawal is impractical, the results of CSF analyses may still be informative if either pterins or 5-hydroxyindoleacetic acid levels are abnormal. Alternatively, molecular investigations can be done, guided either by results of phenylalanine loading test or clinical symptoms with caveats as noted above.1 CSF analysis should consist of homovanillic acid, 5- hydroxyindoleacetic acid (5HIAA), pterins (neopterin, biopterin, and sepiapterin), and 5-methyltetrahydrofolate. Friedman et al. Sepiapterin Reductase Deficiency: A Treatable Mimic of Cerebral Palsy. Ann Neurol 2012;71:520–530

29 Defecto del metabolismo de las pterinas sin HFA

30 Déficit de GTPCH AD o Enfermedad de SegawaDefecto del metabolismo de las pterinas sin HFA A.1 También llamada distonía respondedora a dopa, DYT5a o Distonía hereditaria progresiva con marcada fluctuación diurna Descrita por Segawa et al. en 1971: enfermedad hereditaria de los ganglios basales con marcada fluctuación diurna Mutación en el gen de GTP ciclohidrolasa 1 Clínicamente existen 2 tipos: Depende de la familia o el loci de la mutación Distonía postural Síntomas similares inter e intrafamiliar Distonía de acción Síntomas con variaciones intrafamiliares The responsible gene has been mapped to chromosome region 14q22.1- q22.2 spanning a 30 kb region and containing six exons. A disparate collection of mutations with variable penetrance has been reported Kurian MA, et al. The monoamine neurotransmitter disorders: an expanding range of neurological syndromes. Lancet Neurol 2011; 10: 721–33 Segawa M. Hereditary progressive dystonia with marked diurnal fluctuation. Brain & Development 33 (2011) 195–201 Pearl PL. Monoamine neurotransmitter deficiencies. Handb Clin Neurol. 2013;113:

31 Déficit de GTPCH AD o Enfermedad de Segawa: FisiopatologíaDefecto del metabolismo de las pterinas sin HFA Déficit de GTPCH AD o Enfermedad de Segawa: Fisiopatología A.1 Mutación en el gen de GTP ciclohidrolasa 1 (GCH-1) Ubicado en cromosoma14q22.1-q22.2 Deficiencia parcial de la actividad de la enzima >100 mutaciones en región codifcante independientes descritas La misma intrafamiliar, distintas interfamiliar Aprox 40% no se determina la mutación Herencia AD, mayor penetrancia en mujeres (87%) que en hombres (38%) Agregar referencias de reporte de casos con mutaciones raras Alteraciones en deleción de intrones genómicos, deleción grande del gen, duplicación o inversión intragénica Mutación de un gen regulador que modifique función enzmática aún no determinada Segawa M. Hereditary progressive dystonia with marked diurnal fluctuation. Brain & Development 33 (2011) 195–201

32 Déficit de GTPCH AD o Enfermedad de Segawa: FisiopatologíaDefecto del metabolismo de las pterinas sin HFA Déficit de GTPCH AD o Enfermedad de Segawa: Fisiopatología A.1 Defecto afecta la síntesis de BH4 Debiera afectar triptofano hidroxilasa (TPH) tanto como la TH (vía serotonina igual de afectada que la de dopamina) Mutación heterocigota déficit parcial de BH4 TH > TPH afinidad por BH4 En condiciones en que BH4 está marcadamente disminuida afectación de TH=TPH síntomas de vía serotonina . There is the difference of Km value for TH and TPH. With heterozygous mutant gene, the BH4 decreases partially in HPD. Thus TH with higher affinity to BH4 is affected rather selectively [3,4]. However, in molecular conditions with marked decrease of BH4, TPH is affected as well as TH and may produce symptoms induced by deficiencies of the 5HT neurons Pteridine metabolism develops in late fetal period with critical period in early infancy which extends to early childhood [19]. Study in stimulated mononuclear blood cells [20] also showed age-dependent decrement of the activities of GCH-1 in the first three decades of life. Thus pteridine metabolism may involve in the age related decrement of TH activity [10] particularly in its early phase. TH se afecta selectivamente por su mayor afinidad a BH4 Segawa M. Hereditary progressive dystonia with marked diurnal fluctuation. Brain & Development 33 (2011) 195–201 Pearl PL. Monoamine neurotransmitter deficiencies. Handb Clin Neurol. 2013;113:

33 Déficit de GTPCH AD o Enfermedad de Segawa: FisiopatologíaDefecto del metabolismo de las pterinas sin HFA A.1 Postural tremor, torticollis and generalized rigid hypertonus develop later independently from postural dystonia. The side predominance of these symptoms is ipsilateral both in the extremities and in the SCM. This implicates a causative lesion located in the downstream of the striatum. As these symptoms are DA responsive, it is suggested that hypofunction of the DA neuron projecting to the D1 receptor on the subthalamic nucleus (STN) is postulated to be involved Furthermore, results of the stereotactic surgeries and the paired pulse transcranial magnetic stimulation show involvement of the ascending output of the basal ganglia in tremor, focal and segmental dystonia and rigidity in adult onset cases. These processes are also involved in focal dystonia. Whereas, dopa-responsive growth arrest seen in children with HPD postulates the involvement of D4 receptor of the tuberoinfundibular tract. The D4 receptor belongs to the D2 receptor family, which matures early among D2 families [3,4]. This implicates that the terminals of the NS-DA neuron in HPD connect to the receptors which develop early Segawa M. Hereditary progressive dystonia with marked diurnal fluctuation. Brain & Development 33 (2011) 195–201

34 Déficit de GTPCH AD o Enfermedad de Segawa: ClínicaDefecto del metabolismo de las pterinas sin HFA A.1 Distonía fluctuante Temblor CI normal Espectacular respuesta a L-DOPA En la mayoría de los casos el síntoma inicial es postura distónica de una extremidad inferior, pie equinovaro, alrededor de los 6 años Progresa a todos los miembros y tronco (adolescencia) Rigidez se agrava progresivamente hasta los 20 años La progresión se relentece en la 2° década Se hace estacionaria en los 30 Luego de 10 años aparece temblor postural 8-10 Hz en EESS, se expande a todos los miembros a los 30 La locomoción se preserva The response to L-DOPA in this syndrome may be overwhelming and profoundly life altering at any age. While this is not the only form of dystonia that mayrespond to dopamine, it has the most prominent and rewarding response Typically, postural dystonia or tremor, often starting in one extremity, may appear between 6 and 10 years of age and spread to all limbs over the next decade or longer. The progression of dystonia appears to become static in the fourth decade of life, while postural tremor may continue to progress. Isolated toe gait, a female predominance, and presentation with only prominent postural tremor in adulthood have all been described Kurian MA, et al. The monoamine neurotransmitter disorders: an expanding range of neurological syndromes. Lancet Neurol 2011; 10: 721–33 Segawa M. Hereditary progressive dystonia with marked diurnal fluctuation. Brain & Development 33 (2011) 195–201 Pearl PL. Monoamine neurotransmitter deficiencies. Handb Clin Neurol. 2013;113:

35 Déficit de GTPCH AD o Enfermedad de Segawa: ClínicaDefecto del metabolismo de las pterinas sin HFA A.1 Correlation of the 43 years clinical course of 51 years female postural type, with onset at 8 years and the age variation of the tyrosine hydroxylase activities of the terminals of the nigrostriatal dopamine neuron as the causative nucleus shown by McGeer and McGeer [9]. This case was completely recovered by L-dopa started at 51 years which continued without any side effects until 90 years. Segawa M. Hereditary progressive dystonia with marked diurnal fluctuation. Brain & Development 33 (2011) 195–201

36 Déficit de GTPCH AD o Enfermedad de Segawa: ClínicaDefecto del metabolismo de las pterinas sin HFA A.1 En el tipo Distonía de acción, además aparecen movimientos de una extremidad superior o retrocollis de acción alrededor de los 8 años Puede asociarse a crisis oculógiras Tortícolis y calambre del escribidor aparecen en la adultez En la familia hay casos de inicio en la adultez con calambre del escribidor, tortícolis o rigidez generalizada con temblor postural, sin posturas distónicas ni progresión aparente Predominancia masculina Inicio en la niñez: Inicio precoz: RDSM A few patients show migraineous headache, autistic features, depressive reaction or obsessive behavior. Patients with onset early in infancy start with delay in motor and psychomental development. Childhood onset cases show marked female predominance. In our personal cases (41 cases from 20 families) F:M is 33:8, that is 4:1, and it is more marked in postural type 18:1 than action type 2:1. While adult onset cases show male predominance. Furukawa et al. [5] showed higher penetrance (87%) in females than males (38%). Marcada fluctuación diurna, luego se atenúa en la adultez Estancamiento del crecimiento longitudinal con el inicio de la distonía Marcada predominancia femenina (4:1) Postural 18:1 Acción 2:1 Segawa M. Hereditary progressive dystonia with marked diurnal fluctuation. Brain & Development 33 (2011) 195–201

37 Déficit de GTPCH AD o Enfermedad de Segawa: Examen físicoDefecto del metabolismo de las pterinas sin HFA A.1 Rigidez no plástica Casos con temblor sin rueda dentada Asimetría rigidez y temblor En niñez ROT ↑, clonus (+), con plantares flexores Enfermedad avanzada: pulsión, sin freezing Cerebelo y sensibilidad sin alteraciones Inicio precoz: hipotonía tronco, RDSM motor, camptocormia en la niñez tardía, parkisonismo en la adultez Talla baja se recupera si se inicia tratamiento antes de la adolescencia flexión permanente del tronco durante la bipedestación y la marcha, con corrección total con el decúbito dorsal. camptocormia (del griego campto = inclinado , kormos = dorso) para describir un trastorno conversivo postural caracterizado por la flexión permanente del tronco durante la bipedestación que desaparecía por completo con el decúbito dorsal.  se han descrito casos de innegable naturaleza orgánica, en particular se ha vinculado a la enfermedad de Parkinson (5) y a ciertas miopatías axiales Segawa M. Hereditary progressive dystonia with marked diurnal fluctuation. Brain & Development 33 (2011) 195–201

38 Déficit de GTPCH AD o Enfermedad de Segawa: EstudioDefecto del metabolismo de las pterinas sin HFA A.1 RM cerebro: normal Fenilalanina sérica normal Adecuada conversión intrahepática de fenilalanina a tirosina Medición en LCR de NT Niveles bajos de ácido homovanílico, neopterina, 3-O- metildopa (y BH4) Análisis genético Rendimiento 50% (aún no se conoce todas las mutaciones) Considerar presentaciones atípicas: similar a diplejia espástica, distonía de ee asimétrica, calambre del escribiente Segawa M. Hereditary progressive dystonia with marked diurnal fluctuation. Brain & Development 33 (2011) 195–201 Pearl PL. Monoamine neurotransmitter deficiencies. Handb Clin Neurol. 2013;113:

39 Déficit de GTPCH AD o Enfermedad de Segawa: TratamientoDefecto del metabolismo de las pterinas sin HFA A.1 L-Dopa en dosis bajas muestra marcado beneficio Asilada 20 mg/kg/d o 4-5 mg/kg/d asociada a inhibidor de decarboxilasa 20% pacientes presentan diskinesias: Movimientos coreicos con ascenso rápido de dosis o inicio con dosis alta Responde con la disminución de dosis o titulación adecuada Anticolinérgicos: efecto marcado sobre distonía, no en temblor BH4: asociado con L-dopa se ha reportado efecto moderado, sin efecto en monoterapia (Se usa muy raramente) Efectividad mantenida en algunas familias Necesario en algunas familias años después del inicio del tto Respuesta incompleta en distonía de acción y trastornos asociados Retrocolis de acción y crisis oculógiras pueden empeorar inicialmente Más riesgo de diskinesia inducida por L-dopa Patients often benefit significantly with low dose L-DOPA/carbidopa. Efficacy generally persists over time. Dyskinesias, reported in 20% of patients with dopa-responsive dystonia, respond to a reduction in dose (Hwang et al., 2001). Tetrahydrobiopterin may be helpful but is rarely used. The dopamine synthesis line appears far more involved than the serotonergic line; hence, serotonin reuptake inhibitors are not standard therapy In child onset cases, a dose of 20 mg/kg/day of plain levodopa (levodopa without decarboxylase inhibitor) or 4–5 mg/kg/day with decarboxylase inhibitor show complete and sustained effects without side effects [3,4,6]. There are families in which plain levodopa is effective throughout the course. However, in other family, replacement to L-dopa with decarboxylase inhibitor is necessary from around 13 years, because of activation of the decarboxylation of dopa in the intestine [6]. In a few cases choreic movements develop by a rapid increase of dosage or by administration of a high dose of levodopa in initial stage of treatment [4]. In these patients by reduction of the dosage and slow titration to the optimal doses, favorable and sustained effect is obtained without unfavorable side-effects [6]. However, for action dystonia and related symptoms effects of levodopa may be incomplete, and action retrocollis and oculogyric crises may be aggravated by initial doses [3,4]. Furthermore, patients with this type may show levodopa induced dyskinesia. The short stature caused by stagnation of the body length recovers completely, if levodopa is administered before adolescent. Anticholinergics showed a marked and sustained effect for dystonia, but not for tremor [3]. Moderate effects of tetrahydrobiopterin (BH4) with levodopa were reported, but no favorable effects with monotherapy [3]. Segawa M. Hereditary progressive dystonia with marked diurnal fluctuation. Brain & Development 33 (2011) 195–201 Pearl PL. Monoamine neurotransmitter deficiencies. Handb Clin Neurol. 2013;113: |

40 Déficit de Sepiapterina Reductasa (SR)Defecto del metabolismo de las pterinas sin HFA A.2 Trastorno de NT sensible a dopa Muy infrecuente Causado por mutación del gen SPR (2p14-p12) Hasta el momento 14 mutaciones diagnosticadas Herencia AR Thus, autosomal recessive SR deficiency accounts for a small fraction of dopa-responsive dystonia cases which are prevalently caused by a dominant GTP cyclohydrolase I Defect To date, 31 patients with SR deficiency are included in the database of BH4 deficiencies BIODEF (http://www. biopku.org) and a total of 12 different mutations are reported in the SPR gene, mostly of the missense or nonsense type. Most patients present with clinical symptoms before the first year of age corresponding to a dopa-responsive dystonia phenotype with diurnal fluctuations, although some patients exhibit more complex motor and neurologicl phenotypes. Sepiapterin reductase deficiency, the latest of the known inborn errors of pterin deficiencies, was only fully recognized in 2001 Sepiapterin reductase catalyzes the final step in tetrahydrobiopterin synthesis. As with Segawa disease, it too requires analysis of CSF for diagnosis. The clinical phenotype of recessive sepiapterin reductase deficiency includes progressive psychomotor retardation with onset in the first year of life. There are pyramidal (e.g., spasticity) and extrapyramidal signs (dystonia, choreoathetosis, oculogyric crises, tremor). Temperature instability, hypersalivation, hypersomnolence, oculomotor apraxia, and microcephaly have been described in addition to diurnal variation (Bonafe et al., 2001).Amurine model of sepiapterin reductase deficiency confirms that in the absence of this enzyme, there are greatly reduced levels of the catecholamines and serotonin, the neurotransmitters that depend on tetrahydrobiopterin for their synthesis Dill P, et al. Child neurology: paroxysmal stiffening, upward gaze, and hypotonia: hallmarks of sepiapterin reductase deficiency. Neurology Jan 31;78(5):e29-32 Arrabal L, et al. Genotype–phenotype correlations in sepiapterin reductase deficiency. A splicing defect accounts for a new phenotypic variant. Neurogenetics 2011,12:183–91 Friedman et al. Sepiapterin Reductase Deficiency: A Treatable Mimic of Cerebral Palsy. Ann Neurol 2012;71:520–530

41 Déficit de Sepiapterina Reductasa (SR)Defecto del metabolismo de las pterinas sin HFA Déficit de Sepiapterina Reductasa (SR) A.2 Clínica: inicio de síntomas <1 año Trastorno motor respondedora a dopa con fluctuaciones diurnas, en la mayoría de los casos asociados con DI y disfunción neurológica severa Tríada Crisis oculógiras Hipertonía paroxística Hipotonía Diagnóstico: análisis de LCR metabolitos de aminos biógenas y especies pterinas Retraso en el diagnóstico promedio 9,1 años PONER VIDEITO!!!! Thus, autosomal recessive SR deficiency accounts for a small fraction of dopa-responsive dystonia cases which are prevalently caused by a dominant GTP cyclohydrolase I Defect To date, 31 patients with SR deficiency are included in the database of BH4 deficiencies BIODEF (http://www. biopku.org) and a total of 12 different mutations are reported in the SPR gene, mostly of the missense or nonsense type. Most patients present with clinical symptoms before the first year of age corresponding to a dopa-responsive dystonia phenotype with diurnal fluctuations, although some patients exhibit more complex motor and neurological phenotypes. Sepiapterin reductase deficiency, the latest of the known inborn errors of pterin deficiencies, was only fully recognized in 2001 Sepiapterin reductase catalyzes the final step in tetrahydrobiopterin synthesis. As with Segawa disease, it too requires analysis of CSF for diagnosis. The clinical phenotype of recessive sepiapterin reductase deficiency includes progressive psychomotor retardation with onset in the first year of life. There are pyramidal (e.g., spasticity) and extrapyramidal signs (dystonia, choreoathetosis, oculogyric crises, tremor). Temperature instability, hypersalivation, hypersomnolence, oculomotor apraxia, and microcephaly have been described in addition to diurnal variation (Bonafe et al., 2001).Amurine model of sepiapterin reductase deficiency confirms that in the absence of this enzyme, there are greatly reduced levels of the catecholamines and serotonin, the neurotransmitters that depend on tetrahydrobiopterin for their synthesis Dill P, et al. Child neurology: paroxysmal stiffening, upward gaze, and hypotonia: hallmarks of sepiapterin reductase deficiency. Neurology Jan 31;78(5):e29-32 Arrabal L, et al. Genotype–phenotype correlations in sepiapterin reductase deficiency. A splicing defect accounts for a new phenotypic variant. Neurogenetics 2011,12:183–91 Friedman et al. Sepiapterin Reductase Deficiency: A Treatable Mimic of Cerebral Palsy. Ann Neurol 2012;71:520–530 Leuzzi V, et al. Very early pattern of movement disorders in sepiapterin reductase deficiency. Neurology 2013 Dec 10;81(24):2141-2

42 Déficit de Sepiapterina Reductasa (SR): clínicaDefecto del metabolismo de las pterinas sin HFA Déficit de Sepiapterina Reductasa (SR): clínica A.2 PONER VIDEITO!!!! Thus, autosomal recessive SR deficiency accounts for a small fraction of dopa-responsive dystonia cases which are prevalently caused by a dominant GTP cyclohydrolase I Defect To date, 31 patients with SR deficiency are included in the database of BH4 deficiencies BIODEF (http://www. biopku.org) and a total of 12 different mutations are reported in the SPR gene, mostly of the missense or nonsense type. Most patients present with clinical symptoms before the first year of age corresponding to a dopa-responsive dystonia phenotype with diurnal fluctuations, although some patients exhibit more complex motor and neurological phenotypes. Sepiapterin reductase deficiency, the latest of the known inborn errors of pterin deficiencies, was only fully recognized in 2001 Sepiapterin reductase catalyzes the final step in tetrahydrobiopterin synthesis. As with Segawa disease, it too requires analysis of CSF for diagnosis. The clinical phenotype of recessive sepiapterin reductase deficiency includes progressive psychomotor retardation with onset in the first year of life. There are pyramidal (e.g., spasticity) and extrapyramidal signs (dystonia, choreoathetosis, oculogyric crises, tremor). Temperature instability, hypersalivation, hypersomnolence, oculomotor apraxia, and microcephaly have been described in addition to diurnal variation (Bonafe et al., 2001).Amurine model of sepiapterin reductase deficiency confirms that in the absence of this enzyme, there are greatly reduced levels of the catecholamines and serotonin, the neurotransmitters that depend on tetrahydrobiopterin for their synthesis Dill P, et al. Child neurology: paroxysmal stiffening, upward gaze, and hypotonia: hallmarks of sepiapterin reductase deficiency. Neurology Jan 31;78(5):e29-32

43 A.2 Déficit de SR: ClínicaDefecto del metabolismo de las pterinas sin HFA Déficit de SR: Clínica A.2 >65% Relacionados con alteración vía de dopamina y serotonina Manifestaciones cardinales: distonía y fluctuación diurna no son universales (79%) A menudo ausentes precozmente 45-65% We evaluated 43 SR-deficient patients, identified features common to patients with SRD, defined effective treatment strategies, and proposed a diagnostic algorithm for this potentially devastating yet treatable disorder. Forty-three cases with SRD from medical centers in North and South America, Europe, and Asia were identified from 3 Sources Features of SRD, present in >65%, include motor and speech delay, axial hypotonia, dystonia, weakness, and oculogyric crises with diurnal fluctuation and sleep benefit. Frequent clinical features, present in 45 to 65%, include: dysarthria, parkinsonian features (bradykinesia, rigidity, tremor, or masked facies), hyper-reflexia, psychiatric and/or behavioral abnormalities, sleep disturbance, mental retardation, autonomic signs, and limb hypertonia. Numerous other symptoms were reported (Fig 2). Cardinal features of DRD, dystonia and diurnal fluctuation (79%; 30 of 38), were not universal in SRD and were often absent early. Only 40% (12 of 30) of those developing dystonia and 60% (18 of 30) of those with diurnal fluctuations had these symptoms in infancy, the latter recognized sometimes only in retrospect. Even among patients up to 4 years of age at diagnosis (n ¼ 12), dystonia was not a reliable sign, being present in only 50% (6 of 12). In these patients, diurnal fluctuation and oculogyric crises (75%; 9 of 12) were more consistent findings, the latter sometimes mistaken for seizures, especially when associated with more generalized paroxysmal dystonic episodes. The early clinical phenotype is dominated by nonspecific signs: axial hypotonia and developmental delays present in 92% (11 of 12) of patients diagnosed prior to 4 years of age. Distonía sólo 50% pctes con dx >4 años Friedman et al. Sepiapterin Reductase Deficiency: A Treatable Mimic of Cerebral Palsy. Ann Neurol 2012;71:520–530

44 A.2 Déficit de SR: ClínicaDefecto del metabolismo de las pterinas sin HFA Déficit de SR: Clínica A.2 Relacionados con alteración vía de dopamina y serotonina Síntomas particulares son edad específicos Buscar cuantos pctes son!!!! Microcefalia Síntomas pueden interrumpirse por movimientos voluntarios DSM normal: mutaciones que conservan función parcial Dill P, et al. Child neurology: paroxysmal stiffening, upward gaze, and hypotonia: hallmarks of sepiapterin reductase deficiency. Neurology Jan 31;78(5):e29-32 Arrabal L, et al. Genotype–phenotype correlations in sepiapterin reductase deficiency. A splicing defect accounts for a new phenotypic variant. Neurogenetics 2011,12:183–91

45 Déficit de SR: DiagnósticoDefecto del metabolismo de las pterinas sin HFA Déficit de SR: Diagnóstico A.2 Fenilalanina sérica normal, pterinas normales en orina Estudio de LCR ↑ pterinas (↑ ↑sepiapterina) ↓ ácido 5 hidroxindolacetico y ácido homovanílico Actividad sepiapterina reductasa en fibroblastos: confirma Análisis mutación The normal level of biopterin is explained by the existence of a “salvage pathway” of biopterin synthesis [3] leading to reduction of the intermediate 6-pyruvoyl tetrahydropterin to dihydrobiopterin by additional reductases (carbonyl and aldose reductases). These enzymes are primarily active in the liver [2,3], which may explain the almost normal pterin availability in the liver. This fact also explains why cerebrospinal fluid dihydrobiopterin is elevated; but the levels of tetrahydrobiopterin remain at the low normal level because dihydrobiopterin is not efficiently converted to tetrahydrobiopterin owing to the low activity of dihydrofolate reductase in the brain. FIGURE 3: Cerebrospinal fluid (CSF) concentrations (median and 25th–75th percentile) of key neurotransmitter metabolites in patients with sepiapterin reductase deficiency at the time of diagnosis (age, 0.7–27 years; median, 8.3 years). Reference ranges are marked as shaded area. Sepiapterin is not detectable in healthy controls. Reference ranges may differ between laboratories. 5HIAA 5 5-hydroxyindoleacetic acid; BH2 5 7,8-dihydrobiopterin; Bio 5 biopterin; HVA 5 homovanillic acid; Neo 5 neopterin; Sep 5 sepiapterin Dill P, et al. Child neurology: paroxysmal stiffening, upward gaze, and hypotonia: hallmarks of sepiapterin reductase deficiency. Neurology Jan 31;78(5):e29-32 Friedman et al. Sepiapterin Reductase Deficiency: A Treatable Mimic of Cerebral Palsy. Ann Neurol 2012;71:520–530

46 Déficit de SR: TratamientoDefecto del metabolismo de las pterinas sin HFA Déficit de SR: Tratamiento A.2 Sustitución de los precursores L-dopa y 5-hidroxitriptifano L-dopa/carbidopa o benserazida (5 mg/kg/d) + 5-hidroxitriptofano (2,5 mg/kg/día) L-dopa/carbidopa (2 mg/kg/día) Frecuencia 2-5 veces al día Raro: + selegilina o sertralina Therapy. The therapy strategy is straightforward by substituting both precursor substances L-dopa and 5-hydroxytryptophan, enabling a normalization of the CSF profile. Data were available in 20 cases, including our case. In 9/20 cases, a combination therapy with L-dopa/ carbidopa or benserazide (median 5 mg/kg/day, range 1.45–20 mg/kg/day) and 5-hydroxytryptophan (median 2.5, range 0.75–16 mg/kg/day) was administered. Eleven of 20 patients were treated with L-dopa/carbidopa (median 2 mg/kg/day, range 0.65–5.9 mg/kg/day) alone. The frequency of application was 2–5 times daily. Rarely, other substances were administered, such as selegiline and sertraline.2,4 Hypersomnia was treated well with melatonin in one case.4 Clinically the therapy provides a significant and rapid improvement (within hours) of the motor deficits, in some cases enabling immediate sitting, walking, and talking in patients who were not able to stand independently and speak more than a single word before treatment.3,7,8 Fourteen of 20 cases showed partial improvement of motor symptoms, whereas 6/20 cases could achieve a normalization of motor skills. Unfortunately, there are dosagedependent side effects such as facial and limb dyskinesias which were observed in 5/20 cases and chorea in one case, especially when the dosage of L-dopa was elevated too fast.7,9 In one case, L-dopa had to be discontinued due to transaminase elevations. Severe vomiting occurred in 2/8 cases with 5-hydroxytryptophan. The combination therapy is assumed to be the optimal therapeutic strategy, but it has to be noted, especially since 5-hydroxytryptophan is not available everywhere. Most patients seem to respond to a combination therapy with L-dopa and 5-hydroxytryptophan. Since some patients might easily get side effects, we recommend a very low starting dosage of about 0.5 to 2 mg/kg/day. Because of the short half-life period of L-dopa, the ideal application rate would be at least 3 times daily. For follow-up the analysis of prolactin levels in serum has shown to be a useful surrogate parameter for dopamine metabolism, if it was elevated prior to therapy Mejoría clínica rápida (en horas) del déficit motor Parcial o total Sin efecto sobre el rendimiento cognitivo DI leve asevera CI normal 3/21 pacientes Vómitos severos en algunos pacientes con 5-hidroxitriptofano Dill P, et al. Child neurology: paroxysmal stiffening, upward gaze, and hypotonia: hallmarks of sepiapterin reductase deficiency. Neurology Jan 31;78(5):e29-32 Friedman et al. Sepiapterin Reductase Deficiency: A Treatable Mimic of Cerebral Palsy. Ann Neurol 2012;71:520–530

47 Defecto del metabolismo de las pterinas con HFA

48 Defecto del metabolismo de las pterinas con HFAThe present study summarizes the clinical and biochemical data, the treatment, and the follow-up data of 626 patients with different forms of BH4 deficiency who were included in the International Database of BH4 Deficiencies (BIODEF; Up to 57 % of neonates with BH4 deficiencies are already clinically symptomatic. During infancy and childhood, the predominant symptoms are muscular hypotonia, mental retardation and age-dependent movement disorders, including dystonia. The laboratory diagnosis of BH4 deficiency is based on a positive newborn screening (NBS) for phenylketonuria (PKU), characteristic profiles of urinary or dried blood spot pterins (biopterin, neopterin, and primapterin), and the measurement of DHPR activity in blood. Some patients with autosomal recessive GTPCH deficiency and all with sepiapterin reductase deficiency may be diagnosed late due to normal blood phenylalanine in NBS. L-dopa, 5-hydroxytryptophan, and BH4 are supplemented in PTPS and GTPCH-deficient patients, whereas L-dopa, 5-hydroxytryptophan, folinic acid and diet are used in DHPR-deficient patients. Medication doses vary widely among patients, and our understanding of the effects of dopamine agonists and monoamine catabolism inhibitors are limited. Conclusions BH4 deficiencies are a group of treatable pediatric neurotransmitter disorders that are characterized by motor dysfunction, mental retardation, impaired muscle tone, movement disorders and epileptic seizures. Although the outcomes of BH4 deficiencies are highly variable, early diagnosis and treatment result in improved outcomes. According to the International Database of Tetrahydrobiopterin Deficiencies database, which includes patients of various races, PTPS deficiency (MIM #261640) represents the most common cause (approximately 60%) of BH4 deficiencies, while deficiency of DHPR, GTPCH, and PCD represent 32%, 4%, and 5% of all cases of BH4 deficiencies, respectively

49 Déficit de GTPCH autosómica recesivaDefecto del metabolismo de las pterinas con HFA Déficit de GTPCH autosómica recesiva B.1 Mutación rara de GTPCH (solo 5 de 104 alelos mutantes) <10% casos déficit GTPCH 1 Causa reducción severa de BH4 hiperfenilalaninemia (HFA) Distonía respondedora a dopa de herencia AR generalmente por déficit de otras enzimas, sin HFA Fenotipo más complejo, respuesta moderada a L-dopa (síndromes DRD plus) Manifestación cardinal HFA Casos reportados de Sd. DRD-plus de GCH1 AR sin HFA Clínica Inicio en la infancia, generalmente con RDSM, piramidalismo, distonía, temblor, convulsiones y disfunción autonómica Diagnóstico diferencial: otros trastornos de NT, trastornos metabólicos, PC only 5 out of 104 mutant alleles, present in a homozygous state, are reported to cause the autosomal recessive form of inheritable hyperphenylalaninemia (HPA) associated with monoamine neurotransmitter deficiency Autosomal recessive GTPCH deficiency Onset of autosomal recessive GTPCH deficiency (OMIM #233910) is during infancy, and generally presents with developmental delay, pyramidal tract features, dystonia, athetosis, tremor, seizures, and autonomic dysfunction. This disorder clinically mimics several neurological disorders, including other neurotransmitter defects alternating hemiplegia of childhood, metabolic disorders, and cerebral palsy. Most patients are identified by the presence of hyperphenylalaninaemia in neonatal blood spot screening. Biopterin and neopterin concentrations in urine are low, as are concentrations of HVA, 5-HIAA, and pterins in CSF. Measurement of enzyme activity can be helpful to confirm the diagnosis. Patients have homozygous or compound heterozygous mutations in GCH1 (OMIM *600225). Autosomal recessive GTPCH deficiency accounts for less than 10% of cases of GTPCH deficiency (>90% of cases are caused by autosomal dominant GTPCH defi ciency). BH4 synthesis is greatly reduced, which leads to dopamine and serotonin deficiency. Supplementation of BH4 is necessary for treatment. Doses of 1–10 mg/kg daily raise phenylalanine hydroxylase activity in the liver, which results in normalisation of phenylalanine levels. The amount of BH4 entering the brain is not sufficient to sustain appropriate synthesis of neurotransmitters. Precursors of the monoamines (levodopa and 5-hydroxytryptophan) and monoamine oxidase inhibitors (eg, selegiline, tranylcypromine, and moclobemide) are, therefore, also frequently required Thony B, Blau N. Mutations in the BH4-Metabolizing Genes GTP Cyclohydrolase I, 6-Pyruvoyl-Tetrahydropterin Synthase, Sepiapterin Reductase, Carbinolamine-4a- Dehydratase, and Dihydropteridine Reductase. Hum Mutat 27(9), 870–878, 2006 Sato H et al. Early replacement therapy in a first Japanese case with autosomal recessive GTPCH 1 deficiency with a novel point mutation. Brain Dev May 6. pii: S0387-Bruggemann N et al. Beneficial Prenatal Levodopa Therapy in Autosomal Recessive Guanosine Triphosphate Cyclohydrolase 1 Deficiency. Arch Neurol. 2012;69(8): Kurian MA, et al. The monoamine neurotransmitter disorders: an expanding range of neurological syndromes. Lancet Neurol 2011; 10: 721–33

50 We describe a unique presentation of autosomal recessive (AR) GTP cyclohydrolase I (GTPCH) deficiency, with severe CNS involvement but without hyperphenylalaninemia. A male infant presented with progressive spasticity, dystonia and oculogyric episodes. Blood phenylalanine levels were persistently normal: whereas an oral phenylalanine loading test revealed impaired phenylalanine clearance. CSF neopterin and tetrahydrobiopterin (BH4) were low, homovanillic acid marginally low and 5-hydroxyindoleacetic acid normal. Fibroblasts showed decreased GTPCH enzyme activity. A homozygous novel mutation of GCH1, p.V206A, was identified. On treatment (BH4, L-Dopa/Carbidopa and 5-hydroxytryptophan), motor development improved. Mutational analysis provided neonatal diagnosis of a younger brother who, after 18 months on treatment, shows normal development. AR GTPCH I deficiency can present without hyperphenylalaninemia and with normal or subtle CSF neurotransmitter profiles. Testing for GTPCH deficiency should be considered for patients with unexplained neurological symptoms and extrapyramidal movement disorder.

51 Déficit de GTPCH autosómica recesivaDefecto del metabolismo de las pterinas con HFA Déficit de GTPCH autosómica recesiva B.1 Diagnóstico Tratamiento La mayoría en screening neonatal por HFA ↓ biopterina y neopterina en orina LCR: ↓ HVA, 5-HIAA y pterinas Medición de actividad de enzima puede ser útil para confirmar el diagnóstico Identificación de mutación en GCH1 homocigota o heterocigota compuesta Suplementación BH4 Dosis 1-10 mg/kg/d aumentan la actividad de la fenialanina hidroxilasa hepática normalización niveles fenilalanina Cantidad que ingresa al cerebro es insuficiente para síntesis de NT L-dopa y 5-hidroxitriptofano Inhibidores de monoamino oxidasa Most patients are identified by the presence of hyperphenylalaninaemia in neonatal blood spot screening. Biopterin and neopterin concentrations in urine are low, as are concentrations of HVA, 5-HIAA, and pterins in CSF. Measurement of enzyme activity can be helpful to confirm the diagnosis. Patients have homozygous or compound heterozygous mutations in GCH1 (OMIM *600225). Autosomal recessive GTPCH deficiency accounts for less than 10% of cases of GTPCH deficiency (>90% of cases are caused by autosomal dominant GTPCH defi ciency). BH4 synthesis is greatly reduced, which leads to dopamine and serotonin deficiency. Supplementation of BH4 is necessary for treatment. Doses of 1–10 mg/kg daily raise phenylalanine hydroxylase activity in the liver, which results in normalisation of phenylalanine levels. The amount of BH4 entering the brain is not sufficient to sustain appropriate synthesis of neurotransmitters. Precursors of the monoamines (levodopa and 5-hydroxytryptophan) and monoamine oxidase inhibitors (eg, selegiline, tranylcypromine, and moclobemide) are, therefore, also frequently required MENCIONAR QUE HAY REPORTES DE CASOS DE SUPLEMENTACIÓN PRENATAL Kurian MA, et al. The monoamine neurotransmitter disorders: an expanding range of neurological syndromes. Lancet Neurol 2011; 10: 721–33 Bruggemann N et al. Beneficial Prenatal Levodopa Therapy in Autosomal Recessive Guanosine Triphosphate Cyclohydrolase 1 Deficiency. Arch Neurol. 2012;69(8):

52 Déficit de 6-piruvoil-tetrahidropterina sintasa (PTPS)Defecto del metabolismo de las pterinas con HFA Déficit de 6-piruvoil-tetrahidropterina sintasa (PTPS) B.2 Trastorno más frecuente del metabolismo de BH4 Forma más prevalente y heterogénea de HFA no atribuida a deficiencia de fenilalanina oxidasa Frecuente pesquisa en screening neonatal Fenotipo PKU+ manifestaciones neurológicas de déficit de monoaminas Mutación gen PTS (cr 11q22.3- q23.3) 2 presentaciones: forma típica/severa vs atípica/periférica Asn52Ser and Pro87Ser are most frequent in Asian populations. Good genotype–phenotype correlations are apparent: specific mutations seem to cause mild phenotypes that are associated with high residual enzyme activity. The severe phenotype seems to arise from genetic mutations that cause a nucleotide frameshift (and subsequent major alterations in coding sequence) or altered protein zinc binding or oligomerisation. Loss of PTPS activity substantially lessens BH4 synthesis and leads to impairment of dopamine and serotonin production (figure 2). Kurian MA, et al. The monoamine neurotransmitter disorders: an expanding range of neurological syndromes. Lancet Neurol 2011; 10: 721–33 Pearl PL. Monoamine neurotransmitter deficiencies. Handb Clin Neurol. 2013;113:

53 Déficit de PTPS: fisiopatologíaDefecto del metabolismo de las pterinas con HFA Déficit de PTPS: fisiopatología B.2 Mutación gen PTS (cr 11q22.3- q23.3) 6 exones >50 mutaciones descritas, alta heterogeneidad alélica Aparente buena relación genotipo- fenotipo 2/3 asociadas con forma severa Fenotipo severo: cambio de marco de lectura o alteración de unión de proteína a zinc o de oligomerización Pérdida de actividad PTPS disminuye sustancialmente niveles BH4 alteración producción de dopamina y serotonina Asn52Ser and Pro87Ser are most frequent in Asian populations. Good genotype–phenotype correlations are apparent: specific mutations seem to cause mild phenotypes that are associated with high residual enzyme activity. The severe phenotype seems to arise from genetic mutations that cause a nucleotide frameshift (and subsequent major alterations in coding sequence) or altered protein zinc binding or oligomerisation. Loss of PTPS activity substantially lessens BH4 synthesis and leads to impairment of dopamine and serotonin production (figure 2). Thony B, Blau N. Mutations in the BH4-Metabolizing Genes GTP Cyclohydrolase I, 6-Pyruvoyl-Tetrahydropterin Synthase, Sepiapterin Reductase, Carbinolamine-4a- Dehydratase, and Dihydropteridine Reductase. Hum Mutat 27(9), 870–878, 2006 Kurian MA, et al. The monoamine neurotransmitter disorders: an expanding range of neurological syndromes. Lancet Neurol 2011; 10: 721–33 Pearl PL. Monoamine neurotransmitter deficiencies. Handb Clin Neurol. 2013;113:

54 Déficit de PTPS: ClínicaDefecto del metabolismo de las pterinas con HFA Déficit de PTPS: Clínica B.2 Forma leve (20%) Curso neurológico normal Pronóstico excelente Forma severa (80%) Compromiso neurológico RNPT y BPN LCR con HVA y 5-HIAA normal LCR con HVA y 5-HIAA bajo Inicio en periodo lactante Inicial hipotonía axial, luego hipertonía apendicular, bradikinesia, rigidez en rueda dentada, distonía generalizada y marcada fluctuación diurna También dificultades en deglución, crisis oculógiras, somnolencia, irritabilidad, hipertermia y crisis generalizada, coreoatetosis, hipersalivación, rash con eczema y muerte súbita Síntomas neuropsiquiátricos With the severe form there is an increased risk of prematurity and low birth weight. In most cases, however, children appear normal at birth and present with abnormal movements and delayed developmental milestones in the first few months of life. Patients with the peripheral form usually have an excellent prognosis for normal neurological development, as long as the hyperphenylalaninaemia is corrected by diet or administration of BH4. Patients are classified as having mild and peripheral or severe and generalised disease on the basis, respectively, of normal (<20% of clinical cases) or abnormally low (>80% of clinical cases) concentrations of HVA and 5-HIAA in CSF. Most patients with mild disease have a normal neurological course and excellent prognosis. Severe phenotypes, however, are associated with neurological impairment (dystonia, athetosis, hypotonia, hypokinesia, rigidity, tremor, oculogyric crises, seizures, irritability, and developmental delay) in early infancy, as well as premature birth and low birthweight. Some patients with severe phenotypes also develop neuropsychiatric features, such as obsessive-compulsive disorder, panic attacks, and depression. Hyperphenylalaninaemia is frequently found in neonatal blood spot screening. In urine, biopterin concentrations are reduced and those of neopterin are increased.33 In CSF, neopterin concentration is high, but levels of other pterin metabolites, HVA, and 5-HIAA are low. Prolactin concentrations in serum might be raised. PTPS deficiency is caused by mutations in PTS (OMIM *612719) on chromosome 11q22.3–q23.3. More than 50 mutations have been described, with high allelic heterogeneity.50 Asn52Ser and Pro87Ser are most frequent in Asian populations. Good genotype–phenotype correlations are apparent: specific mutations seem to cause mild phenotypes that are associated with high residual enzyme activity. The severe phenotype seems to arise from genetic mutations that cause a nucleotide frameshift (and subsequent major alterations in coding sequence) or altered protein zinc binding or oligomerisation.59 Loss of PTPS activity substantially lessens BH4 synthesis and leads to impairment of dopamine and serotonin production (figure 2). Treatment strategies are similar to those for autosomal recessive GTPCH defi ciency. In patients with severe disease, outcomes are thought to be improved by early treatment (within 1 month of diagnosis). Brasil and colleagues have shown proof of concept for use of pseudoexon-exclusion therapy with antisense morpholino oligonucleotides in cell lines from three PTPS-deficient patients with intronic mutations resulting in splicing defects. Transcriptional profiling (24 h after transfection) revealed dose-specific and sequence-specific recovery of normal splicing. PTPS enzyme activity in fibroblasts from all three patients and the pterin profiles were close to normal after treatment. Kurian MA, et al. The monoamine neurotransmitter disorders: an expanding range of neurological syndromes. Lancet Neurol 2011; 10: 721–33 Pearl PL. Monoamine neurotransmitter deficiencies. Handb Clin Neurol. 2013;113:

55 Déficit de PTPS: EstudioDefecto del metabolismo de las pterinas con HFA Déficit de PTPS: Estudio B.2 HFA en test gota de sangre frecuente En orina ↓ biopterina, ↑ neopterina Puede haber ↑ prolactina en sangre LCR ↑ neopterina ↓ otros metabolitos biopterinas, HVA y 5-HIAA Kurian MA, et al. The monoamine neurotransmitter disorders: an expanding range of neurological syndromes. Lancet Neurol 2011; 10: 721–33 Niu D-M. Disorders of BH4 metabolism and the treatment of patients with 6-pyruvoyl-tetrahydropterin synthase deficiency in Taiwan. Brain Dev. 2011;33(10):847-55 Pearl PL. Monoamine neurotransmitter deficiencies. Handb Clin Neurol. 2013;113:

56 Déficit de PTPS: TratamientoDefecto del metabolismo de las pterinas con HFA Déficit de PTPS: Tratamiento B.2 Administración BH4 Normaliza niveles de fenilalanina Iniciar con 2 mg/kg/d y ajustar para mantener [PHE] <120 uM No cruza BHE Asociado a L-DOPA y 5- hidroxitriptofano Dosis óptima difícil de determinar Precaución con efectos secundarios L-dopa inicio con 2 mg/kg/d ↑1mg c/2-5 días Target 10-15mg/kg/d 5Hidroxitriptofano inicio 1mg/kg/d ↑1mg c/2-5 días Target 5mg/kg/d Outcome: Between 1988 and 2000, 12 newborns with PTPS deficiency identified by newborn screening were referred and received early treatment at our hospital. The mean IQ score of these 12 patients was 96.7 (±9.7; range: 86–119), which is considerably higher than previous reports of other populations of PTPS-deficient patients. In this report, we reviewed the disorders of BH4 briefly and then described treatments of our PTPS-deficient patients Serie Taiwanesa (n=12) CI 96.7 (±9.7; rango: 86–119) Serie italiana (n=19) Forma leve (n=6): DSM normal Forma severa (n=13) 12 compromiso neurológico grave, DSM normal 4/13 Outcome Forma severa de la enfermedad: outcome mejora si tratamiento se inicia precozmente Kurian MA, et al. The monoamine neurotransmitter disorders: an expanding range of neurological syndromes. Lancet Neurol 2011; 10: 721–33 Niu D-M. Disorders of BH4 metabolism and the treatment of patients with 6-pyruvoyl-tetrahydropterin synthase deficiency in Taiwan. Brain Dev. 2011;33(10):847-55 Leuzzi V et al. Phenotypic variability, neurological outcome and genetics background of 6-pyruvoyl-tetrahydropterin synthase deficiency. Clin Genet 2010: 77: 249–257

57 Déficit de dihidropteridina reductasa (DHPR)Defecto del metabolismo de las pterinas con HFA Déficit de dihidropteridina reductasa (DHPR) B.3 Defecto en la regeneración de BH4 luego de la hidroxilación de sustratos y la acción de la carbinolamina dehidratasa ↓ BH4 ↓ serotonina y dopamina Usualmente detectada en screening neonatal por HFA Clínicamente es más severa que otros trastornos del metabolismo de las pterinas RDSM pese a tratamiento Causado por mutación en gen QDPR (4p15.31) >34 mutaciones descritas Buena relación genotipo-fenotipo In dihydropteridine reductase deficiency, there are basal ganglia calcifications that are reversible with folinic acid supplementation The natural course of DHPR deficiency (OMIM #261630) is thought to be more severe than that of other disorders of pterin metabolism. Onset is in the neonatal period or early infancy and is associated with feeding difficulties, bulbar dysfunction, hypersalivation, and microcephaly. Patients develop delayed motor and cognitive milestones, truncal and limb hypertonia, dyskinesia, tremor, dystonia, choreoathetosis, and seizures. Patients with DHPR deficiency are at increased risk of sudden death. This disorder should be suspected in babies with hyperphenylalaninaemia identified through neonatal blood spot screening. DHPR enzyme activity measured in blood spots is markedly reduced. Concentrations of HVA, 5-HIAA, and folate are low and biopterin concentration is raised in CSF. BH4 deficiency is not always seen. White-matter abnormalities and basal ganglia calcification might be evident on brain MRI. DHPR deficiency is caused by mutations in QDPR (OMIM *612676) on chromosome 4p Some mutations have been described. Two mutations (Gly151Ser and Phe2112Cys) are associated with mild disease presentations, associated with selective impairment of serotonin metabolism. DHPR deficiency results from a defect in the salvage pathway necessary for the regeneration of BH4 after hydroxylation of substrates and the action of carbinolamine dehydratase (figure 2). A subsequent deficiency in regenerated BH4, as well as the inhibitory effect of accumulated q-dihydrobiopterin on AADC, phenylalanine hydroxylase, tyrosine hydroxylase, and tryptophan hydroxlyase, results in hyper phenyl alaninaemia and reduced production of dopamine and serotonin. Neurological impairment might also be attributable to depleted folate concentrations in the brain, owing to the importance of DHPR in maintaining folate in its active form; this feature is thought to raise the risk of sudden death. Accumulated q-dihydro biopterin could also alter folic acid concentrations. Patients with DHPR deficiency require supplementation with BH4, and some severely affected children also need dietary restriction of phenylalanine to normalise concentrations. Neurotransmitter precursors (levodopa and 5-hydroxytryptophan) and other agents, such as monoamine oxidase inhibitors (eg, selegiline, tranylcypromine, and moclobemide), are frequently required. All doses should be started low and increased gradually to therapeutic levels to keep to a minimum the risk of dyskinesias and intolerance. Treatment with folinic acid is also recommended to counteract the depletion of folate caused by the disease and by levodopa therapy and, ultimately, to prevent secondary 5-methyltetra hydrofolate deficiency. Good clinical outcomes can be achieved, especially if treatment is started early in the disease course. Longo N. Disorders of biopterin metabolism. J Inherit Metab Dis (2009) 32:333–342 Kurian MA, et al. The monoamine neurotransmitter disorders: an expanding range of neurological syndromes. Lancet Neurol 2011; 10: 721–33 Thony B, Blau N. Mutations in the BH4-Metabolizing Genes GTP Cyclohydrolase I, 6-Pyruvoyl-Tetrahydropterin Synthase, Sepiapterin Reductase, Carbinolamine-4a- Dehydratase, and Dihydropteridine Reductase. Hum Mutat 27(9), 870–878, 2006

58 Déficit de DHPR: Clínica y diagnósticoDefecto del metabolismo de las pterinas con HFA Déficit de DHPR: Clínica y diagnóstico B.3 Inicio en periodo RN o infancia precoz: dificultades para alimentarse, disfunción bulbar, hipersalivación, microcefalia Evolucionan con RDSM, hipertonía tronco y miembros, diskinesias, temblor, distonía, coreoatetosis y convulsiones Mayor riesgo de muerte súbita Prueba de la gota de sangre RN: HPA ↓ Actividad DHPR marcadamente LCR: ↓ HVA, 5-HIAA y folato, ↑biopterina. No siempre déficit BH4 RNM: se puede ver alteraciones SB y calcificaciones de ganglios basales Reversibles con suplementación de ácido folínico Neurological impairment might also be attributable to depleted folate concentrations in the brain, owing to the importance of DHPR in maintaining folate in its active form; this feature is thought to raise the risk of sudden death. Accumulated q-dihydro biopterin could also alter folic acid concentrations. DHPR mantiene folato en su forma activa, ↑q-BH2  ↓folato en cerebro Deterioro neurológico también atribuible a ↓ folato en cerebro Longo N. Disorders of biopterin metabolism. J Inherit Metab Dis (2009) 32:333–342 Kurian MA, et al. The monoamine neurotransmitter disorders: an expanding range of neurological syndromes. Lancet Neurol 2011; 10: 721–33

59 Déficit de DHPR: TratamientoDefecto del metabolismo de las pterinas con HFA Déficit de DHPR: Tratamiento B.3 Suplementación BH4 Restricción PHE en la dieta Precursores de monoaminas (l-dopa y 5-hidroxitriptofano) IMAOs (selegilina, etc) Suplementar ácido folínico Patients with DHPR deficiency require supplementation with BH4, and some severely affected children also need dietary restriction of phenylalanine to normalise concentrations. Neurotransmitter precursors (levodopa and 5-hydroxytryptophan) and other agents, such as monoamine oxidase inhibitors (eg, selegiline, tranylcypromine, and moclobemide), are frequently required. All doses should be started low and increased gradually to therapeutic levels to keep to a minimum the risk of dyskinesias and intolerance. Treatment with folinic acid is also recommended to counteract the depletion of folate caused by the disease and by levodopa therapy and, ultimately, to prevent secondary 5-methyltetra hydrofolate deficiency. Good clinical outcomes can be achieved, especially if treatment is started early in the disease course. Many patients have significant developmental delays despite therapy, develop brain abnormalities, and are prone to sudden death. The reason is not completely clear, but might be related to the accumulation of q-dihydrobiopterin (BH2) and abnormal metabolism of folic acid. Accumulated BH2 inhibits all enzymes using tetrahydrobiopterin (BH4) as cofactor. Se ha registrado buen pronóstico con tratamiento precoz Longo N. Disorders of biopterin metabolism. J Inherit Metab Dis (2009) 32:333–342 Kurian MA, et al. The monoamine neurotransmitter disorders: an expanding range of neurological syndromes. Lancet Neurol 2011; 10: 721–33

60 Déficit de Pterin-4α-carbinolamina dehidratasa (PCD)Defecto del metabolismo de las pterinas con HFA Déficit de Pterin-4α-carbinolamina dehidratasa (PCD) B.4 Se requiere para la regeneración de BH4 Mutación gen PCDB 10q22 9 mutaciones descritas En RN HPA leve con ↑ 7 biopterina persistentemente en orina PHE se normaliza Se ha reportado hipotonía neonatal transitoria, la mayoría asintomática La mayoría no desarrolla síntomas o signos neurológicos, no se detecta alteraciones NT Pronóstico excelente en general Although transient neonatal hypotonia owing to pterin-4α-carbinolamine dehydratase deficiency (OMIM #264070) has been reported in some patients, most develop no neurological symptoms or signs and neurotransmitter abnormalities are not detected.33 The clinical outcome is generally excellent. Pterin-4!-carbinolamine dehydratase (PCD) is required for the regeneration of tetrahydrobiopterin after phenylalanine hydroxylation (Fig. 2). Deficiency of this activity causes in newborns a mild form of hyperphenylalaninaemia (HPA) with persistent high urinary levels of primapterin (7-biopterin). Affected patients appear completely normal, but have elevated phenylalanine levels at birth. Most patients develop no symptoms, although transient hypotonia has been reported in some. In most patients, phenylalanine levels normalize after few months of life and remain normal or just above the normal range with an unrestricted diet. The reason for this normalization is not completely clear, although it is likely that other enzymes with the same enzymatic activity (such as the recently proposed pterin-4!-carbinolamine dehydratase/DCoHalpha) become able to compensate later in life (Hevel et al 2006). Neurotransmitter levels are not altered in this condition and the outcome of these patients is usually excellent. Pterin-4!-carbinolamine dehydratase can dimerize with HNF-1a and work as a transcription factor. However, there are no known abnormalities related to this function, probably because there are other genes encoding very similar proteins. The PCDB gene is composed of 4 exons on 10q22 and 9 different mutations have been identified in affected patients (Tho¨ ny and Blau 2006). Longo N. Disorders of biopterin metabolism. J Inherit Metab Dis (2009) 32:333–342 Kurian MA, et al. The monoamine neurotransmitter disorders: an expanding range of neurological syndromes. Lancet Neurol 2011; 10: 721–33 Thony B, Blau N. Mutations in the BH4-Metabolizing Genes GTP Cyclohydrolase I, 6-Pyruvoyl-Tetrahydropterin Synthase, Sepiapterin Reductase, Carbinolamine-4a- Dehydratase, and Dihydropteridine Reductase. Hum Mutat 27(9), 870–878, 2006

61 Resumiendo Campeau PM, et al. Neurotransmitter diseases and related conditions. Mol Genet Metab Nov;92(3):189-97

62 Resumiendo En nuestra paciente: antecedente familiar de trastorno de la marcha en 3 generaciones, en familiares de primera línea. Inversión y rotación interna de EEII, con fluctuaciones diurnas que inició a los 9 años Campeau PM, et al. Neurotransmitter diseases and related conditions. Mol Genet Metab Nov;92(3):189-97

63 Conclusiones Grupo de trastornos neurológicos en expansiónMuchos se presentan en periodo lactante o infancia precoz Importante reconocerlos porque frecuentemente se diagnostican erroneamente y muchos tienen buena respuesta clínica a tratamiento Descripción de espectro fenotípico ha mejorado por mayor conciencia de los clínicos, tests bioquímicos más confiables, tests genético moleculares han mejorado

64

65 BH4 Y PKU

66 BH4 y PKU ¿A quienes tratar? BH4 actúa como cofactor de PAHHerramienta terapéutica reciente para manejo PKU 20-56% pacientes con PKU responden a BH4 Se ha visto mejor respuesta en fenotipos leves (80%) que severos Mutaciones especificas con actividad enzimática residual son buen indicador de respuesta a BH4. Zurfluh, Molecular Genetics of Tetrahydrobiopterin- Responsive Phenylalanine Hydroxylase Deficiency. HUMAN MUTATION 29(1),167^175,2008 Staudigl, The interplay between genotype, metabolic state and cofactor treatment governs phenylalanine hydroxylase function and drug response. Human Molecular Genetics, 2011, Vol. 20, No. 13