Research progress on renal calculus associate with inborn error of metabolism / 浙江大学学报·医学版

Renal calculus is a common disease with complex etiology and high recurrence rate. Recent studies have revealed that gene mutations may lead to metabolic defects which are associated with the formation of renal calculus, and single gene mutation is involved in relative high proportion of renal calculus. Gene mutations cause changes in enzyme function, metabolic pathway, ion transport, and receptor sensitivity, causing defects in oxalic acid metabolism, cystine metabolism, calcium ion metabolism, or purine metabolism, which may lead to the formation of renal calculus. The hereditary conditions associated with renal calculus include primary hyperoxaluria, cystinuria, Dent disease, familial hypomagnesemia with hypercalciuria and nephrocalcinosis, Bartter syndrome, primary distal renal tubular acidosis, infant hypercalcemia, hereditary hypophosphatemic rickets with hypercalciuria, adenine phosphoribosyltransferase deficiency, hypoxanthine-guanine phosphoribosyltransferase deficiency, and hereditary xanthinuria. This article reviews the research progress on renal calculus associated with inborn error of metabolism, to provide reference for early screening, diagnosis, treatment, prevention and recurrence of renal calculus.

Clinical and molecular genetic analysis of a case of MEGDEL syndrome / 中华医学遗传学杂志

OBJECTIVE@#To explore the clinical and genetic characteristics of a child with MEGDEL syndrome.@*METHODS@#Clinical data of the child was reviewed. Peripheral blood samples of the child and his parents were collected. Mitochondrial genome and the whole exome of the child were analyzed by next-generation sequencing. Candidate variants and its origin were verified by Sanger sequencing and fluorescence quantitative PCR.@*RESULTS@#The patient, a 2-year-and-6-month-old male, has featured hypoglycemia, mental and motor retardation with regression. Cranial MRI showed bilateral putamen damage suggestive of Leigh syndrome. Testing of urine organic acid indicated that the level of 3-methylpentenoic acid was slightly increased. Whole exome sequencing revealed that the child has harbored heterozygous deletion of exons 6 to 17 and c.307A>T nonsense variant of the SERAC1 gene, which were respectively inherited from his parents who were asymptomatic. Treatment with Levocarnitine, vitamin B1, vitamin B2, coenzyme Q10, baclofen and glucuronolactone resulted in improvement of sleep and mental state.@*CONCLUSION@#A case of MEGDEL syndrome without deafness was diagnosed. Discovery of the nonsense mutation and large fragment deletion have enriched the spectrum of SERAC1 gene variants.

Analysis of gene variant in a Chinese child affected with dihydropyrimidinase deficiency / 中华医学遗传学杂志

OBJECTIVE@#To analyze the molecular etiology of a Chinese child affected with dihydropyrimidinase deficiency.@*METHODS@#Genomic DNA was extracted from peripheral blood samples of the family members. Pathogenic variant was determined by whole exome sequencing and verified by Sanger sequencing.@*RESULTS@#The child was found to harbor homozygous c.905G>A (p.Arg302Gln) variants in exon 5 of the DPYS gene, for which her parents were both heterozygous carriers.@*CONCLUSION@#The homozygous c.905G>A (p.Arg302Gln) variants of the DPYS gene probably underlies the dihydropyrimidinase deficiency in the child. Above result has enabled genetic counseling and prenatal diagnosis for this family.

Changes in temporomandibular joint anatomy, changes in condylar translation, and their relationship with disc displacement: magnetic resonance imaging study / Ressonância magnética das alterações anatômicas e translação condilar da articulação temporomandibular e suas relações com o deslocamento do disco

Abstract Objective: To assess changes in the articular surfaces of the temporomandibular joint (TMJ) and in condylar translation, as detected by magnetic resonance imaging (MRI), determining whether such changes correlate with disc displacement. Materials and Methods: We retrospectively analyzed the MRI scans of 2076 TMJs of 1038 patients with symptoms of temporomandibular disorder. We attempted to determine whether articular disc deformity and changes in condylar translation, as well as changes in the articular surfaces of the condyle, glenoid fossa, and articular eminence, correlated with disc displacement. Results: Disc displacement with reduction was associated with changes in the shape of the articular eminence. Disc displacement without reduction was most strongly associated with disc deformity, condylar degeneration, glenoid fossa degeneration, and effusion. Neither decreases nor increases in condylar translation were associated with disc deformity, degenerative bone changes, or disc displacement. Conclusion: Changes in the shape of the articular eminence seem to predispose to progression of internal derangement of the TMJ.

Resumo Objetivo: Verificar a correlação entre as alterações das superfícies articulares e da translação condilar com o deslocamento de disco da articulação temporomandibular. Materiais e Métodos: Foram analisados os exames de ressonância magnética de 2076 articulações temporomandibulares de pacientes sintomáticos de desordens temporomandibulares. A deformidade do disco articular, as alterações nas superfícies articulares do côndilo, da fossa glenoide e da eminência articular e as alterações na translação condilar foram correlacionadas com o deslocamento do disco. Resultados: O deslocamento do disco com redução demonstrou associação com as alterações de forma da eminência articular. O deslocamento do disco sem redução apresentou maior associação com a deformidade do disco, degeneração do côndilo e da fossa glenoide e efusão. Diminuição e aumento da translação condilar não apresentaram associação com a deformidade do disco, com alterações ósseas degenerativas, nem com o deslocamento do disco. Conclusão: Mudanças na forma da eminência articular parecem predispor à progressão do desarranjo interno da articulação temporomandibular.

Colestasis por deficiencia de 3β-Δ5-C27-hidroxiesteroide deshidrogenasa en un paciente con alteración en la síntesis de ácidos biliares / Cholestasis due to deficiency of 3β-Δ5-C27-hydroxysteroid dehydrogenase in a patient with altered bile acid synthesis

Resumen: Introducción: Los errores innatos en la síntesis de ácidos biliares son un grupo de defectos genéticos que representan del 1 al 2% de las enfermedades colestásicas crónicas en lactantes, niños y adolescentes. La deficiencia de 3β-Δ5-C27-hidroxiesteroide oxidoreductasa (3β-HSDH) es el defecto más comúnmente reportado. El cuadro clínico característico consiste en hepatitis neonatal, hepatomegalia, esplenomegalia, malabsorción, desnutrición y enfermedad hepática de aparición tardía. Caso clínico: Lactante masculino con antecedente de ictericia en escleras a los 4 meses que se resolvió espontáneamente; posteriormente, a los 18 meses, presentó enfermedad colestásica. Durante su abordaje se documentó gamma-glutamil transpeptidasa normal, hallazgo que es altamente sugestivo de alteración en la síntesis de ácidos biliares. El diagnóstico se realizó con espectrometría de masas en orina. Se inició tratamiento con ácido cólico oral, y presentó mejoría inmediata. Conclusiones: El resultado en los ácidos biliares urinarios es definitivo para el defecto genético y consistente con mutaciones homocigotas en el gen HSD3B7. Este padecimiento constituye un diagnóstico de exclusión en las enfermedades colestásicas de la infancia, particularmente el hallazgo de gamma-glutamil transpeptidasa normal o levemente aumentada, y responde adecuadamente al tratamiento oral, por lo que debe identificarse de forma temprana.

Abstract: Background: Inborn errors in bile acid synthesis are a group of genetic defects accounting for 1 to 2% of chronic cholestatic diseases in infants, children and adolescents. Deficiency of 3β-Δ5-C27-hydroxysteroid dehydrogenase (3β-HSDH) is the most common defect in this disease. Clinical features consist of neonatal hepatitis, hepatomegaly, splenomegaly, malabsorption, malnutrition, and late-onset liver disease. Case report: A male infant who presented jaundice in sclera at 4 months that resolved spontaneously, later presented cholestatic disease at 18 months. During his approach, normal gamma-glutamyl transpeptidase was documented, a finding that is highly suggestive of alteration in the synthesis of bile acids. The diagnosis was made using urine mass spectrometry. Oral colic acid treatment was started, presenting immediate improvement. Conclusions: The result in urinary bile acids is definitive for the genetic defect and consistent with homozygous mutations in the HSD3B7 gene. This condition is a diagnosis of exclusion in childhood cholestatic diseases, particularly in the presence of normal or mildly enlarged gamma-glutamyl transpeptidase, and responds adequately to oral treatment; it should be identified early.

NR3C1 polymorphisms in Brazilians of Caucasian, African, and Asian ancestry: glucocorticoid sensitivity and genotype association / Polimorfismos NR3C1 em brasileiros de ascendência caucasiana, africana e asiática: sensibilidade aos glicocorticoides e associação de genótipos

Objective : The Brazilian population has heterogeneous ethnicity. No previous study evaluated NR3C1 polymorphisms in a Brazilian healthy population. Materials and methods : We assessed NR3C1 polymorphisms in Brazilians of Caucasian, African and Asian ancestry (n = 380). In a subgroup (n = 40), we compared the genotypes to glucocorticoid (GC) sensitivity, which was previously evaluated by plasma (PF) and salivary (SF) cortisol after dexamethasone (DEX) suppression tests, GC receptor binding affinity (K d ), and DEX-50% inhibition (IC 50 ) of concanavalin-A-stimulated mononuclear cell proliferation. p.N363S (rs6195), p.ER22/23EK (rs6189-6190), and BclI (rs41423247) allelic discrimination was performed by Real-Time PCR (Polymerase Chain Reaction). Exons 3 to 9 and exon/intron boundaries were amplified by PCR and sequenced. Results : Genotypic frequencies (%) were: rs6195 (n = 380; AA:96.6/AG:3.14/GG:0.26), rs6189-6190 (n = 264; GG:99.6/GA:0.4), rs41423247 (n = 264; CC:57.9/CG:34.1/GG:8.0), rs6188 (n = 155; GG:69.6/GT:25.7/TT:4.7), rs258751 (n = 150; CC:88.0/CT:10.7/TT:1.3), rs6196 (n = 176; TT:77.2/TC:20.4/CC:2.4), rs67300719 (n = 137; CC:99.3/CT:0.7), and rs72542757 (n = 137; CC:99.3/CG:0.7). The rs67300719 and rs72542757 were found only in Asian descendants, in whom p.N363S and p.ER22/23EK were absent. The p.ER22/23EK was observed exclusively in Caucasian descendants. Hardy-Weinberg equilibrium was observed, except in the Asian for rs6188 and rs258751, and in the African for p.N363S. The K d , IC 50 , baseline and after DEX PF or SF did not differ between genotype groups. However, the mean DEX dose that suppressed PF or SF differed among the BclI genotypes (P = 0.03). DEX dose was higher in GG- (0.7 ± 0.2 mg) compared to GC- (0.47 ± 0.2 mg) and CC-carriers (0.47 ± 0.1 mg). Conclusion : The genotypic frequencies of NR3C1 polymorphisms in Brazilians are similar to worldwide populations. Additionally, the BclI polymorphism ...

Objetivo : Este estudo avalia polimorfismos (SNPs) do NR3C1 na população brasileira, que possui origem étnica heterogênea. Materiais e métodos : SNPs do NR3C1 foram avaliados em brasileiros de ancestralidade caucasiana, africana ou japonesa (n = 380). Em um subgrupo (n = 40), os genótipos foram comparados à sensibilidade aos glicocorticoides (GC), previamente avaliada por cortisol plasmático (PF) e salivar (SF) após supressão com dexametasona (DEX), ensaio de afinidade do receptor ao GC (K d ) e inibição por DEX de 50% da proliferação de mononucleares estimulada por concanavalina-A (IC 50 ). Discriminação alélica de p.N363S (rs6195), p.ER22/23EK (rs6189-6190) e BclI (rs41423247) foi realizada por PCR em tempo real. Éxons 3 a 9 e transições éxon/íntron foram amplificados e sequenciados. Resultados : Frequências genotípicas (%) foram: rs6195 (n = 380; AA:96,6/AG:3,14/GG:0,26), rs6189-6190 (n = 264; GG:99,6/GA:0,4), rs41423247 (n = 264; CC:57,9/CG:34,1/GG:8,0), rs6188 (n = 155; GG:69,6/GT:25,7/TT:4,7), rs258751 (n = 150; CC:88,0/CT:10,7/TT:1,3), rs6196 (n = 176; TT:77,2/TC:20,4/CC:2,4), rs67300719 (n = 137; CC:99,3/CT:0,7), e rs72542757 (n = 137; CC:99,3/CG:0,7). Enquanto rs67300719 e rs72542757 foram exclusivos dos nipodescendentes, p.N363S e p.ER22/23EK estavam ausentes nesses indivíduos. p.ER22/23EK foi exclusivo dos descendentes de caucasianos. Equilíbrio de Hardy-Weinberg foi observado, exceto nos nipodescendentes para rs6188 e rs258751 e nos afrodescendentes para p.N363S. K d , IC 50 , PF ou SF basal ou após DEX foram semelhantes entre os genótipos. Entretanto, a dose média de DEX que suprimiu PF ou SF diferiu entre os genótipos BclI (P = 0,03), sendo maior nos carreadores GG (0,7 ± 0,2 mg) comparada aos GC (0,47 ± 0,2 mg) e CC (0,47 ± 0,1 mg). Conclusão : As ...

Coexistence of glucocorticoid resistance and pseudohypoparathyroidism / Coexistencia de la resistencia a glucocorticoides y el pseudohipoparatiroidismo

We report for the first time the case of a young man who developed both glucocorticoid resistance and resistance to parathyroid hormone. Treatment with high doses of dexamethasone together with administration of calcium and calcitriol resulted in a significant improvement in the patient's condition. In this paper, we discuss in detail diagnostic and treatment strategies used on the patient and the impact on the course and outcome of both disorders. We associate the development of both these disorders with a possible inherited defect in the signal pathways common to glucocorticoid and parathyroid hormone receptors.

Por primera vez se reporta el caso de un joven que desarrolló resistencia a glucocorticoides y resistencia a la hormona paratiroidea. El tratamiento con altas dosis de dexametasona, junto con la administración de calcio y calcitriol, trajo como resultado una mejoría significativa de la condición del paciente. En este papel, se analiza en detalle el diagnóstico así como las estrategias de tratamiento del paciente, y su impacto en el curso y resultado de ambos trastornos. Se concluye que el desarrollo de ambos trastornos se halla asociado a un posible defecto hereditario en las vías de transducción de señales comunes a los receptores de las hormonas glucocorticoides y las hormonas paratiroideas.

Deficiencia de 3-hidroxiacil coA deshidrogenasa de cadena larga, asociación con HELLP y hallazgos en la espectroscopia por resonancia magnética / Long chain 3-hydroxyacyl-coA dehydrogenase deficiency, asociation with HELLP and magnetic resonance spectroscopy findings

La deficiencia de 3-hidroxiacil coA deshidrogenasa de cadena larga (LCHAD) es uno de los trastornos de la betaoxidación de ácidos grasos. La presentación clínica más frecuente incluye trastornos de conciencia, hipoglucemia y disfunción hepática gatillados por ayuno prolongado o infecciones. Una vez desencadenada, la crisis metabólica presenta alta mortalidad. El síndrome HELLP y la hepatitis grasa aguda del embarazo (AFLP) son trastornos del tercer trimestre del embarazo. Se ha asociado estas enfermedades durante la gestación con defectos hereditarios de la betaoxidación en el feto. Comunicamos el caso clínico de un trastorno de beta oxidación (deficiencia de LCHAD) asociado a HELLP materno. Describimos como hallazgos en la resonancia magnética espectroscópica un pico de ácido láctico y lípidos significativo. La pesquisa de estos trastornos de la betaoxidación al nacimiento, ante el antecedente de HELLP materno, permite el diagnóstico de la enfermedad previo al desarrollo de los síntomas.

LCHAD deficiency is a disorder of fatty acid beta oxidation. The most common clinical presentation includes disorders of consciousness, hypoglycemia and liver dysfunction triggered by prolonged fasting or infection. Once a metabolic crisis is triggered, there is a high mortality. HELLP syndrome and acute fatty liver failure of pregnancy (AFLP) are disorders of the third trimester of pregnancy. These diseases have been associated during pregnancy with hereditary defects of beta-oxidation in the fetus. We report a case of beta-oxidation disorder (LCHAD deficiency) associated with maternal HELLP. We described a peak of lipid and lactic on magnetic resonance spectroscopic of this patient. The investigation of these beta-oxidation disorders at birth, with a history of maternal HELLP, allows the diagnosis of the disease prior to developing symptoms.

Animal models of intellectual disability: towards a translational approach

Intellectual disability is a prevalent form of cognitive impairment, affecting 2-3 percent of the general population. It is a daunting societal problem characterized by significant limitations both in intellectual functioning and in adaptive behavior as expressed in conceptual, social and practical adaptive skills. Intellectual disability is a clinically important disorder for which the etiology and pathogenesis are still poorly understood. Moreover, although tremendous progress has been made, pharmacological intervention is still currently non-existent and therapeutic strategies remain limited. Studies in humans have a very limited capacity to explain basic mechanisms of this condition. In this sense, animal models have been invaluable in intellectual disability investigation. Certainly, a great deal of the knowledge that has improved our understanding of several pathologies has derived from appropriate animal models. Moreover, to improve human health, scientific discoveries must be translated into practical applications. Translational research specifically aims at taking basic scientific discoveries and best practices to benefit the lives of people in our communities. In this context, the challenge that basic science research needs to meet is to make use of a comparative approach to benefit the most from what each animal model can tell us. Intellectual disability results from many different genetic and environmental insults. Taken together, the present review will describe several animal models of potential intellectual disability risk factors.

Erros inatos do metabolismo no Hospital das Clínicas de Ribeirão Preto: um legado de múltiplas especialidades / Inborn Errors of Metabolism - a legacy of multiple specialties

Erros inatos do metabolismo (EIM) são doenças genéticas decorrentes, em sua maioria, de deficiências enzimáticas que levam a graves distúrbios metabólicos, e que vem sendo cada vez mais diagnosticados. No presente texto relata-se um histórico sobre a evolução da abordagem diagnóstica e tratamento de EIM no HCFMRP-USP.Na FMRP-USP os EIM vêm sendo objeto de estudo em pós-graduação desde a década de 1980, dado o grande apelo clínico nas áreas de Genética Clínica, Pediatria e Neurologia Infantil, até então com auxílio do Laboratório de Patologia, além de convênio com a APAE de São Paulo para o diagnóstico de fenilcetonúria. Já iniciados os Programas de Pós-Graduação da FMRP-USP, a primeira tese a respeito foi realizada em 1980, sobre cistinúria, na Área de Genética; deficiência de glicose-6-fostato desidrogenase(G6PD) foi objetivo da segunda, em 1987, na de Pediatria. Desde essa época, garantem a rotina de investigação a realização da cromatografia de aminoácidos pelo Centro de Química de Proteínas daFMRP-USP, o convênio com o Serviço de Genética do HC de Porto Alegre-RS e a triagem urinária no Laboratório de Nutrologia, este, resultado de Mestrado em Neurologia em 1990. Nas duas últimas décadas vieram os ambulatórios especializados, o Programa de Triagem Neonatal, o tratamento por Reposição Enzimática e o apoio do Centro de Transplante de Células Tronco. Cabe ressaltar que até2009, apenas mais uma tese foi apresentada. A perpectiva para o desenvolvimento dessa área é a consolidação de uma linha de pesquisa voltada exclusivamente para os EIM na FMRP-USP.

Inborn errors of metabolism (IEM) are genetic diseases, mostly due to enzyme deficiencies leading to severe metabolic damages, increasingly diagnosed. The aim is to describe the history of the development of IEM diagnosis and treatment in the Hospital of Clinics of Ribeirão Preto, São Paulo University (HCFMRP-USP). At the beginnings of the Post-Graduate Programs in the School of Medicine of Ribeirão Preto of São Paulo University (FMRP-USP), the first thesis on IEM was performed in 1980 on cystinuria in the area of Genetics; G6PD goal was the second in 1987 in Pediatrics. Since that time, IEM diagnosis was possible, in the sequence, due to the chromatography of amino acids routine by the Center for Protein Chemistry, FMRP-USP in 1984, the partnership with the Department of Genetics, Hospital of Clinics of Porto Alegre. RS in 1988 and the urine screening in the Nutrology Laboratory of FMRP-USP, that resulted of a Master in Neurology in 1990. In the last two decades: the specialized out patients clinics, the Program for Neonatal Screening, treatment by enzyme replacement and support of the Stem Cell Transplantation Center were implemented. It is noteworthy that by 2009, just one more thesis was presented.The perspective for the development of this area is the consolidation of a line of research focused exclusively on the EIM in FMRP-USP.

Errores innatos del metabolismo: una aproximación diagnóstica / Inborn errors of metabolism: a diagnostic approach

Los errores innatos del metabolismo (EIM), son enfermedades hereditarias, que obedecen generalmente a alteraciones enzimáticas. Al considerarlas en particular son raras, pero en conjunto representan una importante causa de morbi-mortalidad en la edad pediátrica. El diagnóstico es complicado, ya que las presentaciones clínicas son variadas y poco especificas, y además requieren de investigaciones de laboratorio especializadas. Se clasifican en tres grandes grupos, de acuerdo a los mecanismos fisiopatológicos implicados: los trastornos del metabolismo intermediario, los que obedecen al déficit en la producción de energía y por depósitos de macromoléculas. El conocimiento de los EIM por parte del clínico es fundamental, esto permitirá identificar los datos orientadores de la historia médica y del laboratorio, y solicitar las investigaciones requeridas para un diagnóstico temprano y un tratamiento oportuno.

The inborn errors of metabolism are hereditary diseases caused in most of the cases by enzimatic disturbs. These diseases are rare, but all of them are a very much important cause of morbi – mortality in children. The diagnoses is complicated because clinical presentations are so many and some specific and besides require specialized laboratory investigations. These diseases are classified in three groups, in order to the pshysiopathological mechanisms implicated: intermediary metabolism trastorns, energy production deficit and macromolecules depots. The clinician knowledgement about these diseases is crucial, because it will allow to identify clinical and laboratory dates and apply for required investigations in order to an early diagnosis and opportune treatment.

Homocystinuria due to cystathionine beta synthase deficiency.

A two year-old male child presented with cutis marmorata congenita universalis, brittle hair, mild mental retardation, and finger spasms. Biochemical findings include increased levels of homocysteine in the blood-106.62 micromol/L (normal levels: 5.90-16 micromol/L). Biochemical tests such as the silver nitroprusside and nitroprusside tests were positive suggesting homocystinuria. The patient was treated with oral pyridoxine therapy for three months. The child responded well to this therapy and the muscle spasms as well as skin manifestations such as cutis marmorata subsided. The treatment is being continued; the case is reported here because of its rarity. Homocysteinuria arising due to cystathionine beta-synthase (CBS) deficiency is an autosomal recessive disorder of methionine metabolism that produces increased levels of urinary homocysteine and methionine It manifests itself in vascular, central nervous system, cutaneous, and connective tissue disturbances and phenotypically resembles Marfan's syndrome. Skin manifestations include malar flush, thin hair, and cutis reticulata / marmorata.

A Case Report of Familial Benign Hypocalciuric Hypercalcemia: A Mutation in the Calcium-Sensing Receptor Gene

Familial benign hypocalciuric hypercalcemia (FBHH) is an autosomal dominant trait with high penetrance, clinically manifestating a relatively benign, lifelong, persistent hypercalcemia and hypocalciuria without hypercalcemic related complications. The calcium-sensing receptor (CaSR) plays an important role in the regulation of PTH secretion and calcium metabolism. Here we present a family with FBHH of an autosomal dominant inheritance. A heterozygous mutation of E297K (GAG -> AAG, exon 4) of CaSR gene was found in 3 family members. To our knowledge, it is the first confirmed case of FBHH with CaSR gene mutation in Korea.

Complex glycerol kinase deficiency: an X-linked disorder associated with adrenal hypoplasia congenita.

Complex glycerol kinase deficiency (GKD) results from the contiguous deletion on Xp21 of all or part of the gene for glycerol kinase together with that for adrenal hypoplasia congenita (AHC) and /or Duchenne muscular dystrophy (DMD). The authors present the case of a newborn whose initial issues were refractory hypoglycaemia along with hyponatremia and hyperkalemia. He also had low serum cortisol levels and raised urinary excretion of glycerol and required steroid supplementation. His creatinine phosphokinase (CPK) levels were normal. Molecular studies revealed a contiguous Xp21 deletion. Therapy in such cases must be prompt and includes correction of hypoglycaemia and dyselectrolytemia, a low fat diet and steroid replacement.

Problemas sociales en el diagnóstico y tratamiento de las enfermedades moleculares / Social problems in the diagnosis and treatment of the molecular illnesses

Se realizó una revisión bibliográfica acerca de determinados problemas éticos que generan los adelantos científicos en la Biología Celular y la Genética Molecular con la intención de identificarlos y divulgarlos para su posterior solución. La incorporación del método problémico en la enseñanza de la Bioquímica nos compromete a abordar los aspectos éticos en el aprendizaje de la misma, asignatura donde se estudian las enfermedades moleculares. Los problemas éticos se presentan en las diferentes etapas del diagnóstico, en el pesquisaje de portadores sanos y en el tratamiento de las enfermedades moleculares de los pacientes que logren sobrevivir con graves limitaciones para la incorporación a la sociedad como miembro socialmente útil. La violación del consentimiento informado y de la autonomía, en el diagnóstico perinatal y prenatal, así como en la determinación de parejas heterocigóticas son de manera general los más comunes de los problemas. Existen además dilemas éticos en el tratamiento y los creados por disposiciones jurídicas contradictorias al abordar el estatus social especial del feto. Sería útil el conocimiento y la concienciación de estas limitaciones en un país donde está garantizada la accesibilidad gratuita de los servicios de genética a todos sus ciudadanos por igual.

Deficiência da 3-0H-3-metil-glutaril-Coa-Liase como causa de coma no período neonatal: relato de caso / 3-hydroxy-3-methyglutaryl-CoA-lyse deficiency as coma etiology in the neonatal period: case report

Estudamos um paciente que apresentou dois episódios de coma no primeiro mês de vida, com descompensaçao metabólica, nos quais se observou hipoglicemia e acidose metabólica acentuada, sem cetonúria. O estudo dos ácidos orgânicos urinários demonstrou elevaçao acentuada de 3-OH-3-metil-glutárico, 3-metil-glutacônico, 3-metil-glutárico e 3-OH-isovalérico. Os sinais e sintomas clínicos associados às alteraçoes metabólicas citadas permitiram o diagnóstico da deficiência da 3-OH-3-metil-glutaril-CoA-liase, entidade de origem autossômica recessiva, passível de ser tratada, como no caso estudado, com dieta hipoproteica, restrita em leucina, hipogordurosa e rica em carboidratos, associada a L-carnitina e evitando-se períodos prolongados de jejum.

Detección de aciduria metilmalónica mediante pruebas de tamizaje metabólico / Detection of methylmalonic aciduria by means of metabolic screening

La búsqueda de aciduria metilmalónica es uno de los procedimientos en el Programa de Detección de Errores Congénitos del Metabolismo que se realiza en varias unidades del IMSS en Monterrey, Nuevo León, para estudiar muestras procedentes de personas con sospecha de enfermedad metabólica genética. De un total de 2100 exámenes realizados en pacientes pediátricos, cinco resultaron positivos mediante la prueba del color y en todos ellos se corroboró la presencia del ácido metilmalónico mediante cromatografía A1 de celusosa. Aunque no se obtuvo diagnóstico de precisión, es probable que más de una forma del padecimiento exista en nuestro medio. Debido a la gravedad de este defecto, a la posibilidad del manejo médico y la conveniencia del asesoramiento genético en las familias portadoras, se justifica este tipo de detección en las unidades pediátricas o de atención materno-infantil.

Tamiz neonatal en América Latina: problemas y propuestas derivadas de la práctica clínica / Neonatal screening in Latin America: problems and proposals derived from clinical practice

Las pruebas de tamiz neonatal sirven para detectar a recién nacidos portadores de alguna patología endocrina, infecciosa o errores del metabolismo, antes de que la enfermedad se manifieste y previene, de ser posible, alguna discapacidad física, mental o la muerte. Se considera conveniente establecer un programa nacional de tamiz neonatal e infantil en México y en Latinoamérica, para hipotiroidismo congénito y evaluar la posibilidad de incluir a la hiperplasia adrenal congénita la toxoplasmosis congénita y el neuroblastoma mediante estudios piloto, que consideren un estricto control de calidad, sistemático y automatizado. El costo/beneficio del tamiz neonatal es positivo a la sociedad y evita el daño cerebral permanente, y/o la muerte de los niños