[Myoadenylate deaminase deficiency in a child with myalgias induced by physical exercise]. / Déficit de mioadenilato desaminasa en un niño con mialgias relacionadas con la actividad física.

INTRODUCTION: Myoadenylate deaminase deficiency (MAD) constitutes the most common genetically determined enzymatic defect of the skeletal muscle (2% of the population), however, it causes clinical symptoms such us exercise-related muscle cramps and pain in quite a lower number of patients, being exceptional in children. CASE REPORT: A 7 year old boy is referred with intense myalgias after physical exertion associating increased creatin kinase level 3,273 UI/L (normal 24-195) which goes down in rest period to increase again with myalgias during exercise. The ischemic forearm exercise test shows a flat ammonia curve with a normal lactate rise in relation to control. In muscle biopsy, an absence of the enzymatic activity of myoadenylate deaminase is observed and the genetic analysis proves the 'nonsense' Q12X mutation which he has in a homozygous status. CONCLUSION: MAD deficiency must be ruled out in every patient with exertional myalgia and increased CK which normalizes when asymptomatic. The ischemic forearm exercise test guides about the muscle metabolic disorder type, although the definitive diagnosis is obtained through the muscle biopsy histoenzymatic analysis and genetic techniques. Although rarely diagnosed in children, MAD deficiency must be included in the differential diagnosis of syndromes with exercise intolerance

Déficit de mioadenilato desaminasa en un niño con mialgias relacionadas con la actividad física / Myoadenylate deaminase deficiency in a child with myalgias induced by physical exercise

Introducción. El déficit de mioadenilato desaminasa (MAD) constituye el defecto enzimático genéticamente determinado más frecuente del músculo esquelético (2 por ciento de la población); sin embargo, produce manifestaciones clínicas en forma de calambres y dolores musculares asociados al ejercicio en un número bastante menor de personas, y es excepcional en los niños. Caso clínico. Se trata de un varón de 7 años, que consulta por intensas mialgias con la actividad física; se acompaña de elevación de creatincinasa a 3.273 UI/L (normal: 24-195), que desciende en períodos de reposo, para ascender con nuevas mialgias con el ejercicio. En el test de ejercicio del antebrazo en isquemia se objetiva una curva plana del amonio, con ascenso normal del lactato respecto al control. En la biopsia muscular se observa la ausencia de actividad enzimática de la MAD, y se confirma mediante estudio genético la mutación nonsense Q12X, que presenta en homocigosis. Conclusión. Se debe descartar un déficit de MAD en todo paciente que presente mialgias asociadas al ejercicio físico con elevación de las enzimas musculares, que descienden al quedar asintomático. El test de ejercicio del antebrazo en isquemia orienta sobre el tipo de trastorno metabólico muscular, aunque el diagnóstico definitivo lo obtendremos mediante el estudio histoenzimático de la biopsia muscular y el estudio genético. A pesar de diagnosticarse raramente en niños, el déficit de MAD debe incluirse en el diagnóstico diferencial de los síndromes que cursan con intolerancia al ejercicio (AU)

Introduction. Myoadenylate deaminase deficiency (MAD) constitutes the most common genetically determined enzymatic defect of the skeletal muscle (2% of the population), however, it causes clinical symptoms such us exercise-related muscle cramps and pain in quite a lower number of patients, being exceptional in children. Case report. A 7 year old boy is referred with intense myalgias after physical exertion associating increased creatinkinase level 3,273 UI/L (normal 24-195) which goes down in rest period to increase again with myalgias during exercise. The ischemic forearm exercise test shows a flat ammonia curve with a normal lactate rise in relation to control. In muscle biopsy, an absence of the enzymatic activity of myoadenylate deaminase is observed and the genetic analysis proves the ‘nonsense’ Q12X mutation which he has in a homozygous status. Conclusion. MAD deficiency must be ruled out in every patient with exertional myalgia and increased CK which normalizes when asymptomatic. The ischemic forearm exercise test guides about the muscle metabolic disorder type, although the definitive diagnosis is obtained through the muscle biopsy histoenzymatic analysis and genetic techniques. Although rarely diagnosed in children, MAD deficiency must be included in the differential diagnosis of syndromes with exercise intolerance (AU)

Polineuropatía periférica, hipoacusia y neuropatía óptica de probable origen toxicocarencial / Peripheral polyneuropathy, hypoacusis and optical neuropahty with probable toxic and deficiency related origins

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Metodología diagnóstica en la patología muscular / Diagnostic methodology in muscular pathologies

Objetivo. Analizar las diversas metodologías y su enfoque técnico, y comparar la utilidad y la especificidad de cada una de ellas en la interpretación diagnóstica de la biopsia muscular. Desarrollo. Desde las primeras descripciones de Duchenne en el siglo XIX hasta la actualidad, se han superado una serie de etapas, cruciales en el abordaje metodológico, para la interpretación de la biopsia muscular. Los grandes grupos de enfermedades musculares (atrofia neurógena, distrofia y otros) que se establecieron sobre la base del estudio puramente morfológico, se examinaron posteriormente mediante técnicas histoquímicas que permitían individualizar algunas enfermedades. Un factor determinante en la interpretación de las biopsias musculares y en la exactitud diagnóstica fue la aplicación de técnicas inmunohistoquímicas. El descubrimiento del gen responsable de las distrofias musculares de Duchenne y Becker y, posteriormente, la identificación de la distrofina mediante genética inversa, desencadenaron una serie de acontecimientos que condujeron a la identificación de múltiples genes y proteínas, responsables de otras tantas enfermedades musculares. A partir de este momento, se pudo distinguir entre distrofias musculares antes no definidas -p. ej., diferentes tipos de distrofias de cintura-, subclasificar enfermedades alélicas -como la distrofia muscular de Becker- identificar portadoras de enfermedades ligadas al cromosoma X y otras posibilidades. También el examen ultraestructural ha demostrado ser de gran utilidad. Conclusión. En la actualidad, la precisión diagnóstica alcanzada en la patología muscular es notable, y los descubrimientos alcanzados gradualmente han marcado una serie de etapas, ninguna de las cuales ha excluido a la anterior, que tienen todas ellas gran importancia a la hora de interpretar una biopsia muscular (AU)

Aims. To analyse the different methodologies and their technical approaches, and compare the value and specificity of each of them in the diagnostic interpretation of muscular biopsies. Development. Since the first descriptions by Duchenne in the 19th century, a series of stages for interpreting muscular biopsies crucial to the methodological approach were developed. The largest groups of muscular diseases (neurogenic atrophy, dystrophy and others), which were established on the basis of purely morphological studies, were later examined using histochemical techniques that allowed some diseases to be considered on an individual basis. One decisive factor in interpreting muscular biopsies and in diagnostic accuracy was the application of immunohistochemical techniques. The discovery of the gene responsible for Duchenne and Becker muscular dystrophies, and the later identification of dystrophin using reverse genetics, triggered off a series of events which led to the identification of various genes and proteins responsible for a number of muscular diseases. From that moment onwards it became possible to distinguish between previously undefined muscular dystrophies, e.g. different types of limb girdle dystrophy, to subclassify allelic diseases, such as Becker muscular dystrophy, and to identify carriers of X-linked diseases, for example. Ultrastructural examinations have also proved to be very useful. Conclusion. At present, the degree of diagnostic accuracy achieved in muscular pathologies is remarkable and the discoveries that have gradually been made have marked a series of stages, none of which has excluded the one preceding it and all of which are of great importance when it comes to interpreting a muscular biopsy (AU)

[Gamma-sarcoglycanopathy: clinico-pathological and genetic study of 11 cases]. / Gamma-sarcoglicanopatía: estudio clinicopatológico y genético de 11 casos.

INTRODUCTION: Limb Girdle Muscular Dystrophy type 2C (LGMD2C) is an autosomal recessive dystrophy due to the deficit of gamma-sarcoglycan, one of the proteins of the dystrophin-associated proteins complex (DAP). A new mutation in the gamma-sarcoglycan gene, 13q12, has been described recently and is exclusive of the gypsy community. OBJECTIVE: To describe the clinicopathological and the genetic findings of eleven cases from a Spanish gypsy family with LGMD2C and the mutation C283Y. MATERIAL AND METHODS: We describe a large gypsy family with the C283Y mutation and eleven affected patients. We have performed an extensive clinical and pathological study with immunohistochemistry and Western blot analyses in the eleven patients and a genetic study of a total of twenty-seven members of the family. RESULTS: The patients presented a severe muscular dystrophy with a dystrophic pattern in the muscle biopsy, normal immunolabeling for dystrophin, very weak for alpha-, beta- and delta-sarcoglycan and absent for gamma-sarcoglycan. These eleven patients were found to be homozygous for the mutation and twelve other members of the family, heterozygous. CONCLUSIONS: The clinical picture and the evolution of the disease herein described is similar to that observed in DMD. Two fundamental differences were found: the autosomal recessive mode of inheritance, and the normal immunohistochemistry and immunoblot for dystrophin in the skeletal muscle.

[Dystrophinopathies, congenital muscular dystrophy, limb-girdle dystrophies: updated classification]. / Distrofinopatías, distrofia muscular congénita y distrofias de cinturas: clasificación actualizada.

OBJECTIVES: To review the up-dated classification of limb girdle muscular dystrophies (LGMDs) in relation to the defective protein and the genetic abnormality. To explain how these proteins are related to dystrophin and to the proteins of the extracellular matrix. To show that an accurate diagnosis is necessary and that it can be adequately made in neuromuscular pathology laboratories. DEVELOPMENT: We present a study of the different types of LGMDs, dystrophinopathies and congenital muscular dystrophy. We emphasize the recent events which concluded in the identification of these disorders, the genetic alteration, the defective proteins and, briefly, the clinical features. CONCLUSIONS: The recent identification of numerous skeletal muscle proteins and of the codifying genes made possible a new classification of a large group of muscular dystrophies. The possibility to study these proteins on the muscle biopsy with immunohistochemistry and Western blot techniques indicates the need of an accurate diagnosis in specialized neuromuscular laboratories. Since there is a great number of genes discovered and of mutations within the same gene, and the clinical picture of different diseases can be similar, a previous study of the protein is advisable as a guide for a further genetic study.

[The association of Marchiafava-Bignami disease, cerebral pellagra and cerebellar degeneration in an alcoholic patient]. / Asociación de enfermedad de Marchiafava-Bignami, pelagra cerebral y degeneración cerebelosa en un paciente alcohólico.

INTRODUCTION: Marchiafava-Bignami disease, cerebral pellagra and alcoholic cerebellar degeneration are a group of diseases included in the alcoholic encephalopathies, although they may also be caused by metabolic or nutritional disorders. The isolated appearance of these diseases usually permits diagnosis during the life of the patient, based on the neuro-radiological findings. However, their combination leads to complex form, with variable neurological expression, which means that precise diagnosis may often be post mortem. CLINICAL CASE: We present a malnourished alcoholic patient with neurological features compatible with alcoholic encephalopathy. The post mortem findings showed lesions typical of alcoholic cerebellar degeneration, cerebral pellagra and Marchiafava-Bignami disease.