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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.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.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

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.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.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.

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.To describe the clinicopathological and the genetic findings of eleven cases from a Spanish gypsy family with LGMD2C and the mutation C283Y.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.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.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.

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.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.

Introduccion. El deficit de mioadenilato desaminasa (MAD) constituye el defecto enzimatico geneticamente determinado mas frecuente del musculo esqueletico (2% de la poblacion); sin embargo, produce manifestaciones clinicas en forma de calambres y dolores musculares asociados al ejercicio en un numero bastante menor de personas, y es excepcional en los ninos. Caso clinico. Se trata de un varon de 7 anos, que consulta por intensas mialgias con la actividad fisica; se acompana de elevacion de creatincinasa a 3.273 UI/L (normal: 24-195), que desciende en periodos 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 enzimatica de la MAD, y se confirma mediante estudio genetico la mutacion nonsense Q12X, que presenta en homocigosis. Conclusion. Se debe descartar un deficit de MAD en todo paciente que presente mialgias asociadas al ejercicio fisico con elevacion de las enzimas musculares, que descienden al quedar asintomatico. El test de ejercicio del antebrazo en isquemia orienta sobre el tipo de trastorno metabolico muscular, aunque el diagnostico definitivo lo obtendremos mediante el estudio histoenzimatico de la biopsia muscular y el estudio genetico. A pesar de diagnosticarse raramente en ninos, el deficit de MAD debe incluirse en el diagnostico diferencial de los sindromes que cursan con intolerancia al ejercicio

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.