Study of Muscle Biopsy in Children with Muscular Dystrophy

Muscular Dystrophy (MD) is a genetically heterogeneous group of disorders characterized by progressive weakness and degeneration of skeletal muscles. The present study was designed to help in proper diagnosis of different types of muscular dystrophy through analysis of muscle biopsy and not by clinical picture alone. In addition to Hematoxylin and eosin stain we used antidystrophin antibody to stain the muscle specimens. The study included 18 children diagnosed as having muscular dystrophy on clinical basis. They were selected from out-patient and Genetics specialized clinics, Pediatric Hospital, Ain Shams University. Their ages ranged from 9 to 180 months (mean value 90.3±54.5 months). They were 13 males (72.3%) and 5 females (27.7%). The primary diagnosis was based on clinical data and neurological examination then on creatine phosphokinase (CPK) values, electromyography (EMG) and nerve conduction (NCV) studies. The muscle biopsy was the final procedure to establish the diagnosis of muscular dystrophy and to know the type. All muscle biopsy specimens showed dystrophic pattern but with different degrees. We have also seen three different patterns of dystrophin expression using the anti-dystrophin antibody. Dystrophin stain was negative in (44.4%), positive in (38.8%) and mosaic in (16.8%). There was significant statistical relation between the duration of illness, presence of pseudohypertrophy and Gower s sign on one side and the result of dystrophin stain (being negative) (P= 0.033, 0.05 and 0.05 respectively). Also the presence of endomesial and perimesial fibrous tissues, which are important dystrophic changes, was significantly related to the result of dystrophin stain (being negative) (P= 0.028). This study proved that immunohistochemical analysis using antidystrophin antibody is important to differentiate between X-linked dystrophinopathy or its carrier state and severe childhood autosomal recessive muscular dystrophy (SCARMD).