RESUMO
<p><b>OBJECTIVE</b>To identify potential mutations in patients featuring Becker muscular dystrophy (BMD) and to enhance the understanding of non-deletion/duplication mutations of the dystrophin gene causing BMD.</p><p><b>METHODS</b>Clinical data of two patients affected with BMD were collected. Potential mutations in the dystrophin gene were screened with multiplex ligation-dependent probe amplification assay (MLPA). Biopsied muscle samples were examined with HE staining, immnostaining with anti-dystrophin antibody, and electronic microscopy.</p><p><b>RESULTS</b>MLPA assay suggested that both cases were probably due to non-deletion/duplication mutations of the dystrophin gene. Light and electronic microcopy of skeletal muscle biopsies confirmed dystrophic changes in both patients. For patient A, immunostaining showed non-contiguous weak staining for most parts of sarcolemma. For patient B, immunostaining showed positive result with N-terminal anti-dystrophin antibody and negative result with C-terminal anti-dystrophin antibody.</p><p><b>CONCLUSION</b>For patients with mild phenotypes but without dystrophin gene deletion/duplication, muscle biopsy and immunochemistry are helpful for diagnosis and prognosis.</p>