Foram estudados por análise estatística 194 parâmetros clínicos, laboratoriais, eletrofisiológicos, histoquímicos e imuno-histoquímicos de 112 casos de distrofia muscular de Duchenne (DMD) e de 26 casos de distrofia muscular de Becker (DMB). Houve diferença significante (p < 0,05) entre as duas doenças com respeito a época de início de diversos sintomas, dados do exame neurológico e alterações específicas na biópsia muscular. A biópsia muscular (BM) isolada foi diagnóstica em 52,7% dos casos de DMD e em 69,2% dos de DMB. Por imunofluorescência (60 casos) a distrofina estava ausente em 87% dos casos de DMD e apresentava falhas focais em todos os casos de DMB. A BM foi concordante com a imunofluorescência para distrofina em 82,6% dos casos de DMD e 71,4% dos de DMB. São feitos comentários a respeito dos dados encontrados e os da literatura, bem como sobre a dificuldade diagnóstica para diferenciação precoce das duas entidades.

194 clinical, laboratory, electrophysiologic, histological, histochemical and immunohistochemical parameters "were studied through statistical analysis in 112 cases of Duchenne muscular dystrophy (DMD) and in 26 cases of Becker muscular dystrophy (BMD). It was found a significant statistical difference. (p<0.05) between the two groups concerning the age of evaluation, beginning of symptoms, difficulty in walking, running, climbing and going downstairs, frequent falling down, support to walk, localized muscle pain, stopping climb stairs, and inability to walk. Muscle biopsy showed statistically significant (p<0.05) differences between the two groups regarding the intensity of connective tissue and focal adipose tissue proliferation, presence of diffuse rounded atrophic and angulated fibers, diffuse hypertrophic and splitting fibers. There were also differences regarding excessive internal fibers nuclei, hypertrophic types 1 and 2 fibers, angulated atrophic fibers and focal increasing in the NADH-TR, angulated atrophic fibers in non-specific esterase, and accumulated NBT in the periphery of fibers in succinic dehidrogenase. Isolatedly muscle biopsy gave the correct diagnosis in 52.7% of DMD cases and in 69.2%. of BMD cases. Dystrophin detection by immunofluorescence (60 cases) showed: absence in 87.0% of fibers in DMD cases, and sarcolemmial membrane discontinuités in all BMD¹ cases. The muscle biopsy diagnosis had an agreement with the dystrophin results in 82.6% of DMD¹ cases and 71.4% of BMD cases.