Population data on benign and severe forms of X-linked muscular dystrophy

Summary Epidemiological data on Becker muscular dystrophy (BMD) and Duchenne muscular dystrophy (DMD) from a large sample of the Italian population are reported. For BMD the incidence rate was found to be 5.5x10^-5 liveborn males (lbm) and the prevalence rate, 13.1x10^-6; the mutation rate was estimated to be about 6.0x10^-6. For DMD the incidence and prevalence rates were found to be respectively 26x10^-5 lbm and 31.6x10^-6. The DMD mutation rate obtained by the Haldane formula was 86.6x10^-6 and by the semi-direct method, 65.6x10^-6. The results are discussed in the light of possible allelism of BMD and DMD.