Genetic Study on Duchenne Muscular Dystrophy

Abstract

Duchenne muscular dystrophy (DMD) is a fatal hereditary disease resulting from a sex-linked gene. However, its position on genetic map and any products derived from the gene have never been known. We investigated siblings and parents of the probands with DMD for Xg blood group, color-blindness and DMD in forty-nine pedigrees in the south Kyushu district. The following genetic analyses were carried out. Since the observed rate of segregation on DMD was rather lower than the expected one, incomplete penetrance of DMD was considered in all analyses. Any significant linkage could not be detected between the loci for DMD and Xg blood group. The test of linkage between the loci for DMD and color-blindness could not be carried out because of very low frequency of color-blindness in the pedigrees. Mutation rate of DMD was estimated as 1.935×10^<-4> to 2.224×10^<-4> (/locus/generation), which was a little overestimated. The mutation rate of DMD may be presumably much higher than those of other X-linked diseases. More effort is required to clarify the reason for the high mutation rate and to discover the genetic cause of this disease.