Duchenne Muscular Dystrophy

Duchenne muscular dystrophy (DMD,
McKusick 310200) is the most common of the
more than 10 clinically and genetically distinct
muscular dystrophies. It is caused bymutations
in the DMD gene. It occurs in 1 of 3500 live
born males either by a new mutation or by
transmission of the mutation from a heterozygous
mother or a mother with germline mosaicism
(i.e., the mother carries a DMD mutation in
a variable proportion of her germ cells). The
mutation rate is high, probably because the
gene is unusually large and has a high rate (10%)
of recombination within it. The French neurologist
Guillaume Duchenne (1806–1875) was the
first to report this disease, in 1861.
A clinically milder variant, Becker muscular
dystrophy (BMD), is an allelic disorder due to
in-framemutations in the same gene that allow
residual function of the dystrophin protein.