Further evidence for Xp21 location of Duchenne muscular dystrophy (DMD) locus: X;9 translocation in a female with DMD.

Females who fully manifest Duchenne muscular dystrophy (DMD), an X linked disorder, are extremely rare. Cytogenetic studies are indicated in such females to rule out an X chromosome abnormality, which could render a female hemizygous for X linked genes. At present there are six reports describing females with Duchenne muscular dystrophy and an X; autosome translocation. Although each of these six rearrangements involves a different autosome, (chromosomes 11, 21, 1, 3, 5, and 6) they have in common a breakpoint at Xp21. We report here our observations of a further female with DMD who carries a de novo translocation between Xp and 9p. The breakpoint in our patient is also located at Xp21, adding evidence for the assignment of this band as the site of the DMD gene.