Duchenne muscular dystrophy (DMD) is normally an X-linked recessive human disease affecting boys. Girls afflicted with DMD are rare. Cytogenetic studies of several girls with DMD have in each case revealed that these individuals carry X-autosome translocations. The autosomes vary, but the breakpoint on the X in every case is in band p21, which is the location of the DMD gene. Cytogenetic studies further revealed that in all cells studied in such DMD girls the normal X chromosome exists as a Barr body. How might these observations account for the existence of DMD-affected girls? Why is only the normal X, but not the translocated X, inactivated?

Question

Quizplus · Accepted Answer

The Answer of Duchenne muscular dystrophy (DMD) is normally an X-linked recessive human disease affecting boys. Girls afflicted with DMD are rare. Cytogenetic studies of several girls with DMD have in each case revealed that these individuals carry X-autosome translocations. The autosomes vary, but the breakpoint on the X in every case is in band p21, which is the location of the DMD gene. Cytogenetic studies further revealed that in all cells studied in such DMD girls the normal X chromosome exists as a Barr body. How might these observations account for the existence of DMD-affected girls? Why is only the normal X, but not the translocated X, inactivated?

Duchenne Muscular Dystrophy (DMD) Is Normally an X-Linked Recessive Human