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 seen as a Barr body?

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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 seen as a Barr body?

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