Question

Duchenne muscular dystrophy is a serious condition caused by a recessive allele of a gene on the human x chromosome. the patients have muscles that weaken over time because they have absent or decreased dystrophin, a muscle protein. they rarely live past their twenties. how likely is it for a woman to have this condition?

Answer 1

Duchenne muyscular dystrophy is caused by a mutation on the X chromosome, so a male gets it from his mother's X, if she is a carrier. The male child gets a Y and no X from his father, so the disease is always transmitted through the X from the mother. If a female gets Duchenne muscular dystrophy she has to have two X chromosomes, one from a carrier mother and another from from an affected father. This is virtually impossible because most males die before childbearing age and there is no way a female child can get an X from a man who does not live long enough to procreate. About eight percent of carrier women do show some muscle weakness, but they do not have the disease.