Joey, age 9, is admitted to a pediatric unit with Duchenne muscular dystrophy. He inherited this condition through a:
A) sex-linked dominant trait.
B) sex-influenced trait.
C) sex-limited trait.
D) sex-linked recessive trait.

Question

Quizplus · Accepted Answer

Duchenne muscular dystrophy is caused by a recessive mutation on the X chromosome. Since males only have one X chromosome, they are more likely to be affected by the condition than females, who have two X chromosomes and can potentially inherit a normal copy to compensate for the mutated copy. Therefore, the inheritance pattern of Duchenne muscular dystrophy is sex-linked recessive.

Joey, Age 9, Is Admitted to a Pediatric Unit with Duchenne