Glucose-6-phosphate dehydrogenase deficiency (G6PD) is inherited as an X-linked recessive allele in humans. A woman whose father suffered from G6PD marries a man who has the disease. What proportion of their sons would have the disease?
A) 100%
B) 1/2
C) 1/4
D) zero

Question

Quizplus · Accepted Answer

Since the woman is a carrier for the G6PD gene on one of her X chromosomes, she can pass either the normal allele or the disease allele to her offspring. The man, who has G6PD disease, can only pass the disease allele to his offspring. Thus, the sons of this couple have a 50% chance of inheriting the disease allele from their mother and a 100% chance of inheriting the disease allele from their father if they are male. Therefore, 1/2 or 50% of their sons would have the disease.

Glucose-6-Phosphate Dehydrogenase Deficiency (G6PD) Is Inherited as an X-Linked Recessive