Question

Some female carriers of hemophilia B (an X-linked recessive disease) have symptoms of the disease. Which of the following is the most likely explanation for how this occurs?

(A) The X chromosome for the normal gene is inactivated in a majority of cells in the body.
(B) Triplet repeat expansion.
(C) Incomplete penetrance.
(D) Variable expressivity.

Answer 1

Female carriers of hemophilia B may have symptoms of the disease due to the inactivation of the X chromosome for the normal gene in a majority of cells in the body.

Step-by-step explanation:

Female carriers of hemophilia B, an X-linked recessive disease, may have symptoms of the disease due to the inactivation of the X chromosome for the normal gene in a majority of cells in the body. This process is known as X chromosome inactivation. In some cells, the X chromosome with the normal gene is inactivated, leading to the expression of the disease in those cells. This explains why some female carriers of hemophilia B have symptoms of the disease.