What is the inheritance of hemophilia?
The gene that causes the lack or deficiency in the production of clotting factor shows a sex-linked pattern of heredity. The gene that controls the production of clotting factor is located on the female (X) chromosome. Females have two X chromosomes; males have an X and a Y. Males who inherit the defective gene on their X chromosome will have the disorder. Females who inherit the defective gene on one X chromosome and have a normal gene on the other X chromosome will be a carrier of hemophilia. Figure 1 shows the heredity pattern of hemophilia. Each son born to a carrier mother has a 50 percent chance of having the disorder and each daughter has a 50 percent chance of being a carrier. A male with hemophilia cannot pass the disorder to his sons, but all of his daughters will be obligate carriers.
