Hemophilia how is it passed on

The responsible gene is located on the X chromosome, and since males inherit only one copy of the X chromosome, if that chromosome carries the mutated gene then they will have the disease. Females have a second, usually normal, copy of the gene on their other X chromosome, so they capable of passing on the disease without experiencing its symptoms.

Hemophilia is an inherited disease that's characterized by bleeding beyond what would be expected in a normal individual. In other words, they have a deficiency in the ability to clot their blood.

Often, we think of hemophilia [as] associated with males. In other words, there are many more males that have hemophilia than females. This is true if the mother does not have a hemophilia allele herself. That would be very rare, unless the parents are related. Skip directly to site content Skip directly to page options Skip directly to A-Z link.

Section Navigation. Facebook Twitter LinkedIn Syndicate. How Hemophilia is Inherited. Minus Related Pages. Information For…. Links with this icon indicate that you are leaving the CDC website. In females who have two X chromosomes , a mutation would have to occur in both copies of the gene to cause the disorder. Because it is unlikely that females will have two altered copies of this gene, it is very rare for females to have hemophilia.

A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons. In X-linked recessive inheritance, a female with one altered copy of the gene in each cell is called a carrier. Carrier females have about half the usual amount of coagulation factor VIII or coagulation factor IX, which is generally enough for normal blood clotting.

However, about 10 percent of carrier females have less than half the normal amount of one of these coagulation factors; these individuals are at risk for abnormal bleeding, particularly after an injury, surgery, or tooth extraction. Genetics Home Reference has merged with MedlinePlus. Learn more. The information on this site should not be used as a substitute for professional medical care or advice. Contact a health care provider if you have questions about your health.

From Genetics Home Reference. Description Hemophilia is a bleeding disorder that slows the blood clotting process. Frequency The two major forms of hemophilia occur much more commonly in males than in females. Causes Changes in the F8 gene are responsible for hemophilia A, while mutations in the F9 gene cause hemophilia B. Learn more about the genes associated with Hemophilia F8 F9. Inheritance Hemophilia A and hemophilia B are inherited in an X-linked recessive pattern.

Research Studies from ClinicalTrials. Haemophilias A and B. Citation on PubMed Franchini M. Acquired hemophilia A.