Hemophilia why more common in males

X-linked inheritance means that the gene causing the trait or the disorder is located on the X chromosome. Females have two X chromosomes. Males have one X chromosome and one Y chromosome. Genes on the X chromosome can be recessive or dominant. Their effect in males and females is not the same. For males, there needs to be only one copy of a nonworking gene on their 1 copy of the X chromosome for the trait or disorder to appear.

Females are generally not affected unless both copies of the gene one on each X chromosome are not working. Females who carry only 1 copy of an affected gene may not have any symptoms of the condition or may show mild symptoms compared with males.

There is a 1 in 2 chance that daughters carry the gene and can pass it to the next generation. There is a 1 in 2 chance that a daughter will not carry the gene and so cannot pass it on. There is a 1 in 2 chance that sons don't have the gene and will be healthy.

The earlier sections in this website that relate to understanding hemophilia, its causes , symptoms , diagnosis , treatment , and complications , all apply to women with hemophilia as well. As a woman with hemophilia, of any severity, reach out and schedule an appointment to speak with providers at IHTC about any aspect of your care.

We are here for you. Humans are born with 46 chromosomes, half from their mother and half from their father. X-linked disorders are associated with mutations on the X-chromosome. If you are a woman and your father had hemophilia, you are always a carrier. The IHTC comprehensive care team has genetic counselors, psychologists, social workers, and a number of other professionals who will guide and support you in every stage of taking care of yourself as a carrier, as well as planning for a family through evaluating reproductive options, genetic testing, emotional support, and education.

These genes are located on the X chromosome. Males inherit the X chromosome from their mothers and the Y chromosome from their fathers. Females inherit one X chromosome from each parent. The X chromosome contains many genes that are not present on the Y chromosome. This means that males only have one copy of most of the genes on the X chromosome, whereas females have 2 copies. Thus, males can have a disease like hemophilia if they inherit an affected X chromosome that has a mutation in either the factor VIII or factor IX gene.

Females can also have hemophilia, but this is much rarer. In such cases both X chromosomes are affected or one is affected and the other is missing or inactive. In these females, bleeding symptoms may be similar to males with hemophilia. Sometimes a female who is a carrier can have symptoms of hemophilia.

In addition, she can pass the affected X chromosome with the clotting factor gene mutation on to her children. Learn more about the inheritance pattern for hemophilia.

Even though hemophilia runs in families, some families have no prior history of family members with hemophilia. Sometimes, there are carrier females in the family, but no affected boys, just by chance. However, about one-third of the time, the baby with hemophilia is the first one in the family to be affected with a mutation in the gene for the clotting factor. Hemophilia occurs in about 1 of every 5, male births. Based on recent study that used data collected on patients receiving care in federally funded hemophilia treatment centers during the period , about 20, as many as 33, males in the United States are living with the disorder.

Hemophilia A is about four times as common as hemophilia B, and about half of those affected have the severe form. Hemophilia affects people from all racial and ethnic groups.