Overview

Hemophilia is an inherited bleeding disorder in which a person lacks or has low levels of certain proteins called “clotting factors” and the blood doesn’t clot properly as a result. This leads to excessive bleeding.1 According to the World Federation of Hemophilia (WFH), about one in 10,000 people are born with this disease.2

Types

• Hemophilia A is the most common type of hemophilia, and it’s caused by a deficiency in factor VIII. According to the National Heart, Lung, and Blood Institute (NHLBI), eight out of 10 people with hemophilia have hemophilia A.3
• Hemophilia B, which is also called Christmas disease, is caused by a deficiency of factor IX.
• Hemophilia C is a mild form of the disease that’s caused by a deficiency of factor XI. People with this rare type of hemophilia often don’t experience spontaneous bleeding. Hemorrhaging typically occurs after trauma or surgery.1

Symptoms

The extent of your symptoms depends on the severity of your factor deficiency. People with a mild deficiency may bleed in the case of trauma. People with a severe deficiency may bleed for no reason. This is called “spontaneous bleeding.”1

Spontaneous bleeding can cause the following:

• blood in the urine
• blood in the stool
• deep bruises
• large, unexplained bruises
• excessive bleeding
• bleeding gums
• frequent nosebleeds
• pain in the joints
• tight joints
• irritability (in children)1

Causes and risk factors

Hemophilia is an inherited genetic condition, meaning it is passed down through families. It’s caused by a defect in the gene that determines how the body makes factors VIII, IX, or XI. These genes are located on the X chromosome, making hemophilia an X-linked recessive disease.1