Pronounced: He-moe-feel-ee-uhEn Español (Spanish Version)
Hemophilia is a group of bleeding disorders. It is caused by low amounts of specific clotting factors. These factors help to stop bleeding.
The most common types of hemophilia are:
- Hemophilia A (classic hemophilia)—accounts for 80% of all hemophilia (1 in 5,000 males), caused by too little factor VIII
- Hemophilia B (Christmas disease)—occurs in 1 in 20,000 males, caused by too little factor IX
Hemophilia is caused by a faulty gene located on the X chromosome.
Females carry two copies of the X chromosome. If the faulty gene is only on one X, the normal gene on the second X will take over. As a result, they will not get the disease. Instead, they are carriers of the gene. The risk for their male offspring to inherit the gene is 1 in 2 or 50%. The chance that their female offspring will inherit the gene is also 50%. These female offspring will be carriers like their mothers.
It is possible for a female to have hemophilia. For this to happen she must inherit the faulty gene from both her mother and her father.
Males carry only one X chromosome. If they get the faulty gene, the disease will develop.
It is possible for a new genetic mutation to occur. This means a person can get hemophilia even if neither parent carries a genetic mutation.
Genetic Outcome Possibilities
Copyright © Nucleus Medical Media, Inc.
Last reviewedJune 2013by Igor Puzanov, MD; Brian Randall, MD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.