While there are numerous types of hemophilia, the most common type is hemophilia A. Also referred to as factor VIII deficiency hemophilia, or simply “classic” hemophilia, hemophilia A is a blood disorder where the ability to form blood clots is either missing or severely limited.
As a result, persons with hemophilia A will generally bleed much longer than the average person with normal clotting factors. In some instances where significant or traumatic injuries, such as those that might be suffered in an auto accident, could become life-threatening.
In this article, we’ll take a look at some of the facts about hemophilia A.
What causes hemophilia A?
Hemophilia A is caused by a gene mutation that is located on the X chromosome. Because it’s caused by a gene mutation, in most instances hemophilia A is inherited. This means that people with hemophilia A inherited the mutated gene which causes this disorder, from one of their parents.
However, this is not always the case. In about 30 percent of all hemophilia A cases, there is no known family history of hemophilia A. It these cases, it appears that the gene causing hemophilia A mutates on its own without any apparent or known underlying cause.
Tell me more about the gene mutation. How does that work?
To understand how the gene mutation that causes hemophilia A works, you need to think back to your high school biology class. Everyone has two sex chromosomes -- either XX or XY.
Men have both an X and a Y chromosome. They inherit the X chromosome from their mother and the Y chromosome from their father. Women, on the other hand, receive an X chromosome from both parents. So, the sex chromosomes for men are referred to as XY and XX for women.
The gene mutation that causes hemophilia A is located on the X chromosome. As a result, if a man has hemophilia A, the mutated gene is passed to his daughters who become carriers. This is true for all daughters of men who have hemophilia. On the other hand, none of his sons will have hemophilia.
Women who are carriers of the hemophilia A gene need to be aware that they can pass the gene mutation on to their children.