Factor VIII facts for kids

Factor VIII (FVIII) is a special blood clotting factor. It helps your blood form a clot when you get a cut or injury. Think of it like a tiny helper that stops you from bleeding too much! It's also called anti-hemophilic factor (AHF).

In humans, the instructions for making Factor VIII are found in a gene called F8. This gene is located on the X chromosome. If there's a problem with this gene, your body can't make enough working Factor VIII. This leads to a condition called hemophilia A, where blood doesn't clot properly. Hemophilia A is a recessive disorder, which means you usually need two copies of the faulty gene (or one copy if it's on the X chromosome, like in boys) to have the condition.

What is Factor VIII?

Factor VIII is a protein that plays a very important role in your body's ability to stop bleeding. When you get a cut, a series of steps happen in your blood to form a clot. This process is called the "coagulation cascade." Factor VIII acts like a key helper in one of these steps. It works with another factor, Factor IX, to activate Factor X, which then helps create the final clot. Without enough working Factor VIII, this chain reaction can't happen properly, and bleeding can continue for a long time.

Factor VIII and Hemophilia A

Hemophilia A is a genetic condition, meaning it's passed down through families. It happens when the F8 gene has a mistake, or "mutation." Because the F8 gene is on the X chromosome, hemophilia A mostly affects boys. Girls have two X chromosomes, so if one has a faulty F8 gene, the other X chromosome can often make enough Factor VIII. Boys only have one X chromosome, so if it has the faulty gene, they will have hemophilia A.

People with hemophilia A can have bleeding problems. This can include:

• Bleeding for a long time after a cut or injury.
• Easy bruising.
• Bleeding into joints or muscles, which can cause pain and damage.

Doctors can treat hemophilia A by giving patients Factor VIII. This can be Factor VIII made in a lab (called recombinant Factor VIII) or Factor VIII taken from donated human blood. This treatment helps their blood clot normally and prevents serious bleeding.

Images for kids

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  In human, the F8 gene is located on the X chromosome at position q28.

See also

In Spanish: Factor VIII (coagulación) para niños