Hemophilia A is a genetic disorder that affects how well your blood clots. With treatment and proactive management, many people with hemophilia A can lead typical, active lives.

Hemophilia is a broad term that describes a group of genetic bleeding disorders caused by a deficiency in certain clotting factors. The type of hemophilia you have depends on the location of the genetic alteration and which clotting factors are affected.

Clotting factors are proteins in your blood. They work together to create clots, an essential part of your healing process that prevents blood loss and sets the foundation for tissue repair.

If your doctor diagnoses you with hemophilia A, learning as much as you can about your condition can help support the success of your long-term management.

Hemophilia A and hemophilia B make up the two primary types of hemophilia. These are genetic conditions that create a deficiency in clotting factors and reduce how well your blood forms clots.

Hemophilia A is due to a genetic alteration to the gene F8 on your X chromosome. When this gene is affected, your body doesn’t produce enough clotting factor VIII.

Without enough clotting factor VIII, the clotting process is negatively affected. It can take much longer for your body to form a clot, clots may not form at all, and the clots that do form may not be stable.

The severity of hemophilia A can vary among people. The specific alteration to your F8 gene influences how much clotting factor VIII your body can produce.

In severe hemophilia A, clotting factor VIII is less than 1% or undetectable. Spontaneous bleeding can happen regularly, multiple times a month, from everyday living or unknown causes.

Spontaneous bleeding episodes are internal and can become very painful as blood creates pressure and inflammation in different areas of the body. Your joints, muscles, and mucous membranes are common places for spontaneous bleeding.

In moderate hemophilia A, your body makes slightly more clotting factor VIII. You will still likely experience prolonged bleeding from mild injuries and may have spontaneous bleeding on a monthly or yearly basis.

Mild hemophilia A clotting factor VIII levels range between 5% and 40%. Spontaneous bleeding episodes are rare with this severity of hemophilia A. However, you’re still likely to have prolonged or excessive bleeding after mild tissue trauma.

How long someone with hemophilia A lives depends on factors like the severity of their condition, age, overall health, and if they’re actively receiving treatment.

While survival rates are improving with treatment, the life expectancy of someone with either hemophilia A or B is still lower than the general population.

A cross-sectional study from 2019 indicates the average life span of a person living with severe hemophilia A has improved to around 56.8 years.

A 2023 cohort study found among males with hemophilia A or B, the median age at end of life was 65.5 years, though racial disparities between non-Hispanic Black males (56 years) and non-Hispanic white males (68 years) were significant.

Hemophilia A is a genetic condition and is not transmissible. As a hereditary condition, however, it can be passed from parents to their children.

Living with hemophilia A means you have to be careful about bleeding. You’ll need to be mindful of the activities you choose to take part in, and you may need to take extra safety precautions before, during, and after participating.

If you play baseball, for example, helmets, face masks, eye protection, and the use of special bases called “breakaway” bases can help prevent injury. You may need to play a specific position to spare your joints.

The severity of hemophilia A and the success of treatment will determine its role in your daily life. If you’ve received a diagnosis of severe hemophilia A, without treatment, even everyday physical activities can cause spontaneous bleeding in any organ system in your body.

Your doctor will work with you to create an individualized lifestyle guide for managing hemophilia A.

Hemophilia A primarily affects males because it comes from a genetic alteration on the X chromosome. Boys have one X chromosome from their female parent and one Y chromosome from their male parent.

The presence of the Y chromosome dictates male sex. Female sex is determined when a male parent passes on an X chromosome instead of a Y. In other words, males have the XY pairing, and females have the XX pairing.

Because males only have one X chromosome, genetic alterations on that chromosome can affect them more severely. Females have two X chromosomes, so an alteration on one can be offset by the unaltered gene on its pair.

Hemophilia A is classified as an X-linked recessive trait because it will not always develop from a single copy of the altered F8 gene. It requires the presence of two genetically altered X chromosomes in females or a single altered X chromosome in males.

For a trait to be “dominant,” it will always appear even if only one chromosome is affected.

Hemophilia A’s effect on your clotting factor VIII levels is determined at birth. It won’t change over time.

Hemophilia A symptoms may seem worse with age. However, the changes may be related to natural changes and co-occurring medical conditions that affect the integrity and health of your body’s tissues.

The more fragile your blood vessels become from age, for example, the more likely you may be to experience problematic bleeding.

Hemophilia A and von Willebrand disease are not the same. Both conditions affect blood clotting but involve different parts of the clotting cascade.

Hemophilia A is a deficiency in clotting factor VIII. Von Willebrand disease is a deficiency in von Willebrand factor — a glycoprotein that serves as a carrier for clotting factor VIII. It occurs from a genetic alteration of the von Willebrand gene, vWF.

Hemophilia A is always congenital, meaning it is present at birth. In approximately 30% of cases, it is not hereditary but is due to a genetic alteration that occurs during embryonic development.

The outlook in hemophilia A is considered guarded. Even with treatment, there is a risk that bleeding — particularly in vulnerable locations like the head — could be life threatening.

Hemophilia A is a genetic condition that affects how well your blood clots. Caused by a genetic alteration in the F8 gene, it lowers the amount of clotting factor VIII produced by your body.

How hemophilia A affects your life can depend on its severity, but many people can lead active, typical lifestyles with proper treatment and proactive safety measures.