Hemophilia is a rare inherited bleeding disorder wherein physiological blood clotting is impaired or does not occur due to inadequate clotting proteins or coagulation factors. This can lead to spontaneous bleeding or incessant bleeding from injury.
Hemophilia is inherited in an X-linked recessive pattern. Coagulation factors are reduced, impaired, or missing in hemophilia which leads to the symptoms experienced by those affected. The significant loss of factors are due to DNA mutations that prevent the synthesis of the proteins responsible for coagulating blood during injury.
There are three major types of Hemophilia that differ depending on the clotting factor affected. In Hemophilia A or Classic Hemophilia, variants in the F8 gene lead to reduced coagulation factor VIII. Mutations in the F9 gene lead to Hemophilia B, or Christmas disease, which is characterized by factor IX deficiency. In Hemophilia C, the lack of clotting factor XI occurs due to mutations in the F11 gene.
Rarely, hemophilia can also be acquired rather than inherited when the person’s own immune system attacks the body’s clotting factors. This can be associated with autoimmune diseases, pregnancy, multiple sclerosis, and cancer.
The severity of the signs and symptoms of hemophilia correlate to the degree of clotting factor insufficiency. With mild hemophilia, signs and symptoms manifest only after significant trauma or surgery which leads to continuous bleeding. Spontaneous bleeding is uncommon with mild hemophilia. With moderate to severe hemophilia, prolonged bleeding occurs after trauma, injury, dental work and surgery, and spontaneous bleeding may appear. Internal bleeding which may affect multiple organs, such as the brain, may also happen in severe hemophilia.
The signs and symptoms of hemophilia include:
Familial history and clinical manifestation play a role in diagnosing hemophilia. Screening tests and blood tests are done to determine coagulation factor deficiency and severity. Severe hemophilia manifests within the first year of life while milder forms of hemophilia may not be diagnosed until adulthood or after a surgical procedure.
Replacement therapy is the main treatment for hemophilia and it involves replacing the deficient clotting factor to allow blood to clot accordingly. Administration through a vein can be done through blood transfusions or from commercially available factor concentrates and should be done on a regular basis (prophylaxis) to prevent bleeding episodes.
Other treatments and therapies include:
There is no known way to prevent hemophilia as it is mostly a genetic condition. Instead, control of the disease is focused on avoiding profuse bleeding and protecting the joints. These include:
Mehta P, Reddivari AKR. Hemophilia. [Updated 2021 Dec 31]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK551607/
MedlinePlus [Internet]. Bethesda (MD): National Library of Medicine (US); [updated 2020 Jun 24]. Hemophilia; [updated 2022 May 6; cited 2022 Jul 19]. Available from: https://medlineplus.gov/genetics/condition/hemophilia/.
Centers for Disease Control and Prevention. Hemophilia. https://www.cdc.gov/ncbddd/hemophilia/facts.html. Accessed July 21, 2022
Hemophilia. Mayo Clinic Staff. https://www.mayoclinic.org/diseases-conditions/hemophilia/symptoms-causes/syc-20373327. Published October 7, 2021