Alerts and Notices
SynopsisHemophilia B, also known as Christmas disease, is a bleeding disorder due to factor IX deficiency. It is less common than hemophilia A and is also an X-linked autosomal recessive disorder that occurs most commonly in males.
Hemophilia B is characterized by prolonged bleeding following injuries, surgical procedures, and dental extractions. It can present with variable phenotypes. In a small percentage of female carriers, it may present in a milder form. Onset depends on severity of phenotype, but bleeding episodes may begin in early childhood and adolescence. More severe forms frequently present with spontaneous hemorrhage. Left untreated, hemophilia B may be fatal (intracranial hemorrhage) or result in severe motor impairment or paralysis (chronic joint disease).
Rarely, hemophilic pseudotumors may result from destruction of bone at sites of repeated bleeding. They may cause swelling and restricted movement.
Hemophilia B is a chronic condition with no known cure. A clinical trial has found that gene therapy using a viral vector with a high-specific-activity factor IX variant was significantly effective in treating hemophilia B, although gene therapy is not the standard of care or readily available, and treatment focuses primarily on adverse event prevention and prophylaxis.
Related topic: Hemophilia A
D67 – Hereditary factor IX deficiency
41788008 – Hereditary factor IX deficiency disease
Differential Diagnosis & Pitfalls
- Vitamin K deficiency – Factor 2, 7, and 10 will also be low.
- Glanzmann thrombasthenia
- Von Willebrand disease
- Hemophilia A – Clinically similar to hemophilia B; factor VIII deficiency.
- Coagulation factor deficiency (eg, 5, 7, 10, 11)
- Fibrinogen deficiency
- Scurvy – Bleeding is primarily mucosal, not musculoskeletal.
- Disseminated intravascular coagulation – Usually has decreased platelet count.
- Child abuse – Normal coagulation labs.
- Platelet dysfunction – Bleeding is primarily mucocutaneous, not musculoskeletal.
- Fabry disease – Bleeding is primarily mucosal.