Haemophilia

Key points

• Haemophilia is an X-linked recessive coagulation disorder (haemophilia A: factor VIII deficiency; haemophilia B: factor IX deficiency)
• Up to 30% of patients have no family history of the condition (new mutation)
• Features: haemarthroses, haematomas, prolonged bleeding after surgery or trauma
• Blood tests: prolonged APTT; bleeding time, thrombin time and prothrombin time are normal
• Up to 10–15% of patients with haemophilia A develop antibodies (inhibitors) to factor VIII treatment