Haemophilia is a genetic bleeding disorder that affects the ability of the blood to clot. It is caused by a deficiency or absence of certain clotting factors in the blood, which are essential for normal blood clotting. Haemophilia is classified into two types, haemophilia A and haemophilia B, depending on the specific clotting factor that is deficient. Haemophilia A is caused by a deficiency of clotting factor VIII, while haemophilia B is caused by a deficiency of clotting factor IX. People with haemophilia are at risk for excessive bleeding and bruising, even from minor injuries. They may also experience spontaneous bleeding episodes, particularly into the joints, which can cause pain, swelling, and limited range of motion. Haemophilia is a lifelong condition that requires careful management and regular monitoring. Treatment typically involves replacement therapy with clotting factors, which can be administered through injections or infusions. In some cases, gene therapy may be used to treat haemophilia by introducing a functional copy of the missing clotting factor gene into the patient's cells. Haemophilia is a rare condition that affects approximately 1 in 10,000 people worldwide. It is typically inherited in an X-linked recessive pattern, which means that it is passed down from mothers to their sons.