Hemophilia: An Updated Review

Introduction Hemophilia is a genetic disorder that results in either an inactive or inadequate supply of a plasma protein needed for normal blood clotting. The two most common forms are hemophilia A and B, caused by a defect or deficiency in clotting factors VIII and IX, respectively. Both types are X-linked recessive disorders characterized by prolonged bleeding and hemorrhages, typically into joints and soft tissues. Hemophilia C is an autosomal recessive defect that results in a deficiency of factor XI. Marked by bleeding in mucous membranes, hemophilia C exhibits a somewhat different clinical pattern of hemorrhaging than hemophilia A or B but similar to that in von Willebrand disease. This review will focus on hemophilia A and B. Hemophilia has served as a model for the treatment of chronic illness through the comprehensive approach to care. If a child who has hemophilia is managed appropriately with early factor replacement therapy and attempts to avoid the long-term consequences of bleeding, the prospects for a long, full, and healthy life are very good. Epidemiology/Genetic Transmission The incidence of hemophilia A and B is about 15 to 20 per 100 000 males born worldwide and occurs in all races and socioeconomic groups. Hemophilia A, also known as classical accounts for about 80% of cases of hemophilia, occurs in one of 10 000 male births, and affects about 17 500 individuals in North America.