Familial Thrombotic Thrombocytopenic Purpura in Three Siblings.

Thrombotic thrombocytopenic purpura (TTP) is characterized by microangiopathic hemolytic anemia, systemic platelet aggregation, organ ischemia, thrombocytopenia, and fragmentation of erythrocytes. The disease is caused either by congenital deficiency of von Willebrand factor-cleaving protease (ADAMTS 13) or due to acquired autoantibodies against ADAMTS 13. We have been treating three siblings with recurrent episodes of hemolytic anemia, thrombocytopenia, neurological and renal dysfunctions during last 10 years. The oldest brother presented with thromboangiopathic anemia, thrombocytopenia (platelets account below 30x10³/μl), episode of unconsciousness, proteinuria and splenomegaly at the age of 15 years. Splenectomy was done with the improvement in thrombocytopenic purpura. But he has suffered from permanent microangiopathic hemolytic anemia, and developed renal insufficiency. He died due to intestinal bleeding last year. Two younger siblings, a 12 year old girl and an 11 year old boy also presented with recurrent symptoms of microangipathic hemolytic anemia and thrombopcytopenia with or without renal dysfunction since early childhood. The diagnosis of congenital TTP in this family was based on clinical symptoms and tests of ADAMTS 13 and its inhibitor. The activity of ADAMTS 13 in two younger siblings performed according to the method of Gerritsen et al. was unmeasurable (<3%, reference range 30 – 120%). The ADAMTS 13 inhibitor was undetectable. Both patients are treated with fresh frozen plasma (FFP) infusions every 4 weeks. Precise diagnosis is very important for proper treatment. Only regular FFP infusions as ADAMTS 13 supplementation can assure normal health condition of children with familial TTP.