Thrombotic thrombocytopenic purpura in four siblings

A family is described in which four members of a sibship of seven suffered from a hematologic and systemic disorder whcih has been fatal in three and has been proved at autopsy to have been fatal in three and has been proved at autopsy to have been thrombotic purpura. The fourth member has probably suffered the same disorder. The clinical laboratory and genetic features of the family are discussed at length. No cause of the disorder has been determined.