Schaar (1963) described 4 brothers with idiopathic thrombocytopenic purpura that appeared in early infancy and was symptomatic. Three of the boys were well 14 years, 6 years, and 3 years following spenectomy. The other brother died of pneumococcal ... Schaar (1963) described 4 brothers with idiopathic thrombocytopenic purpura that appeared in early infancy and was symptomatic. Three of the boys were well 14 years, 6 years, and 3 years following spenectomy. The other brother died of pneumococcal septicemia 3.5 years after splenectomy. The disorder was not associated with any other blood dyscrasia, platelet antibodies, or maternal antibodies. A platelet-stimulating factor was present. Bloom et al. (1966) described a form of constitutional aplastic anemia with 'amegakaryocytic thrombocytopenia present at birth or early infancy, followed later in childhood by pancytopenia.' They called it type II constitutional aplastic anemia. Maternal-fetal incompatibility of platelet antigens was a cause of neonatal thrombocytopenia in multiple sibs (Paganelli, 1969), simulating recessive inheritance. These patients were chronically thrombocytopenic but responded to the transfusion of normal plasma. Autosomal recessive inheritance has been reported by Roberts and Smith (1950) and by Wilson et al. (1963).