906 A FAMILY WITH AN INHERITED PLATELET STORAGE POOL DEFECT ASSOCIATED WITH A HIGH INCIDENCE OF MYELOPROLIFERATIVE DISORDERS

Abstract

A boy, age 5, presented with easy bleeding since birth and was found to have a long bleeding time, thrombocytopenia and abnormal platelet function (absent second wave aggregation with epinephrine, decreased aggregation to collagen but a normal first wave response to ADP and normal aggregation to arachidonic acid). His bone marrow was normal. At age 6½ years this boy developed progressive anemia, thrombocytopenia and splenomegaly, and was diagnosed as having juvenile chronic myelogenous leukemia. This child's father, grandfather and two of the grandfather's sisters were found to have a similar bleeding defect with a long bleeding time, mild thrombocytopenia, abnormal aggregation pattern similar to the propositus, and deficiency of platelet ADP, serotonin and dense bodies. Thrombin-induced arachidonic acid release, conversion of arachidonic acid to thromboxane B2 and phosphorylation of platelet proteins were normal. One of the grandfather's sisters with a lifelong bleeding tendency and a platelet storage pool deficiency documented at age 38, developed myelomonocytic leukemia at age 41. Another sister and a brother of the grandfather, bleeding history uncertain, died at ages 8 and 23 of leukemia. The great grandmother and her sister both with lifelong bleeding histories had died of leukemia. The findings suggest this family has an inherited platelet storage pool deficiency associated with an increased susceptibility to the development of a myeloproliferative disorder.