Thrombocytopenia with absent radii. A review of 100 cases.

The syndrome of thrombocytopenia with absent radii (TAR) is a rare congenital syndrome in which the characteristic hematological findings are hypomegakaryocytic thrombocytopenia, periodic leukemoid reactions, and eosinophilia. The thrombocytopenia usually presents at birth or during the neonatal period and may be profound, accounting for significant morbidity. However, resolution of the thrombocytopenia usually occurs after the first year. In this review of 100 cases, the clinical manifestations, pathophysiology, genetics, and treatment are discussed in detail. With the increased understanding of the natural history and pathophysiology of the hypomegakaryocytic thrombocytopenia in the TAR syndrome, in conjunction with the advances in supportive therapy discussed, the outlook for patients with this syndrome has become quite good.