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A full term male was born to a 44yo G16P12 Ashkenazi Jewish mother with a history of anti -phospholipid antibody syndrome.The baby was noted to have severe thrombocytopenia (platelet count of 11K) at birth with a normal white cell count and hemoglobin. None of the baby’s eleven siblings had thrombocytopenia. The neonate had a normal physical exam with the exception of scattered petechiae. The peripheral smear showed reduced, but normal to small sized platelets. Infectious serologies, including CMV, and anti-phospholipid antibodies were negative in the baby. Neonatal alloimmune thrombocytopenia testing was also negative. Random donor platelets were transfused every 3-4 days with good, but short-lived, responses. A bone marrow aspirate was performed on the neonate at nine days of age and showed the presence of scant megakaryocytes of varying morphology (Image). Gene sequencing showed a homozygous c-MPL mutation (intron 1, c.79+2T>A) confirming ta diagnosis of Congenital Amegakaryotic Thrombocytopenia (CAMT).This is a founder mutation that occurs with a carrier frequency of 1 in 75 in Ashkenazi Jews. Both parents were carriers.

Bone marrow aspirate morphology data for Congenital Amegakaryocytic Thrombocytopenia is sparse especially in newborns. Our case shows the presence of megakaryocytes of variable morphology in the bone marrow aspirate of this newborn.