Abstract
We report the case of a 1-day-old boy admitted to our neonatal intensive care unit for initial vomiting with thrombocytopenia. His platelet count was reduced to 3.0×104/μL. At first, neonatal alloimmune thrombocytopenia was suspected, but the corresponding antibody was not detected. His thrombocytopenia was persistent, and giant platelets were first observed when he was 17 months old. Since a genetic test revealed GPIX gene mutation, he was diagnosed as having Bernard-Soulier syndrome (BSS). He is a compound heterozygote for a known p.Cys89Tyr mutation and a novel p.Gly40fsX43 mutation of one base deletion resulting in a frameshift and premature termination. Because he is diagnosed in his early infancy, he will be provided guidance about lifestyle when he is old enough to understand and managed appropriately when he bleeds. Neonatal alloimmune thrombocytopenia is a relatively frequent cause of neonatal thrombocytopenia without complications, but some congenital thrombocytopenia syndromes such as BSS are rare. It is important to carefully observe the platelet morphology when diagnosing thrombocytopenia.
