Familial cases with MYH9 disorders caused by MYH9 S96L mutation.

We report familial cases with MYH9 disorders: a 1-year-old Japanese boy who presented only with macrothrombocytopenia, and his 33-year-old father who had been diagnosed with refractory chronic idiopathic thrombocytopenic purpura, and suffered from hearing loss and chronic renal failure. Peripheral blood smears revealed giant platelets but no Döhle body-like cytoplasmic inclusion bodies in neutrophils. Heterozygous MYH9 S96L mutations were found in the patient and his father, resulting in the diagnosis of a familial case with MYH9 disorders. The possibility of MYH9 disorders including Epstein syndrome should be assessed in cases of thrombocytopenia through the careful examination of hematological features.