A Trp33Arg Mutation at Exon 1 of theMYH9Gene in a Korean Patient with May-Hegglin Anomaly

In this report, we describe a Korean patient with May-Hegglin anomaly from a mutation of the MYH9 gene.The proband was a 21-year-old man with thrombocytopenia.He did not have a bleeding tendency.His neutrophil count was normal at 7490/ mm 3 ; however, the neutrophils contained abnormal basophilic inclusions in their cytoplasm.The platelet count was decreased at 15000/mm 3 with giant platelets.Coagulation test results were not remarkable.Direct sequencing of MYH9 revealed that he was heterozygous for a mutation in exon 1, which was a 97T>A substitution mutation affecting codon 33, substituting tryptophan with arginine (Trp33Arg).Family study showed that both of his parents had normal phenotype and genotypes, indicating a de novo occurrence of the mutation in the proband.