A De Novo Mutation in MYH9 in a Child With Severe and Prolonged Macrothrombocytopenia.

Kun Li, Runming Jin, Wenfu Xu, Yaqing Shen, Ke Lu, Xiaoyan Wu

Journal of pediatric hematology/oncology 2021 Jan

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Congenital macrothrombocytopenia is a diverse group of hereditary disorders caused by mutations in the MYH9 gene, which encodes the nonmuscle myosin heavy chain-A, an important motor protein in hemopoietic cells. Thus, the term MYH9-related disease has been proposed, but the clinicopathologic basis of MYH9 mutations has been poorly investigated. Here, we report a sporadic case of Epstein syndrome, an MYH9 disorder, in a 4-year-old Chinese boy who presented with macrothrombocytopenia. He had no family history of thrombocytopenia, hearing loss, or renal failure. A de novo heterozygous MYH9 mutation, c.287C>T; p. (Ser96Leu), was found in this patient. Genotype-phenotype analysis of all reported mutations suggested a domain-specific relationship between the location of the MYH9 mutation and the penetrance of the nonhematologic characteristics of MYH9-related disorders. Our study highlights the importance of suspecting MYH9-related disease even in cases of chronic macrothrombocytopenia without a family history or extrahematologic symptoms.

Citation

Kun Li, Runming Jin, Wenfu Xu, Yaqing Shen, Ke Lu, Xiaoyan Wu. A De Novo Mutation in MYH9 in a Child With Severe and Prolonged Macrothrombocytopenia. Journal of pediatric hematology/oncology. 2021 Jan;43(1):e7-e10