Early diagnosis improves the quality of life in MYH9 disorder

MYH9-macrothrombocytopenia caused by a novel variant (E1421K) initially presenting as apparent neonatal alloimmune thrombocytopenia

MYH9-related disease is a rare cause of thrombocytopenia. We report an infant girl who presented with severe thrombocytopenia at birth and was initially diagnosed with and treated for neonatal alloimmune thrombocytopenia. However, persistent thrombocytopenia led to the suspicion of congenital thrombocytopenia and subsequent identification of a novel variant in MYH9 (E1421K). In silico analysis strongly predicts that this is a disruptive substitution. Immunofluorescent analysis of neutrophils demonstrates abnormal aggregates of MYH9 protein. This case also suggests that a very high immature platelet fraction (≥40%) may be useful for rapidly differentiating MYH9-related disease from other causes of neonatal thrombocytopenia.

Macrothrombocytopenia With Congenital Bilateral Cataracts: A Phenotype of MYH9 Disorder With Exon 24 Indel Mutations

MYH9 disorder is characterized by large platelets and granulocyte inclusion bodies, and can be complicated with young-adult onsets of nephropathy, sensorineural hearing loss, and cataracts. Congenital cataracts in patients with MYH9 disorder is rare, and their etiology has not been elucidated. We report a 3-year-old patient with MYH9 disorder who had a p.E1066_A1072del mutation and developed cataracts congenitally. A review of the literature reveals that patients with an MYH9 exon 24 indel mutation, including p.E1066_A1072del, are susceptible to developing congenital cataracts and should be followed closely for other nonhematological complications.