MYH9 disorder: Identification and a novel mutation in patients with macrothrombocytopenia

Pediatr Blood Cancer. 2021 Jul;68(7):e29055. doi: 10.1002/pbc.29055. Epub 2021 Apr 15.

Abstract

The diagnosis of MYH9 disorder is guided by recognizing granulocyte Döhle body-like inclusion bodies and large/giant platelets in the peripheral blood smear. Immunofluorescence study of nonmuscle myosin heavy chain IIA is a sensitive screening method for diagnosis of MYH9 disorder. The diagnosis can then be confirmed by genetic analysis. A total of 67 patients with macrothrombocytopenia were included, of which 11 patients (16%), aged 4 months to 22 years, were ultimately diagnosed with MYH9 disorder. One novel mutation in exon 30 at c.4338T>C (p.F1446A) was detected. This mutation was associated with nonhematologic manifestations presenting in late adolescence with cataracts, hearing loss, and hematuria.

Keywords: MYH9 disorder; macrothrombocytopenia; novel pathogenic MYH9 variant.

MeSH terms

  • Adolescent
  • Blood Platelet Disorders*
  • Child
  • Child, Preschool
  • Cytoskeletal Proteins
  • Hearing Loss, Sensorineural* / diagnosis
  • Hearing Loss, Sensorineural* / genetics
  • Humans
  • Infant
  • Molecular Motor Proteins / genetics
  • Mutation
  • Myosin Heavy Chains / genetics*
  • Thrombocytopenia* / diagnosis
  • Thrombocytopenia* / genetics
  • Young Adult

Substances

  • Cytoskeletal Proteins
  • MYH9 protein, human
  • Molecular Motor Proteins
  • Myosin Heavy Chains