[Nonmuscle myosin heavy chain 9 gene mutations related disease: a family report].

Objective: To improve the recognition of nonmuscle myosin heavy chain 9 gene (MYH9) mutations related disease.

Methods: Clinical information and laboratory data of a family of MYH9-related disease was reported. Cytomorphology examination of peripheral blood and bone marrow smears were stained with Wright-Giemsa stain. Ultrastructural studies of peripheral blood were carried out. Surface expression of platelet glycoproteins was investigated by flow cytometry. The MYH9 mRNA was isolated from EBV-transformed peripheral blood leukocytes and analyzed by reverse-transcription-polymerase chain reaction (RT-PCR) and direct sequencing. Meanwhile, mutation analysis of the MYH9 gene was performed by PCR and direct sequencing.

Results: Both the patient and his father had large platelets, thrombocytopenia and characteristic granulocyte inclusion bodies (Dohle-like bodies). Platelet glycoproteins (GPIb) of the patient and his father were also slightly lower than normal. In the patient, a heterozygous mutation (5797C>T) in the MYH9 gene was detected both at the RNA level and the genomic DNA level. His father carried the same mutation.

Conclusion: Patient and his father both had giant platelets, thrombocytopenia, leukocyte inclusions and mutation of MYH9. The diagnosis of MYH9-related disease was established.