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

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

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.

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.

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