OBJECTIVETo analyze the clinical manifestations and mutation of MYH9 gene in a large Chinese family affected with MYH9-related thrombocytopenia.

METHODSAfter informed consent was obtained; clinical examination and history investigation was performed on 29 members of the family. DNA was extracted using a standard method, then exons 1 to 40 and their corresponding exon-intron junctions of the MYH9 gene were amplified with PCR and subjected to Sanger sequencing. The results were compared to reference sequence from the University of California, Santa Cruz (UCSC) to screen the mutation. PCR and Sanger sequencing was performed on genome DNA of all family members to confirm the identified mutation.

RESULTSThe clinical manifestations of family members were prominently heterogeneous. Four affected members showed hearing loss or deafness, two affected members showed nephritis or kidney failure, and other affected members was only characterized by mild bleeding or with no obvious symptoms. A heterozygous missense mutation c.4270G>A (p.Aspl841Asn) in exon 30 of the MYH9 gene was identified in all affected members from this family, which also co-segregated with the phenotype.

CONCLUSIONA missense mutation c.4270G>A (p.Aspl841Asn) within the exon 30 of the MYH9 gene was identified to be associated with MYH9-related thrombocytopenia in a Chinese family.