Objective  To analyze the clinical and laboratory abnormalities and genetic defect of inherited thrombocytopenia in a Chinese family.

  Methods  We collected the clinical data and blood samples of a proband and his family members, examined the characteristic morphological features of platelets and leukocytes on blood smears with Wright's-Giemsa staining, observed the ultrastructure of platelet and leukocyte under electron microscope, and detected expression of platelet membrane protein by flow cytometry. Genomic DNA was isolated from the peripheral blood of the proband and 3 members of his family. All the exons and exon-intron boundaries of the MYH9 gene were amplified by polymerase chain reaction (PCR), followed by direct sequencing.

  Results  In the peripheral blood smears, 90% of platelet were large platelets, the expressions of platelet membrane glycoproteins (CD41, CD61, CD42a, CD42b) and platelet function were within the normal range. Electron microscope showed no capsule separating the inclusion bodies in neutrophil cytoplasmic. A heterozygous G to A mutation was found in the proband and two members of his family at nucleotide 5521 in exon 38 of MYH9 gene, leading to the encoding of non-myosin heavy chain A (NMMHC2A) No. 1841 of glutamate into lysine.

  Conclusion  MYH9 gene mutation and thrombocytopenia and giant platelets are the main features of Fechtner syndrome.