一个May—Hegglin异常家系MYH9基因突变新位点研究

A new mutation of MYH9 gene in a May-Hegglin anomaly family

目的鉴定一个May—Hegglin异常家系MYH9基因突变位点。方法报告一个May-Hegglin异常家系的临床及实验室检查资料，包括外周血和骨髓瑞姬染色涂片的细胞形态学检查，静脉血检测肝、肾功能，血小板功能、血块退缩时间及凝血功能，用PCR技术扩增先证者及其母亲的MYH9基因1、10、25、30、38、39、40号外显子，用直接测序的方法分析PCR产物的核苷酸序列。结果先证者及其母亲均有巨大血小板、血小板减少和粒细胞内包涵体，2位患者肝、肾功能，血小板功能、血块退缩时间及凝血功能均正常。此家系患者存在30号外显子第4270位碱基G〉A突变，使第1424位密码子由GAC〉AAC。编码的氨基酸由天冬氨酸转变为天门冬酰胺。而正常对照者无此突变。结论该May—Hegglin异常家系存在30号外显子上Aspl424Asn突变，此突变为中国人May—Hegglin异常家系的首次报道。

Objective To identify a MYH9 gene mutation in a May-Hegglin abnormal family in China. Methods Clinical information and laboratory data of a family of MHA was collected. Cytomorphologic examination of peripheral blood and bone marrow smears were performed with Wrigbt-Giemsa stain. The liver function tests, renal function tests, clot retraction time, platelet function tests and coagulation function tests were performed. The sequences of exons 1, 10, 25, 26, 30, 38,39 and 40 in the MYH9 gene of the two patients and the normal controls were amplified with PCR, and the PCR products were sequenced. Results The proband and his affected mother manifested a typical triad of thrombocytopenia, giant platelets, and inclusion bodies in leukocytes, while their test results of liver function, renal function, clot retraction time, platelet function and coagulation function test were normal. A 4270G→A mutation （GAG→AAG） in the exon 30 of the MYH9 gene existed in the proband and his affected mother, while the same mutation in normal controls could not be found. Conclusions The cases of May-Heggelin anomaly showed typical triad of thrombocytopenia, giant platelets, and inclusion bodies in leukocytes. Mutation of the MYH9 gene exists in exon 30 （Asp1424Asn）in this family and the new point mutation was first reported in China.