PRRT2 c.649C>T突变导致智力障碍以及蛋白质表达异常

PRRT2 c.649C>T mutation leads to mental retardation and abnormal protein expression

目的利用全外显子测序技术寻找1例智力障碍合并癫痫及运动障碍患者的遗传学病因,并探究其致病机制。方法提取患儿及父母双方的外周血DNA,使用外显子测序技术寻找患儿的致病基因,并使用Sanger测序验证致病位点。利用小鼠cDNA诱导克隆该致病基因并构建质粒,采用western blot检测致病基因蛋白与野生型蛋白的表达情况。结果全外显子测序检测发现该患者PRRT2基因存在无义突变(c.649C>T;p.R217X),遗传自母亲;Sanger测序验证结果与外显子捕获测序结果相一致。western blot证实小鼠PRRT2 R223X突变蛋白(对应人PRRT2 R217X)不能正常表达。结论PRRT2基因c.649C>T突变可能是该例患者智力障碍的致病原因。突变的PRRT2 R217X蛋白不能正常表达。

Objective To investigate the genetic etiology of a case of mental retardation complicated with epilepsy and dyskinesia by the whole exome sequencing(WES)technique,and its pathogenic mechanism.Methods The DNAs from peripheral blood cells of the patient and his parents were extracted.Then,the pathogenic genes of the patient were searched by the WES technique,and the pathogenic sites were further verified by Sanger sequencing.Last,the pathogenic gene was cloned by mouse cDNA,and the protein expressed by the pathogenic gene and wild type protein were compared by western blot.Results The WES detected a nonsense mutation of PRRT2 gene(c.649C>T;p.R217X)in the patient,which was inherited from his mother.Sanger sequencing results were consistent with that of WES.western blot confirmed that the mutant protein of mouse Prrt2 R223X,corresponding to human PRRT2 R217X,could not be expressed normally.Conclusion The c.649C>T mutation of PRRT2 gene may be the cause of mental retardation in this patient.The mutant protein PRRT2 R217X cannot be expressed normally.