摘要目的 对20例男性不明原因智力障碍伴癫(癎)患者进行基因筛查,并分析阳性突变携带者的临床特点.方法 收集患儿及其父母的血样,提取基因组DNA,采用目标区序列捕获及第2代测序技术进行候选基因检测,采用聚合酶链反应(PCR)直接测序方法对检测出的阳性基因突变进行验证.结果 20例患儿中,3例患儿存在基因突变,阳性率15％,3例患儿基因突变均为X染色体基因错义突变,分别为:OPHN1基因c.1996C＞G,RAB39B基因c.542C＞T及AFF2基因c.427A＞T,此前均未见文献报道.基因功能分析、氨基酸保守性分析、健康人群发生频率检索、生物信息学预测及核心家系遗传方式检测结果均提示3种突变为有害突变,且突变所在基因均为目前已知X连锁智力障碍伴癫(癎)的相关基因,提示上述3种突变是致病突变的可能性大,或至少可以显著增加男性携带者的患病风险.结论 X染色体关键基因突变/功能异常可能是男性智力障碍伴癫(癎)患儿的重要原因之一,未来X染色体智力障碍相关基因检查应作为男性智力障碍伴癫(癎)患儿的重要检查手段.

abstractsObjective To detect genetic causes of idiopathic mental retardation/developmental delay in 20 male patients with epilepsy and to analyze their clinical characteristics of positive mutation carriers.Methods The families,consisted of the patient and his parents were recruited.Genomic DNA was extracted from peripheral blood,and candidate gene mutation screening was carried out by next-generation sequencing technology.Mutations in positive gene were verified by polymerase chain reaction(PCR) and direct sequencing.Results Three missense mutations were identified among 3 patients out of 20 cases,with a detection rate of 15％.They were:OPHN1 gene c.1996 C ＞ G,RAB39B gene c.542 C ＞ T and AFF2 gene c.427 A ＞ T,none of which had been reported before.All of these mutations were likely to be pathogenic based on gene function,evolutionary conservation,variant frequency in normal population (NHLBI Exome Sequencing Project and 1 000 Genomes),bioinformatics prediction and inheritance patterns.In addition,all 3 genes disrupted were residing on the X chromosome previously demonstrated to be associated with X-linked mental retardation(XLMR),indicating that they were probably pathogenic or might serve as one of the risk factors.Conclusions Abnormal function of genes on the X chromosomal is one of the most impotent causes of XLMR.X chromosomal gene mutation screening would be recommended for male children suffering from idiopathic mental retardation with epilepsy.