采用PCR、Southern Blot印迹杂交及细胞遗传学方法,对233名原发性智力低下患儿进行了FMR-1基因的突变分析和Xq27.3脆性位点检查。结果:确诊9名脆性X综合征患者,占3.86％,并在部分家庭成员中检出了女性前突变和全突变携带者,排除细胞学方法假阳性1例。PCR方法简便迅速,成本低,较细胞学方法更具优越性,适于临床普及应用和人群筛查,是遗传咨询中的有效检查手段。 Using PCR, Southern Blot blotting and cytogenetic analysis, 233 children with primary mental retardation were analyzed for the mutation of FMR-1 gene and Xq27.3 fragile locus. Results: Nine cases of Fragile X syndrome were diagnosed, accounting for 3.86%. Pre-female and full-mutation carriers were detected in some family members, and 1 case of cytology false positive was excluded. PCR method is simple and rapid, low cost, more superior cytology methods, suitable for clinical application and crowd screening, genetic counseling is an effective means of inspection.