The FMR-1 gene mutation and Xq27.3 fragile site among 233 non-specific mentally retarded children were investigated in our genetic counseling department and two special educational schools by PCR, Southern Blot hybridization and cytogenetic methods.

• 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。