摘要
Fragile X (Fra (X)) syndrome is the most frequent cause of inherited mentalretardation, and it is associated with the fragile site at Xq27.3. In 1991, the FMR1(fragile X mental retardation 1) gene was cloned in the vicinity of this site. The muationand abnormal expression of FMR1 are the direct causes of Fra(X) syndrome. The
基金
Project supported by the State Education Commission and the National Natural Science Foundation of China.
