脆性X综合征(fragile X syndrome,FXS)是一种呈X连锁的遗传性智力低下疾病,其发病率较高,国内报道发病率约为1/1250,在弱智人群中的发病率为6.8%[1]。临床上本病主要表现为程度不等的智力低下(mental retardation,MR),患者在婴幼儿期发育迟缓,表现出认知,交流和行为障碍。此外,典型男性患者还具有特殊的外貌特征。1991年Verkerk Fragile X syndrome (FXS) is an X-linked hereditary mental retardation with a high prevalence, with a reported incidence of approximately 1 in 1250 in the country and an incidence of 6.8% in the mentally handicapped [1]. The clinical manifestations of the disease mainly for varying degrees of mental retardation (mental retardation, MR), patients in infancy and young age, showing cognitive, communication and behavioral disorders. In addition, typical male patients also have special appearance characteristics. 1991 Verkerk