脆性X综合征是一种发病率仅次于唐氏综合征的人类遗传性智力低下疾病 ,其发病率在男性群体为 0 .0 4 %～0 .0 8% ,在女性群体为 0 .0 2 %～ 0 .0 6 %。本病的临床表现除了有程度轻重不等的智力低下外 ,尚有其他体格和生理行为异常 ,包括颜面狭长、前额及下颌突出、招风耳、浆液 Fragile X syndrome is a disease of human genetic mental retardation, second only to Down’s syndrome, with a prevalence of 0.04% -0.08% in the male population and 0 .0 in the female population 2% ~ 0. 06%. In addition to the clinical manifestations of this disease, ranging from the severity of mental retardation, there are other physical and physiological abnormalities, including the face of long, prominent forehead and jaw, strokes ears, slurry