半合子脆性X 染色体[以下简称fra(X)(q)]与智力低下之关系已相当明确,但对不同群体中杂合子和半合子fra(x)(q)的总频率所知甚少。至今还没有关于在未经选择的一般儿童、青年和成人群体中筛选fra(X)(q)的报导,仅有少数报告涉及经选择的智力低下男性中进行fra(X)(q)的筛选。本文进一步提供在智力低下群体中筛查fra(X)(q)频率的资料。作者在德国北部一所专门的研究机构,选择242名中(?)重度智力低下的男性,年龄为5(?)60岁,智商(IQ)范围为重度～临 The relationship between hemizygous fragile X chromosome [hereinafter referred to as fra (X) (q)] and mental retardation has been fairly well defined but little is known about the overall frequency of heterozygotes and hemizygous fra (x) (q) in different populations. There have been no reports of screening for fra (X) (q) in unselected general children, adolescents and adults, and only a few reports on screening of fra (X) (q) among selected men with mental retardation . This article further provides information on the frequency of fra (X) (q) screening in people with mental retardation. The author, a specialized research institution in northern Germany, selected 242 middle-aged men with severe mental retardation who were aged 60 (?) And 60 (IQ)