近来已很明确,有脆性X 染色体fra(X)(q27)的部分女性杂合子显示中等度到严重智力障碍。有人报导培养中的脆性X 频率可能和个体智力状况有关。1982年有人提出智力障碍的程度可能和脆性X 的复制状况有关。已确证在患有Klineferter 综合征的严重智力障碍的男性中有过量的早复制的脆性X 染色体。作者通过对三名有fra(X)(q27)的女性杂合子的淋巴细胞培养,首次报导了杂合子女性中脆性X 染色体非随机失活,并使用了序(?)染色技术,提出了脆性部 It has recently become clear that some female heterozygotes with a fragile X chromosome fra (X) (q27) show moderate to severe mental retardation. It has been reported that the frequency of fragile X in culture may be related to the individual’s mental status. The degree of mental retardation raised in 1982 may be related to the status of fragile X replication. It has been confirmed that there are excessive, early-replicated, fragile X chromosomes in men with severe mental retardation of Klineferter’s syndrome. The authors report the first non-random inactivation of fragile X chromosomes in heterozygous female volunteers by lymphocyte culturing of three female heterozygotes with fra (X) (q27), using the sequential (?) Staining technique, unit