先天性智能发育不全患儿的细胞遗传学研究

用低叶酸培养基（ＴＣ１９９）对９０例先天性智能发育不全（ＭＲ）患儿的外周血淋巴细胞进行了Ｇ显带分析及脆性Ｘ染色体研究。发现１９例染色体异常患者，占２１．１１％。其中先天愚型１４例，占１５．５６％；其它常染色体结构异常２例；性染色体异常１例；脆性Ｘ染色体２例，占２．２２％。结果表明对ＭＲ进行细胞遗传学研究时，不仅要注意染色体数目及结构的异常，尤应进行脆性Ｘ染色体的检测。本文首次证明脆性Ｘ综合征在本地区的存在，在ＭＲ中所占的比例与国外报道大致相同。脆性Ｘ染色体的诱导方法进行了讨论。还发现１例ＭＲ患儿，核型为４６，ＸＹ，ｔ（５；１５）（ｐ１５；ｑ１３），经鉴定为世界首报核型。

CYTOGENETIC STUDY OF THE CHILDREN WITH CONGENETAL MENTAL RETARDATION

After cultured in folate acid deficient medium, the peripheral blood lylmpho-cytes of 90 mental retarded children were studies by G banding and fragile X chromosomeanalysis.Of the 9 mental retarded children with chromosome abnomalities(2l.11%),14 hadDown′s syndrome(15.56%);2 had other autosomal chromosome structural abnomality; 1had sex chromosome abnomality;2 had fragile X syndrome(2.22%).We noticed not onlynumber and structural abnomality but also the fragile X chromosome with the cytogeneticstudy on mental retarded children.Fragile X syndrome was first discoved in this area and theincidence in the mental retarded children was concordance with it reported in foreign litera-ture. In this paper,we discussed the fragile X induction method and discoved one mental re-tarded with the Karyotype 46,XY,t(5;15)(p15;q13).This Karyotype is first reported in theworld.