26例21三体综合征的细胞遗传学分析

摘要:目的　分析21三体综合征患者的染色体核型，探求病因，提出预防与遗传咨询策略。方法　常规外周血淋巴细胞培养方法制备染色体标本，G显带技术进行细胞遗传学分析和遗传咨询。结果　26例确诊的21三体综合征染色体核型中，单纯型23例（占88.46%），嵌合型1例（占3.85%），易位型2例（占7.69%）；26例患儿的母亲在生育患儿时的年龄＞35岁6例（占23.08％），父亲年龄＞39岁5例（占19.23％）；26名患儿中有1位易位型患儿的母亲为罗伯逊平衡易位携带者。结论　21三体综合征是造成小儿先天智力障碍的重要原因，其中单纯型比例最高，易位型和嵌合型较少；其发生与父母年龄、遗传和环境因素相关。细胞遗传学分析是诊断21三体综合征必不可少的方法；产前筛查和遗传优生咨询是降低21三体综合征患儿出生率、提高人口素质的有效手段。

Cytogenetic analysis on 26 cases of Mongolian idiocy

Abstract: Objective Using chromosome karyotype analysis of Mongolian idiocy to explore the cause and puts forward prevention and genetic counseling strategies. Methods Chromosome specimen were prepared using conventional culturing of peripheral blood lymphocytes. G-banding techniques were used in cytogenetic analysis, plus C-banding examinations when necessary, and genetic counseling. Results 26 patients diagnosed with Mongolian idiocy, 23 cases of simplex type (88.46%), 1 cases of chimeric type (3.85%), 2 cases of translocation type (7.69%). In 26 mother, 6 cases of patients were older than 35 years old when delivering (23.08％) and 5 cases of paternal age is more than 39 years old (19.23％). One mother had to Robertson balanced translocation carriers. Conclusion Mongolian idiocy is an important cause of children mental retardation, the highest percentage of simplex, translocation and chimeric less; Its occurrence is related to parents' age, genetic and environmental factors. Cytogenetic analysis is an essential part of syndrome diagnosis method; Prenatal screening and genetic eugenic consultation are an effective means of reducing Mongolian idiocy birth rate and improving the quality of the population.