染色体异染色质区变异特征及其遗传效应的研究

Study on the Mutation in Chromosome Heterochromatic Region and its Genetic Effects

目的:探讨4种异染色质区变异的遗传特征,对表型、生殖、生育异常影响的遗传效应及遗传咨询对策。方法:对习惯性流产患者进行细胞遗传学检测,并对950例有异染色质区变异者的临床资料和文献资料进行统计学处理和分析。结果:在异染色质区变异群体中,男性Yqh±出现频率最高,为82.74%,1qh±、9qh±和16qh±频率较低,分别为4.74%,6.63%和5.89%,女性1qh±明显高于男性。1qh±、9qh±、16qh±和Yqh±的个体大多表型正常,其频率分别为97.78%,95.16%,66.67%和82.08%,导致表型异常的频率较低,但导致流产的频率明显增高,分别为60.78%,53.45%,69.23%,47.94%,其次是导致不孕不育,导致子女异常和死胎的频率较低。结论:在4种异染色质区变异类型中,Yqh±频率和导致生育异常的效应明显高于其他3种;4种异染色质区变异对表型的有害效应不明显,少数个体有表型异常,其主要有害遗传效应是导致流产和不孕不育,少数可导致子女异常。提示对习惯性流产、不孕不育、已生育异常子女和有表型异常个体应同时进行G带和C带检测,并注重分析异染色质区变异,对有变异者建议生育时做产前诊断。

Objective ： To explore the genetic characteristics of 4 types of mutations in heterochromatic regions and their genetic effects on phenotype, reproduction and abnormal birth, as well as the strategy of genetic counseling. Methods ： Cytogenetic detection was performed in patients with habitual abortion. The clinical data of 950 cases with mutations in chromosome heterochromatic regions were processed and analyzed statistically. Results： Among the male cases with mutations in heterochromatic regions, Yqh^ ±occurred with the highest frequency （82.74%）, and the occurrence frequencies of 1qh^ ± , 9qh^ ± and 16qh^ ± were 4.74%, 6.63% and 5.89%, respectively. The occurrence frequency of 1 qh ^ ± in females was higher than that of males. The phenotypes of cases with lqh^ ± , 9qh^ ± , 16qh^ ± and Yqh^ ± were mostly normal, with the frequencies of 97.78%, 95. 16%, 66.67%, and 82.08%, respectively. Compared with the fewer abnormal phenotypes, the most harmful impact of mutations was abortions, with the frequencies of 60.78%, 53.45%, 69.23% and 47.94%, respectively. The next harmfulness was sterility induced by mutations, and the frequencies of abnormal children as well as dead foetus were lower. Conclusion： Among the 4 types of mutations in heterochromatic regions, the occurrence frequency and genetic effects of abnormal reproduction of Yqh ^ ± are significantly higher than the other 3 types. The harmful effects of mutations in heterochromatic regions on phenotype are not so obvious. The main harmful genetic effects of mutations are abortion and sterility, as well as few abnormal children. It is suggested that the detection of G - band and C - band should be performed in individuals with habitual abortion, infertility, abnormal children and abnormal phenotype. More attentions should be paid to mutations in heterochromatic regions, and prenatal diagnosis is suggested for individuals with mutations before pregnancy.