染色体平衡易位携带者妊娠风险及妊娠结局的研究

Pregnancy outcomes of 194 couples with balanced translocations

目的探讨染色体平衡易位携带者的妊娠风险及其妊娠结局。方法 194例染色体平衡易位携带者,根据平衡易位种类分成相互易位(135例)、非同源罗伯逊易位(52例)、同源罗伯逊易位(7例)3组。调查携带者生育史并随访诊断平衡易位后的妊娠情况,比较各组自然流产、先天缺陷及正常(或)平衡易位后代概率。结果 (1)194对夫妇共妊娠503例次,其中自然流产411例次(81.7%,411/503);产前诊断胎儿异常而终止妊娠16例次(3.2%,16/503);活产缺陷儿36例次(7.2%,36/503);正常(或)平衡易位后代40例次(8.0%,40/503)。(2)相互易位、非同源罗伯逊易位、同源罗伯逊易位3组,活产缺陷儿比率分别为5.7%(20/350)、10.9%(14/128)、8.0%(2/25),3组间相互比较,差异有统计学意义(P<0.05);3组正常(或)平衡易位后代比率分别为6.6%(23/350)、13.3%(17/128)、0,3组间相互比较,差异有统计学意义(P<0.05);而3组自然流产及产前诊断胎儿异常终止妊娠比率比较,差异无统计学意义(P>0.05)。(3)52例次先天缺陷中活产36例次(69%),经产前诊断确诊后引产16例次(31%)。27例次先天缺陷获得细胞遗传学诊断,唐氏综合征发生率为59%(16/27)。(4)相互易位组和非同源罗伯逊易位组共有39对夫妇得到40个正常(或)平衡易位后代,同源罗伯逊易位组无正常(或)平衡易位后代。40个正常(或)平衡易位后代中26个获得产前细胞遗传学诊断,正常核型6个(23%),平衡易位核型20个(77%)。结论染色体平衡易位携带者自然妊娠风险大,尤其同源罗伯逊易位携带者难以获得染色体正常(或)平衡易位的后代。

Objective To investigate the pregnancy outcomes of couples with either maternal or paternal balanced translocations. Methods One hundred and ninety-four couples were divided into three groups based on the kind of translocations： 135 with reciprocal translocation, 52 with nonhomologous Robertsonian translocations, and 7 with homologous Robertsonian translocations. Past reproductive histories were surveyed. For those who wanted to have their own babies by natural conceptions after knowing their karyotypes as well as the risks of abnormal offsprings, subsequent pregnancy outcomes were recorded. Total pregnancy outcomes were compared between three groups. Results （1）503 previous and subsequent pregnancies were recorded in detail. The pregnancy outcomes are as follows： spontaneous abortions 81.7% （411/503）; induced terminations because of fetal abnormalities 3.2% （16/503）;birth defects 7.2% （36/503） ;normal/balanced offsprings 8. 0% （40/503） . In reciprocal translocations, nonhomologous Robertsonian translocations and homologous Robertsonian translocations, the birth defects rates were 5.7% （20/350）, 10. 9% （14/128） and 8. 0% （2/25） , respectively（P 〈0. 05）. The rates of normal/balanced offsprings in each group were 6. 6% （23/350） , 13.28% （ 17/128 ） and 0, respectively （ P 〈 0. 05 ）. The rates of spontaneous abortions as well as the rates of induced terminations among three groups had no statistical differences. （ 2 ） Among the 52 congenital defects, induced terminations accounted for 30. 8% （16/52） , and liveborn 69% （36/52）. Cytogenetic analyses were performed for 27 congenital defects and Down＇s syndrome occupied 59% （ 16/27 ）. （ 3 ） 39 couples with reciprocal or nonhomologous Robertsonian translocations gave birth to 40 normal/balanced offsprings, of which 26 were karyotyped ： normal karyotypes were 6（23% ）and balanced translocations 20（77% ）. Couples with homologous Robertsonian translocations had no normal/balanced offspring. Conclusions Balanced translocation carriers suffer from poor pregnancy prognosis. Couples with homologous Robertsonian translocations have little chance to give birth to normal/ balanced offsprings.