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目的探讨产前诊断中非平衡相互易位胎儿的产前诊断指征、临床特征及妊娠结局,为孕妇妊娠选择提供遗传学依据。方法对2011年5月至2016年2月行羊水染色体核型分析并诊断为非平衡相互易位的33例患者的临床资料进行回顾性分析。结果 33例非平衡易位患者中,28例(84.8%,28/33)胎儿超声异常,5例(15.1%,5/33)胎儿超声结果未见异常。7例(21.2%,7/33)为新发突变易位,26例(78.8%,26/33)为父母系遗传易位。7例新发突变的主要产前诊断指征为超声异常5例,高龄2例。26例遗传易位中,双亲之一为易位携带者10例,超声异常8例,高龄5例及不良生育史3例,其中10例(38.5%,10/26)产前检查前双亲之一就已知为易位携带者,16例(61.5%,16/26)为产前检查后确诊。33例均选择终止妊娠,其中28例与超声异常特征相符,5例未见明显表型异常特征。结论产前诊断指征中超声异常与非平衡相互易位紧密相关,异常的染色体易位核型大部分来源于双亲之一平衡易位携带者。非平衡易位胎儿由于涉及染色体大片段的丢失或重复,易导致显著的畸形表型特征,通常均需终止妊娠。
Objective To investigate the prenatal diagnosis indications, clinical characteristics and pregnancy outcome in prenatal diagnosis of unbalanced reciprocal translocation fetus and to provide genetic basis for pregnancy selection. Methods The clinical data of 33 patients who were diagnosed as unbalanced translocation by karyotype analysis of amniotic fluid from May 2011 to February 2016 were analyzed retrospectively. Results Of the 33 patients with unbalanced translocation, 28 (84.8%, 28/33) fetuses had abnormal ultrasound and 5 (15.1%, 5/33) fetuses had no abnormal ultrasound findings. Seven cases (21.2%, 7/33) were new mutations and 26 (78.8%, 26/33) were genetic crosses between parents. Seven cases of new mutations in the main prenatal diagnosis of indications for ultrasound in 5 cases, 2 cases of advanced age. Among 26 cases of genetic translocation, one of the parents was translocation carrier in 10 cases, 8 cases of ultrasound abnormalities in 5 cases, 5 cases of advanced age and 3 cases of poor reproductive history, of which 10 (38.5%, 10/26) prenatal care of parents Once known as a translocation carrier, 16 (61.5%, 16/26) were confirmed for prenatal diagnosis. Totally, 33 cases chose termination of pregnancy, of which 28 cases were consistent with the abnormal features of ultrasound, 5 cases showed no obvious phenotypic abnormalities. Conclusions The prenatal diagnosis indications of ultrasound abnormalities and non-equilibrium reciprocal translocation closely related to abnormal chromosomal translocation karyotype derived mostly from one of the parents of balanced translocation carriers. Unbalanced translocation of the fetus due to the loss or duplication of large chromosomes involved, easily lead to significant deformity phenotype, usually require termination of pregnancy.