妊娠中期产前诊断羊水20-三体假性嵌合体一例  

One case of pseudomosaic trisomy 20 prenatally diagnosed by amniocentesis at second trimester

作　　者：戚庆炜[1] 郝娜[1] 周京[1] 刘俊涛[1] 边旭明[1] 

机构地区：[1]中国医学科学院北京协和医学院北京协和医院妇产科,100730

出　　处：《中华围产医学杂志》2014年第12期822-825,共4页Chinese Journal of Perinatal Medicine

摘　　要：目的：总结妊娠中期羊水20-三体假性嵌合体的产前诊断及遗传咨询的特点。方法对1例妊娠中期羊水20-三体假性嵌合体病例及相关文献进行分析。结果孕妇31岁，妊1产0，妊娠16周时，母体血清学筛查提示胎儿21-三体风险值为1/200，于2012年9月妊娠18周行羊膜腔穿刺术。采用GLP13/GLP21/CSP18/CSPX/CSPY探针的羊水间期细胞荧光原位杂交（fluorescence in situ hybridization，FISH）分析未见异常信号，羊水细胞培养和染色体核型分析结果为47,XY,＋20[7]/46,XY[9]，三体细胞系占7/16。进一步行脐静脉穿刺，脐血染色体核型为46,XY。对羊水间期细胞行D20Z1（20p11.1-q11.1）和D20S1157/20QTEL14（20per/qter）探针的 FISH 分析，各个探针在所有细胞中均只出现2个信号。妊娠24周行系统胎儿超声检查未见异常。综合分析上述情况，考虑该20-三体嵌合体为假性嵌合体。孕妇及其家属决定继续妊娠，至妊娠39周经阴道分娩一男性活婴，儿科体格检查未见异常。该婴儿随访至生后7个月，外观及发育未见异常。取该婴儿外周血查染色体核型为46,XY，同时取其口腔颊黏膜脱落细胞行D20Z1、D20S1157/20QTEL14探针的间期FISH分析，在所有细胞中均只出现2个信号，进一步证实产前诊断的结果。结论对羊水20-三体嵌合体需进行充分评估，对孕妇及配偶进行充分的产前咨询。间期FISH对评估嵌合体具有重要价值。产后应对多种组织行染色体核型分析或间期FISH的复核。Objective To investigate the prenatal diagnosis and prenatal genetic conselling of pseudomosaic trisomy 20. Methods One case of pseudomosaic trisomy 20 was analyzed and relative literatures were reviewed. Results A 31-year-old gravid 1, para 0 woman underwent amniocentesis at 18 weeks of gestation due to high risk of trisomy 21 during maternal serum screening in September, 2012. Interphase fluorescence in situ hybridization （FISH） of amniocytes with probes GLP13/GLP21/CSP18/CSPX/CSPY showed a normal result, while cytogenetic analysis of cultured amniocytes revealed a karyotype of 47,XY,＋20[7]/46,XY[9]. The level of trisomy in the cultured amniocytes was 7/16. Cordocentesis revealed a karyotype of 46,XY in cultured cord blood cells. Interphase FISH analysis was performed using the probes D20Z1 （20p11.1-q11.1） and D20S1157/20QTEL14 （20 per/qter）. Each probe showed two signals in all uncultured amniocytes. The prenatal ultrasound findings were unremarkable. The mosaicism was considered to be pseudomosaicism. After genetic counseling, the parents selected to continue the pregnancy. A healthy male baby was delivered at 39 weeks of gestation. Postnatal cytogenetic analysis revealed a karyotype of 46,XY in peripheral blood lymphocytes. Interphase FISH analysis of the uncultured buccal cast-off cells using the probes D20Z1 and D20S1157/20QTEL14 showed normal results in 100%cells. There was no phenotypic abnormality at the age of seven months. Conclusions When mosaic trisomy 20 is identified in amniocytes, further evaluation＆amp;nbsp;and genetic counseling are required. Interphase FISH of the uncultured amniocytes with a chromosome-specific probe is a useful tool for confirmation of the prenatal diagnosis of mosaicism. Genetic analysis of multiple tissues is required postnatally.

关 键 词：三体性 镶嵌现象 产前诊断 核型分析 原位杂交 荧光 羊膜腔穿刺术 

分 类 号：R714.5[医药卫生—妇产科学]