表型正常母亲二次孕育21-三体综合征患儿的遗传学分析  

Genetic Analysis of Second Pregnancy with A Child of 21-Trisomy Syndrome in A Phenotypically Normal Mother

作　　者：刘国忠 侯海燕 常玉 郝春霞 睢丽婷 LIU Guo-zhong;HOU Hai-yan;CHANG Yu;HAO Chun-xia;SUI Li-ting(Tianjin Congra Maire Women and Children′s Hospital,Tianjin 300221,China;The Second Hospital of Tianjin Medical University,Tianjin 300211,China)

机构地区：[1]天津坤如玛丽妇产医院,300221 [2]天津医科大学第二医院

出　　处：《国际生殖健康／计划生育杂志》2024年第4期305-308,327,共5页Journal of International Reproductive Health/Family Planning

基　　金：国家自然科学基金(81402691)。

摘　　要：母亲表型正常而反复孕育21-三体综合征患儿的病例非常罕见,临床上要考虑母亲染色体嵌合体的可能。报告1例表型正常孕妇既往4次妊娠早期胚胎停育,其中2次胚胎染色体均为47,XY,+21。夫妻双方染色体正常(计数20个分裂象)。此次妊娠无创产前筛查(noninvasive prenatal testing,NIPT)和扩展型NIPT均提示21-三体高风险,羊水穿刺单核苷酸多态性微阵列(single nucleotide polymorphism array,SNP-array)结果为[arr(1-22)×2,(XN×1)],胎儿羊水染色体核型为46,XN。复查夫妻双方外周血染色体(计数50个分裂象),确诊孕妇染色体为47,XX,+21[4]/46,XX[46],嵌合比例在7%~8%,孕妇外周血染色体荧光原位杂交(fluorescence in situ hybridization,FISH)检测计数100个细胞,7个21-三体,即7%的细胞为21-三体。胎儿羊水FISH检测计数100个细胞均未见21-三体。最终于孕40+1周剖宫产娩一健康女婴。该病例母亲染色体核型为21-三体嵌合型是导致连续2次孕育21-三体综合征患儿的原因。The repeated pregnancies with 21-trisomy syndrome in a phenotypically normal mother are rare,and the possibility of maternal chromosomal mosaic should be considered.We report a woman with normal phenotype who had a history of early embryo loss for 4 times,two of which the karyotypes were 47,XY,+21.The couple′s karyotypes were normal(counting 20 split phases).Both noninvasive prenatal testing(NIPT)and extended NIPT results refer to a high risk of trisomy 21,and the amniocentesis single nucleotide polymorphism array(SNParray)result was[arr(1-22)×2,(XN×1)],and the fetal amniotic fluid karyotype was 46,XN.The repeated peripheral blood chromosomes test for the couple(counting 50 split phases)was performed,the maternal chromosome karyotype was diagnosed as 47,XX,+21[4]/46,XX[46],with a mosaic ratio of 7%-8%.Maternal fluorescence in situ hybridization(FISH)assay in 100 counted cells showed 7 trisomy 21 cells,suggesting that 7%of the cells were trisomy 21.Fetal amniotic fluid FISH test found no 21-trisomy cell.A healthy baby girl was delivered by cesarean section at 40+1 weeks of gestation.In this case,maternal karyotype of a mosaic 21-trisomy cell/normal cell phenotype may contribute to the twice early pregnancy losses with 21-trisomy syndrome.

关 键 词：唐氏综合征 三体性 嵌合体 遗传咨询 核型分析 原位杂交 荧光 

分 类 号：R714.5[医药卫生—妇产科学]