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
刘国忠 1侯海燕 2常玉 1郝春霞 1睢丽婷1
作者信息
- 1. 300221 天津坤如玛丽妇产医院
- 2. 天津医科大学第二医院
- 折叠
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.
Abstract
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(SNP-array)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Key words
Down syndrome/Trisomy/Chimera/Genetic counseling/Karyotyping/In situ hybridization,fluorescence引用本文复制引用
出版年
2024
国家科技期刊平台
NSTL
万方数据