{"title":"[Non-invasive prenatal screening in three cases of vanishing twin syndrome and a literature review].","authors":"Xinni Shu, Jiexia Yang, Yousheng Wang, Zhuanping Zhang, Fangfang Guo, Haishan Peng, Dongmei Wang, Yaping Hou","doi":"10.3760/cma.j.cn511374-20240603-00336","DOIUrl":null,"url":null,"abstract":"<p><strong>Objective: </strong>To assess the impact of vanishing twin syndrome (VTS) on the accuracy of non-invasive prenatal testing (NIPT).</p><p><strong>Methods: </strong>Three pregnant women who underwent NIPT testing at Guangdong Women and Children's from November 2019 to February 2020 were selected as the study subjects. The three women had either vanish twin syndrome or had undergone fetal reduction for other reasons in one of their twins, and were subsequently subject to NIPT, chromosome karyotyping, chromosome microarray analysis (CMA), and short tandem repeat (STR) analysis. This study has been approved by the Medical Ethics Committee of Guangdong Maternal and Child Health Hospital (Ethics No.: 20230132).</p><p><strong>Results: </strong>Case 1 underwent selective fetal reduction at 8<sup>+</sup> weeks of gestation. At 17<sup>+</sup> weeks, NIPT showed a fetal DNA fraction of 2.806%, with results indicating the presence of Y chromosome and abnormal sex chromosome ratios. However, the women had subsequent uncomplicated vaginal delivery of a female infant, and no abnormality noted. Case 2 experienced spontaneous demise of one twin at 13 weeks' gestation. At 19 weeks, NIPT indicated a high risk for chromosome 21 (Z-score 4.671) in the surviving fetus, but subsequent evaluation showed no abnormality. Case 3, a dichorionic diamniotic (DCDA) twin pregnancy, underwent selective reduction at 13<sup>+</sup> weeks due to fetal abnormalities in one twin. At 22<sup>+</sup> weeks, NIPT for the surviving fetus indicated a high risk for chromosome 21 (Z-score 17.549), but subsequent evaluation was unremarkable.</p><p><strong>Conclusion: </strong>In twin pregnancies, the relatively low cell-free fetal DNA (cffDNA) concentration can compromise the success rate and accuracy of NIPT compared to singleton pregnancies. Residual DNA from the demised fetus may persist for weeks following VTS or selective reduction, potentially causing false-positive NIPT results and interfering with sex chromosome prediction for the surviving fetus. Additionally, determining chorionicity is critical for reliable interpretation of NIPT results in twin pregnancies.</p>","PeriodicalId":39319,"journal":{"name":"中华医学遗传学杂志","volume":"42 7","pages":"855-861"},"PeriodicalIF":0.0000,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"中华医学遗传学杂志","FirstCategoryId":"3","ListUrlMain":"https://doi.org/10.3760/cma.j.cn511374-20240603-00336","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"Medicine","Score":null,"Total":0}
引用次数: 0
Abstract
Objective: To assess the impact of vanishing twin syndrome (VTS) on the accuracy of non-invasive prenatal testing (NIPT).
Methods: Three pregnant women who underwent NIPT testing at Guangdong Women and Children's from November 2019 to February 2020 were selected as the study subjects. The three women had either vanish twin syndrome or had undergone fetal reduction for other reasons in one of their twins, and were subsequently subject to NIPT, chromosome karyotyping, chromosome microarray analysis (CMA), and short tandem repeat (STR) analysis. This study has been approved by the Medical Ethics Committee of Guangdong Maternal and Child Health Hospital (Ethics No.: 20230132).
Results: Case 1 underwent selective fetal reduction at 8+ weeks of gestation. At 17+ weeks, NIPT showed a fetal DNA fraction of 2.806%, with results indicating the presence of Y chromosome and abnormal sex chromosome ratios. However, the women had subsequent uncomplicated vaginal delivery of a female infant, and no abnormality noted. Case 2 experienced spontaneous demise of one twin at 13 weeks' gestation. At 19 weeks, NIPT indicated a high risk for chromosome 21 (Z-score 4.671) in the surviving fetus, but subsequent evaluation showed no abnormality. Case 3, a dichorionic diamniotic (DCDA) twin pregnancy, underwent selective reduction at 13+ weeks due to fetal abnormalities in one twin. At 22+ weeks, NIPT for the surviving fetus indicated a high risk for chromosome 21 (Z-score 17.549), but subsequent evaluation was unremarkable.
Conclusion: In twin pregnancies, the relatively low cell-free fetal DNA (cffDNA) concentration can compromise the success rate and accuracy of NIPT compared to singleton pregnancies. Residual DNA from the demised fetus may persist for weeks following VTS or selective reduction, potentially causing false-positive NIPT results and interfering with sex chromosome prediction for the surviving fetus. Additionally, determining chorionicity is critical for reliable interpretation of NIPT results in twin pregnancies.
期刊介绍:
Chinese Journal of Medical Genetics is a medical journal, founded in 1984, under the supervision of the China Association for Science and Technology, sponsored by the Chinese Medical Association (hosted by Sichuan University), and is now a monthly magazine, which attaches importance to academic orientation, adheres to the scientific, scholarly, advanced, and innovative, and has a certain degree of influence in the industry.
Chinese Journal of Medical Genetics is a journal of Peking University, and is now included in Peking University Journal (Chinese Journal of Humanities and Social Sciences), CSCD Source Journals of Chinese Science Citation Database (with extended version), Statistical Source Journals (China Science and Technology Dissertation Outstanding Journals), Zhi.com (in Chinese), Wipu (in Chinese), Wanfang (in Chinese), CA Chemical Abstracts (U.S.), JST (Japan Science and Technology Science and Technology), and JST (Japan Science and Technology Science and Technology Research Center). ), JST (Japan Science and Technology Agency), Pж (AJ) Abstracts Journal (Russia), Copernicus Index (Poland), Cambridge Scientific Abstracts, Abstracts and Citation Database, Abstracts Magazine, Medical Abstracts, and so on.