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Case Reports in Genetics
Volume 2015, Article ID 926545, 7 pages
Case Report

Unexplained False Negative Results in Noninvasive Prenatal Testing: Two Cases Involving Trisomies 13 and 18

1Department of Medical Genetics, Division of Biomedical Genetics, University Medical Centre Utrecht, P.O. Box 85090, Mail Stop KC04.084.2, 3508 AB Utrecht, Netherlands
2Department of Obstetrics and Gynecology, University Medical Centre Utrecht, P.O. Box 85090, Mail Stop KE04.123.1, 3508 AB Utrecht, Netherlands

Received 18 March 2015; Accepted 26 May 2015

Academic Editor: Philip D. Cotter

Copyright © 2015 R. Hochstenbach et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Noninvasive prenatal testing (NIPT) validation studies show high sensitivity and specificity for detection of trisomies 13, 18, and 21. False negative cases have rarely been reported. We describe a false negative case of trisomy 13 and another of trisomy 18 in which NIPT was commercially marketed directly to the clinician. Both cases came to our attention because a fetal anatomy scan at 20 weeks of gestation revealed multiple anomalies. Karyotyping of cultured amniocytes showed nonmosaic trisomies 13 and 18, respectively. Cytogenetic investigation of cytotrophoblast cells from multiple placental biopsies showed a low proportion of nontrisomic cells in each case, but this was considered too small for explaining the false negative NIPT result. The discordant results also could not be explained by early gestational age, elevated maternal weight, a vanishing twin, or suboptimal storage or transport of samples. The root cause of the discrepancies could, therefore, not be identified. The couples involved experienced difficulties in accepting the unexpected and late-adverse outcome of their pregnancy. We recommend that all parties involved in caring for couples who choose NIPT should collaborate to clarify false negative results in order to unravel possible biological causes and to improve the process of patient care from initial counseling to communication of the result.