Copy-number variation and false positive prenatal aneuploidy screening results

N Engl J Med. 2015 Apr 23;372(17):1639-45. doi: 10.1056/NEJMoa1408408. Epub 2015 Apr 1.


Investigations of noninvasive prenatal screening for aneuploidy by analysis of circulating cell-free DNA (cfDNA) have shown high sensitivity and specificity in both high-risk and low-risk cohorts. However, the overall low incidence of aneuploidy limits the positive predictive value of these tests. Currently, the causes of false positive results are poorly understood. We investigated four pregnancies with discordant prenatal test results and found in two cases that maternal duplications on chromosome 18 were the likely cause of the discordant results. Modeling based on population-level copy-number variation supports the possibility that some false positive results of noninvasive prenatal screening may be attributable to large maternal copy-number variants. (Funded by the National Institutes of Health and others.).

Publication types

  • Case Reports
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aneuploidy*
  • Chromosome Disorders / diagnosis*
  • Chromosomes, Human, Pair 13
  • Chromosomes, Human, Pair 18
  • Chromosomes, Human, Pair 21
  • DNA / analysis
  • DNA / blood*
  • DNA Copy Number Variations*
  • False Positive Reactions*
  • Female
  • Humans
  • Models, Statistical
  • Pregnancy
  • Prenatal Diagnosis*


  • DNA