Detection of fetal trisomy 9 mosaicism by noninvasive prenatal testing through maternal plasma DNA sequencing

Taiwan J Obstet Gynecol. 2018 Aug;57(4):594-597. doi: 10.1016/j.tjog.2018.06.021.

Abstract

Objective: Noninvasive prenatal testing (NIPT) is widely used as a powerful screening tool to detect common aneuploidies. However, its application for detection of rare chromosomal abnormalities remains inconclusive.

Case report: A 38-year-old woman (gravida 2, para 0) requested NIPT as a primary screening test for fetal aneuploidies at 13 weeks and 1 day of gestation. An unexpected Trisomy 9 (T9) abnormality was highly suspected. Amniocentesis was arranged for further diagnosis at 18 weeks of gestation. Final karyotyping reported 47,XX,+9 [18]/46,XX [12], indicating 60% T9 mosaicism.

Conclusion: This case shows strong evidence that NIPT can be a powerful screening tool to detect rare fetal trisomies at very early gestation.

Keywords: Amniocentesis; Karyotyping; Maternal plasma DNA; Noninvasive prenatal testing; Trisomy 9 mosaicism.

Publication types

  • Case Reports

MeSH terms

  • Abortion, Induced
  • Adult
  • Amniocentesis
  • Chromosomes, Human, Pair 9 / genetics
  • DNA / blood*
  • DNA / chemistry
  • Female
  • Gestational Age
  • Humans
  • Karyotyping
  • Mosaicism
  • Pregnancy
  • Prenatal Diagnosis / methods*
  • Sequence Analysis, DNA*
  • Trisomy / diagnosis*
  • Trisomy / genetics*
  • Ultrasonography, Prenatal
  • Uniparental Disomy / diagnosis*
  • Uniparental Disomy / genetics*

Substances

  • DNA

Supplementary concepts

  • Chromosome 9, trisomy mosaic