Prenatal diagnosis of mosaic trisomy 16 by amniocentesis in a pregnancy associated with abnormal first-trimester screening result (low PAPP-A and low PlGF), intrauterine growth restriction and a favorable outcome.

Abstract

OBJECTIVE:

We present prenatal diagnosis of mosaic trisomy 16 by amniocentesis in a pregnancy associated with an abnormal first-trimester screening result, intrauterine growth restriction (IUGR) and a favorable outcome.

CASE REPORT:

A 27-year-old woman underwent amniocentesis at 18 weeks of gestation because of an abnormal first-trimester screening result with maternal serum free β-hCG of 1.474 multiples of the median (MoM), pregnancy associated plasma protein-A (PAPP-A) of 0.122 MoM and placental growth factor (PlGF) of 0.101 MoM, and a Down syndrome risk of 1/45. Amniocentesis revealed a karyotype of 47,XY,+16 [9]/46,XY [16] and an abnormal array comparative genomic hybridization (aCGH) result of arr (16) × 3 [0.54] compatible with 54% mosaicism for trisomy 16 in uncultured amniocytes. At 24 weeks of gestation, repeat amniocentesis revealed a karyotype of 47,XY,+16 [4]/46,XY [16] and an aCGH result of arr 16p13.3q24.3 (96,766-90,567,357) × 2.25 with a log2 ratio = 0.2 compatible with 20-30% mosaicism for trisomy 16 in uncultured amniocytes. Quantitative fluorescent polymerase chain reaction (QF-PCR) excluded uniparental disomy (UPD) 16. Interphase fluorescence in situ hybridization (FISH) analysis on uncultured amniocytes revealed 19.4% (12/62 cells) mosaic trisomy 16. Prenatal ultrasound revealed IUGR. At 36 weeks of gestation, a phenotypically normal baby was delivered with a body weight of 1900 g. The cord blood had a karyotype of 46,XY. QF-PCR analysis confirmed biparentally inherited disomy 16 in the cord blood and maternal-origin of trisomy 16 in the placenta. When follow-up at age two months, FISH analysis on 101 buccal mucosal cells and 32 urinary cells revealed no signal of trisomy 16.

CONCLUSION:

Mosaic trisomy 16 at amniocentesis can be associated with IUGR and an abnormal first-trimester screening result with low PAPP-A and low PlGF. Mosaic trisomy 16 without UPD 16 at amniocentesis can have a favorable outcome, and the abnormal triosmy 16 cell line may disappear after birth.

• Authors: Chih-Ping Chen, Fei-Hua Lan, Schu-Rern Chern, Peih-Shan Wu, Shin-Wen Chen, Fang-Tzu Wu, Chen-Chi Lee, Meng-Shan Lee, Chen-Wen Pan, Yun-Yi Chen, Wayseen Wang
• Journal: Taiwanese journal of obstetrics & gynecology (Taiwan J Obstet Gynecol) Vol. 60 Issue 6 Pg. 1107-1111 (Nov 2021) ISSN: 1875-6263 [Electronic] China (Republic : 1949- )
• PMID: 34794747 (Publication Type: Case Reports)
• Copyright: Copyright © 2021. Published by Elsevier B.V.

Chemical References

• Placenta Growth Factor
• Pregnancy-Associated Plasma Protein-A

Topics

• Adult
• Amniocentesis (methods)
• Chromosomes, Human, Pair 16
• Comparative Genomic Hybridization
• Female
• Fetal Growth Retardation (diagnosis, genetics)
• Humans
• In Situ Hybridization, Fluorescence
• Infant, Newborn
• Mosaicism
• Placenta Growth Factor (blood)
• Pregnancy
• Pregnancy Outcome
• Pregnancy Trimester, First
• Pregnancy-Associated Plasma Protein-A (analysis)
• Prenatal Diagnosis (methods)
• Trisomy (diagnosis)
• Uniparental Disomy