Cytogenetic discrepancy between cultured amniocytes and uncultured amniocytes in mosaic double trisomy involving trisomy 7 and trisomy 20 (48,XY,+7,+20) at amniocentesis

Chih-Ping Chen; Yi-Hui Lin; Schu-Rern Chern; Peih-Shan Wu; Shin-Wen Chen; Fang-Tzu Wu; Meng-Shan Lee; Yun-Yi Chen; Wayseen Wang

doi:10.1016/j.tjog.2019.11.024

Cytogenetic discrepancy between cultured amniocytes and uncultured amniocytes in mosaic double trisomy involving trisomy 7 and trisomy 20 (48,XY,+7,+20) at amniocentesis

Taiwan J Obstet Gynecol. 2020 Jan;59(1):146-149. doi: 10.1016/j.tjog.2019.11.024.

Authors

Chih-Ping Chen¹, Yi-Hui Lin², Schu-Rern Chern³, Peih-Shan Wu⁴, Shin-Wen Chen⁵, Fang-Tzu Wu⁵, Meng-Shan Lee⁵, Yun-Yi Chen³, Wayseen Wang⁶

Affiliations

¹ Department of Obstetrics and Gynecology, MacKay Memorial Hospital, Taipei, Taiwan; Department of Medical Research, MacKay Memorial Hospital, Taipei, Taiwan; Department of Biotechnology, Asia University, Taichung, Taiwan; School of Chinese Medicine, College of Chinese Medicine, China Medical University, Taichung, Taiwan; Institute of Clinical and Community Health Nursing, National Yang-Ming University, Taipei, Taiwan; Department of Obstetrics and Gynecology, School of Medicine, National Yang-Ming University, Taipei, Taiwan. Electronic address: cpc_mmh@yahoo.com.
² Department of Obstetrics and Gynecology, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan.
³ Department of Medical Research, MacKay Memorial Hospital, Taipei, Taiwan.
⁴ Gene Biodesign Co. Ltd, Taipei, Taiwan.
⁵ Department of Obstetrics and Gynecology, MacKay Memorial Hospital, Taipei, Taiwan.
⁶ Department of Medical Research, MacKay Memorial Hospital, Taipei, Taiwan; Department of Bioengineering, Tatung University, Taipei, Taiwan.

PMID: 32039784
DOI: 10.1016/j.tjog.2019.11.024

Abstract

Objective: We present mosaic double trisomy involving trisomy 7 and trisomy 20 at amniocentesis in a pregnancy with a favorable outcome.

Case report: A 41-year-old woman underwent amniocentesis at 16 weeks of gestation because of advanced maternal age. Amniocentesis revealed a result of 48,XY,+7,+20[6]/46,XY[26] in cultured amniocytes. At 19 weeks of gestation, repeat amniocentesis was performed, which revealed a result of 48,XY,+7,+20[4]/46,XY[21] in cultured amniocytes. Simultaneous molecular cytogenetic analyses on uncultured amniocytes at repeat amniocentesis revealed no genomic imbalance in array comparative genomic hybridization (aCGH) analysis, no trisomy 7 and no trisomy 20 signals in 114/114 cells in interphase fluorescence in situ hybridization (FISH) analysis, and no uniparental disomy (UPD) 7 and no UPD 20 in quantitative fluorescent polymerase chain reaction (QF-PCR) analysis. Interphase FISH analysis on cultured amniocytes revealed double trisomy of trisomy 7 and trisomy 20 in 5/105 cells (4.7%) compared with 0/100 cells (0%) in the normal control. Prenatal ultrasound findings were unremarkable. The parental karyotypes were normal. The woman decided to continue the pregnancy, and a healthy 2880-g phenotypically normal male baby was delivered at 34 weeks of gestation without any structural abnormality. The cord blood had a normal karyotype. Interphase FISH analysis of the urinary cells revealed no trisomy 7 and no trisomy 20 signals in 51/51 urinary cells.

Conclusion: Cytogenetic discrepancy between cultured amniocytes and uncultured amniocytes can occur in mosaicism for double trisomy involving trisomy 7 and trisomy 20 at amniocentesis. Molecular cytogenetic analyses such as aCGH, FISH and QF-PCR on uncultured amniocytes are useful for rapid distinguishing true mosaicism from pseudomosaicism under such a circumstance.

Keywords: Mosaicism; Trisomy 20; Trisomy 7; UPD 20; UPD 7.

Publication types

Case Reports

MeSH terms

Adult
Amniocentesis / methods*
Amnion / cytology*
Cells, Cultured
Chromosomes, Human, Pair 20 / genetics
Chromosomes, Human, Pair 7*
Female
Humans
Mosaicism
Pregnancy
Trisomy / diagnosis*
Trisomy / genetics

Supplementary concepts

Chromosome 20, trisomy