Prenatal diagnosis and molecular genetic analysis of recurrent trisomy 18 of maternal origin in two consecutive pregnancies

• Main Authors: Chih-Ping Chen (Author), Fang-Tzu Wu (Author), Chian-Huey Wong (Author), Shin-Wen Chen (Author), Schu-Rern Chern (Author), Yen-Ting Pan (Author), Wen-Lin Chen (Author), Wayseen Wang (Author)
• Format: Book
• Published: Elsevier, 2023-05-01T00:00:00Z.
• Subjects: article
• Online Access: Connect to this object online.
• Notes: 1028-4559; 10.1016/j.tjog.2023.03.006
• Keywords: NIPT (non-invasive prenatal testing); Maternal origin; Recurrence; Trisomy 18; Gynecology and obstetrics; RG1-991
• Source: Taiwanese Journal of Obstetrics & Gynecology, Vol 62, Iss 3, Pp 444-447 (2023)

Objective: We present prenatal diagnosis and molecular genetic analysis of recurrent trisomy 18 of maternal origin in two consecutive pregnancies. Case report: A 37-year-old, gravida 3, para 1, woman was referred for genetic counseling because of cystic hygroma on ultrasound at 12 weeks of gestation, a previous pregnancy with a fetus with trisomy 18, and an abnormal first-trimester non-invasive prenatal testing (NIPT) result of Z score of 9.74 (normal: −3.0-3.0) in chromosome 18 suggesting trisomy 18 during this pregnancy. The fetus died at 14 weeks of gestation, and a malformed fetus was terminated at 15 weeks of gestation. Cytogenetic analysis of the placenta revealed a karyotype of 47,XY,+18. Quantitative fluorescent polymerase chain reaction (QF-PCR) assays on the DNA extracted from parental bloods and umbilical cord determined a maternal origin of trisomy 18. One year previously, the woman underwent amniocentesis at 17 weeks of gestation because of advanced maternal age of 36 years. Amniocentesis revealed a karyotype of 47,XX,+18. Prenatal ultrasound was unremarkable. The mother had a karyotype of 46,XX, and the father had a karyotype of 46,XY. QF-PCR assays on the DNA extracted from parental bloods and cultured amniocytes determined a maternal origin of trisomy 18. The pregnancy was subsequently terminated. Conclusion: NIPT is useful for rapid prenatal diagnosis of recurrent trisomy 18 under such a circumstance.