A CASE REPORT OF PRENATAL-CONFIRMED TRISOMY 7 MOSAICISM AFTER COMPLEX MOSAIC EMBRYO
Main Article Content
Abstract
Preimplantation genetic testing for aneuploidy (PGT-A) has been increasingly widely used in assisted reproductive technology, particularly in patients with a history of recurrent pregnancy loss or repeated implantation failure. The development of next-generation sequencing (NGS) technology has increased the detection rate of mosaic embryos, posing many challenges in embryo transfer decision-making and subsequent pregnancy management [1–4].
Although many studies and case reports have demonstrated the possibility of achieving a healthy live birth after mosaic embryo transfer, the risks of persistent fetal mosaicism, confined placental mosaicism, and discordance among preimplantation genetic testing, prenatal diagnosis, and postnatal testing remain not fully clarified [2,5,6]. Therefore, case reports with comprehensive pre- and postnatal follow-up play an important role in providing real-world evidence for clinical practice.
We report the case of a 32-year-old woman with infertility due to bilateral tubal obstruction and a history of recurrent pregnancy loss. Following one in vitro fertilization cycle combined with PGT-A, no euploid embryos were identified; only one complex mosaic embryo was available. After comprehensive genetic counseling, the patient elected to proceed with mosaic embryo transfer. Pregnancy was achieved after frozen–thawed embryo transfer. Prenatal diagnosis by amniocentesis confirmed mosaic trisomy 7 (20%). Serial fetal morphological assessments revealed no structural abnormalities. The infant was delivered preterm at 34 weeks and 5 days of gestation, with a birth weight appropriate for gestational age, and postnatal peripheral blood karyotype analysis showed no chromosomal abnormalities.
Article Details
Keywords
mosaic embryo, PGT-A, trisomy 7, amniocentesis, genetic counseling.
References
2. Spinella F, Fiorentino F, Biricik A, et al. Extent of chromosomal mosaicism influences the clinical outcome of in vitro fertilization treatments. Fertil Steril. 2018;109(1):77–83.
3. Viotti M. Preimplantation genetic testing for chromosomal abnormalities: Aneuploidy, mosaicism, and structural rearrangements. Genes. 2020;11(6):602.
4. Cram DS, Leigh D, Handyside A, et al. PGDIS position statement on the transfer of mosaic embryos 2019. Reprod Biomed Online. 2019;39(4):e1–e4.
5. Grati FR, Malvestiti F, Ferreira JCPB, et al. Fetoplacental mosaicism: Potential implications for false-positive and false-negative noninvasive prenatal screening results. Genet Med. 2014;16(8):620–624.
6. Grati FR, Gallazzi G, Branca L, et al. An evidence-based scoring system for prioritizing mosaic embryos following preimplantation genetic screening. Reprod Biomed Online. 2018;36(4):442–449.
7. Sifakis S, Kalykakis K, Koukoura O, et al. Prenatal diagnosis of trisomy 7 mosaicism: A case report and review of the literature. Prenat Diagn. 2004;24(6):462–465.
8. Chen CP, Chang TY, Wang LK, et al. Prenatal diagnosis of trisomy 7 mosaicism and literature review. Taiwan J Obstet Gynecol. 2012;51(3):452–456.
9. Tug N, Balat O, Yilmaz M, et al. Prenatal diagnosis of trisomy 7 mosaicism with normal fetal outcome. J Obstet Gynaecol Res. 2017;43(6):1104–1108.
10. Fisch GS, Shprintzen RJ, et al. Chromosome 7 abnormalities and developmental outcomes: A review. Am J Med Genet A. 2016;170(6):1433–1444.
11. Taylor TH, Gitlin SA, Patrick JL, et al. The origin, mechanisms, incidence and clinical consequences of chromosomal mosaicism in humans. Hum Reprod Update. 2014;20(4):571–581.
12. McCoy RC. Mosaicism in preimplantation human embryos: When chromosomal abnormalities are the norm. Trends Genet. 2017;33(7):448–463.