Mosaic embryo transfer-first report of a live born with nonmosaic partial aneuploidy and uniparental disomy 15

Kamilla Schlade-Bartusiak; Emma Strong; Olive Zhu; Jessica Mackie; Diane Salema; Michael Volodarsky; Jeffrey Roberts; Michelle Steinraths

doi:10.1016/j.xfre.2022.05.003

Mosaic embryo transfer-first report of a live born with nonmosaic partial aneuploidy and uniparental disomy 15

F S Rep. 2022 May 10;3(3):192-197. doi: 10.1016/j.xfre.2022.05.003. eCollection 2022 Sep.

Authors

Kamilla Schlade-Bartusiak^{1

2}, Emma Strong^{1

2}, Olive Zhu³, Jessica Mackie³, Diane Salema³, Michael Volodarsky¹, Jeffrey Roberts³, Michelle Steinraths⁴

Affiliations

¹ Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada.
² BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada.
³ Pacific Center for Reproductive Medicine, Burnaby, British Columbia, Canada.
⁴ Department of Medical Genetics, University of British Columbia, Victoria, British Columbia, Canada.

Abstract

Objective: To inform clinicians of the first known case of a live born diagnosed with syndromic partial trisomy 15 and maternal uniparental disomy 15 resulting from a mosaic embryo transfer (MET). We believe that this case will highlight the need for standardized practice guidelines to address the potential risk of MET and the importance of prenatal follow-up after a pregnancy is achieved from a MET.

Design: Case report.

Setting: In vitro fertilization with preimplantation genetic testing for aneuploidy (PGT-A) and MET was completed at a fertility clinic in Canada. Postnatal testing and diagnosis were performed at the Medical Genetics Department of a hospital in Canada.

Patients: A newborn male with a diagnosis of partial trisomy 15 and uniparental disomy (UPD) 15.

Interventions: Mosaic embryo transfer after PGT-A was performed. Diagnostic testing performed after birth included a karyotype, fluorescence in situ hybridization analysis, chromosomal microarray, and microsatellite UPD testing.

Main outcome measures: Confirmed nonmosaic partial aneuploidy of trisomy 15 and UPD15 in a symptomatic newborn conceived from MET.

Results: Singleton pregnancy was achieved after a double embryo transfer involving 1 embryo diagnosed by PGT-A with high-level mosaic trisomy 15 and high-level mosaic deletion on chromosome 20 (mos(del(20)(q11.23-qter)). Routine prenatal screening and detailed fetal ultrasound did not identify any concerns. Postnatal genetic investigations, triggered by feeding difficulties in the newborn period, diagnosed the proband with maternal UPD15 and a supernumerary marker chromosome composed of 2 noncontiguous regions of chromosome 15. This karyotype is likely resulting from incomplete trisomy rescue occurring on the paternal chromosome 15.

Conclusions: This case highlights the need for better guidelines and management of pregnancies achieved after MET.

Keywords: PGT-A; aneuploidy; mosaic embryo transfer; trisomy 15; trisomy rescue; uniparental disomy 15.