Pericentric inversion (Inv) 9 variant-reproductive risk factor or benign finding?

To report the unbalanced chromosome rearrangement rate and overall aneuploidy rate in day 5/6 embryos from a series of patients who underwent in vitro fertilization (IVF) with preimplantation genetic testing for structural rearrangements (PGT-SR) for the pericentric inversion 9 variant, inv(9)(p11q13) or inv(9)(p12q13), with concurrent 24 chromosome preimplantation genetic testing for aneuploidy (PGT-A).

This was a retrospective cohort analysis. IVF cycles and embryo biopsies were performed by referring clinics. Fifty-two trophectoderm biopsy samples from seven couples were sent to a single lab for PGT-SR for an inversion 9 variant with concurrent 24 chromosome PGT-A using single-nucleotide polymorphism (SNP) microarrays with bioinformatics.

The unbalanced rearrangement rate for this embryo cohort was 0/52 (0.0%); mean maternal age per embryo was 33.3 years (range 21-39 years). The overall euploid rate was 61.5% and aneuploidy rate was 38.5%.

Chromosome 9 pericentric inversions did not result in unbalanced structural rearrangements in day 5/6 embryo samples, supporting that this population variant is not associated with increased reproductive risks.