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

Area of Science:

• Reproductive Genetics
• Human Genetics
• Cytogenetics

Background:

• The pericentric inversion of chromosome 9, specifically inv(9)(p11q13) or inv(9)(p12q13), is a common population variant.
• Its clinical significance regarding reproductive outcomes remains debated.
• Preimplantation genetic testing offers a window into embryonic chromosomal health.

Purpose of the Study:

• To determine the rate of unbalanced chromosome rearrangements in embryos from patients with the inv(9) variant.
• To assess the overall aneuploidy rate in these embryos concurrently with PGT-SR.
• To evaluate the reproductive risk associated with the inv(9) variant.

Main Methods:

• Retrospective cohort analysis of 52 trophectoderm biopsy samples from seven couples undergoing IVF.
• Concurrent preimplantation genetic testing for structural rearrangements (PGT-SR) for inv(9) and 24-chromosome preimplantation genetic testing for aneuploidy (PGT-A).
• Analysis using single-nucleotide polymorphism (SNP) microarrays and bioinformatics.

Main Results:

• No unbalanced rearrangements (0.0%) were detected in the 52 embryos analyzed.
• The overall euploid rate was 61.5%, with an aneuploidy rate of 38.5%.
• Mean maternal age was 33.3 years (range 21-39 years).

Conclusions:

• The inv(9) variant was not associated with an increased rate of unbalanced structural rearrangements in day 5/6 embryos.
• This common population variant does not appear to pose a significant reproductive risk.
• Findings support the safety of PGT-SR and PGT-A in patients with inv(9).