Rates of unbalanced chromosome rearrangements associated with pericentric and paracentric inversions: Analysis of molecular chromosome results in embryo samples

To evaluate the outcomes of preimplantation genetic testing for structural rearrangements for individuals with pericentric or paracentric inversions undergoing in vitro fertilization.

This retrospective study included trophectoderm (TE) embryo biopsy samples analyzed at a single reference laboratory from 37 reproductive couples who underwent 44 in vitro fertilization cycles. TE biopsies and parental samples were genotyped using Illumina CytoSNP-12b microarrays with bioinformatic analysis to determine the parental origin of each chromosome.

For 137 TE biopsy samples with results from 24 individuals with pericentric inversions, the frequency of deletions and duplications related to the inversion was analyzed based on the relative size of the inverted segment. We observed a rate of 5% inversion-associated deletions and duplications for samples from individuals with inversions <30% of the chromosome, 3% from inversions 30% to 50% of the chromosome, and 21% from inversions >50% of the chromosome. Of 43 TE biopsy samples from 7 individuals with paracentric inversions, 2% had inversion-associated deletions and duplications, and 7% had monosomy related to the parental inversion, all of which were from 1 individual.

Although previously considered to have minimal reproductive impact, we identified inversion-associated abnormalities in TE biopsy samples from individuals with paracentric and small pericentric inversions, underscoring a small but meaningful reproductive risk associated with these rearrangements.