Overview
- A Nature study led by Johns Hopkins researchers analyzed genetic data from 139,416 IVF embryos and roughly 23,000 parents, finding aneuploidy in about 30% of embryos.
- Four maternal variants in SMC1B, C14orf39, CCNB1IP1, and RNF212 were associated with increased rates of meiotic or recombination-related chromosome errors.
- The SMC1B rs2272804 A allele, linked to reduced SMC1B expression and higher aneuploidy risk, is present in about 44% of people globally and about 71% of Africans; risk alleles in the three recombination genes occur at roughly 39%, 42%, and 22% worldwide.
- Aneuploid embryos exhibited fewer crossover recombination events, with 57,974 trisomies and 34,511 monosomies observed, most frequently involving chromosomes 5, 16, 21, and 22.
- Researchers emphasize that maternal age remains the dominant driver of risk and that these common variants currently offer limited value for individual clinical prediction, though they highlight key biological pathways for future research.