Risk assessment of assisted reproductive technology and parental age at childbirth for the development of uniparental disomy-mediated imprinting disorders caused by aneuploid gametes.

Background: Our previous study suggested that assisted reproductive technology (ART) may be a possible risk factor for the development of epimutation-mediated imprinting disorders (epi-IDs) for mothers aged ≥ 30 years. However, whether ART or advanced parental age facilitates the development of uniparental disomy-mediated IDs (UPD-IDs) has not yet been investigated.

Results: We enrolled 130 patients with aneuploid UPD-IDs including various IDs confirmed by molecular studies and obtained ART data of the general population and patients with epi-IDs from a robust nationwide database and our previous report, respectively. We compared the proportion of ART-conceived livebirths and maternal childbearing age between patients with UPD-IDs and the general population or patients with epi-IDs. The proportion of ART-conceived livebirths in patients with aneuploid UPD-IDs was consistent with that in the general population of maternal age ≥ 30 years and was lower than that in the patients with epi-IDs, although there was no significant difference. The maternal childbearing age of patients with aneuploid UPD-IDs was skewed to the increased ages with several cases exceeding the 97.5th percentile of maternal childbearing age of the general population and significantly higher than that of patients with epi-IDs (P < 0.001). In addition, we compared the proportion of ART-conceived livebirths and parental age at childbirth between patients with UPD-IDs caused by aneuploid oocytes (oUPD-IDs) and that by aneuploid sperm (sUPD-IDs). Almost all ART-conceived livebirths were identified in patients with oUPD-IDs, and both maternal age and paternal age at childbirth were significantly higher in patients with oUPD-IDs than in patients with sUPD-IDs. Because maternal age and paternal age were strongly correlated (r_s = 0.637, P < 0.001), higher paternal age in oUPD-IDs was explained by the higher maternal age in this group.

Conclusions: Different from the case of epi-IDs, ART itself is not likely to facilitate the development of aneuploid UPD-IDs. We demonstrated that advanced maternal age can be a risk factor for the development of aneuploid UPD-IDs, particularly oUPD-IDs.