Human Genomics (Jul 2024)
Genetic distance and ancestry proportion modify the association between maternal genetic risk score of type 2 diabetes and fetal growth
Abstract
Abstract Background Maternal genetic risk of type 2 diabetes (T2D) has been associated with fetal growth, but the influence of genetic ancestry is not yet fully understood. We aimed to investigate the influence of genetic distance (GD) and genetic ancestry proportion (GAP) on the association of maternal genetic risk score of T2D (GRST2D) with fetal weight and birthweight. Methods Multi-ancestral pregnant women (n = 1,837) from the NICHD Fetal Growth Studies – Singletons cohort were included in the current analyses. Fetal weight (in grams, g) was estimated from ultrasound measurements of fetal biometry, and birthweight (g) was measured at delivery. GRS T2D was calculated using T2D-associated variants identified in the latest trans-ancestral genome-wide association study and was categorized into quartiles. GD and GAP were estimated using genotype data of four reference populations. GD was categorized into closest, middle, and farthest tertiles, and GAP was categorized as highest, medium, and lowest. Linear regression analyses were performed to test the association of GRST2D with fetal weight and birthweight, adjusted for covariates, in each GD and GAP category. Results Among women with the closest GD from African and Amerindigenous ancestries, the fourth and third GRS T2D quartile was significantly associated with 5.18 to 7.48 g (weeks 17–20) and 6.83 to 25.44 g (weeks 19–27) larger fetal weight compared to the first quartile, respectively. Among women with middle GD from European ancestry, the fourth GRS T2D quartile was significantly associated with 5.73 to 21.21 g (weeks 18–26) larger fetal weight. Furthermore, among women with middle GD from European and African ancestries, the fourth and second GRS T2D quartiles were significantly associated with 117.04 g (95% CI = 23.88–210.20, p = 0.014) and 95.05 g (95% CI = 4.73–185.36, p = 0.039) larger birthweight compared to the first quartile, respectively. The absence of significant association among women with the closest GD from East Asian ancestry was complemented by a positive significant association among women with the highest East Asian GAP. Conclusions The association between maternal GRS T2D and fetal growth began in early-second trimester and was influenced by GD and GAP. The results suggest the use of genetic GD and GAP could improve the generalizability of GRS.
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