Background: Genetic determinants of glycemic regulation in pregnancy are poorly understood.

Methods: We studied 35 glycemia-related traits measured during pregnancy and 191 genetic variants identified in prior genome-wide association studies of type 2 diabetes (T2D) or gestational glycemia. Using linear regression, we quantified associations between glucose-raising alleles and traits measured in 582 women at 24-28 weeks gestation. We clustered traits and variants using Bayesian nonnegative matrix factorization (bNMF) to identify physiologic pathways involved in pregnancy glucose metabolism.

Results: In a plurality of bNMF iterations (22/50), 5 clusters emerged, with highly weighted traits and loci suggesting distinct physiologic pathways. Cluster 1: reduced insulin secretory response (lower insulin/c-peptide, greater insulin sensitivity); loci included several known or suspected to affect beta-cell function (ABO, CDKN2B, SLC30A8, CDKN1B). Cluster 2: obesity-related hyperglycemia (higher percent body fat, BMI, fasting/post-load glucose); loci included known obesity/T2D loci (MCR4, FTO) and loci previously tied to beta-cell function that associated with higher glucose and greater adiposity pregnant women (MTNR1B, GLP2R). Cluster 3: insulin resistance (reduced insulin sensitivity, higher fasting insulin/c-peptide, greater insulin secretory response); loci included LYPLAL1 and ANKRD55 (known to harbor insulin resistance variants). Cluster 4 traits suggested reduced adiposity with post-load glucose intolerance. Cluster 5 traits suggested a favorable metabolic profile (lower cholesterol and glucose, higher disposition index and insulin sensitivity).

Conclusion: Genetic variants can be grouped to identify physiologic mechanisms at play in gestational glycemic regulation. Associations between physiologically-informed variant clusters, gestational diabetes, and related perinatal outcomes await testing in well-powered cohorts.

Disclosure

C.E. Powe: None. M. Udler: None. C. Allard: None. J. Kim: None. P. Perron: None. L. Bouchard: None. J.C. Florez: None. M. Hivert: None.

Funding

American Diabetes Association/Pathway to Stop Diabetes (1-15-ACE-26 to M-F.H.); National Institute of Diabetes and Digestive and Kidney Diseases (K23DK113218, K24DK110550); Robert Wood Johnson Foundation; Fonds de la recherche du Québec en santé

© 2019 by the American Diabetes Association.
2019
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