Vella M, Mohan S, Christie H, Bailey KR, Cobelli C, Dalla Man C, Matveyenko A, Egan AM, Vella A. Diabetes-associated Genetic Variation in
MTNR1B and Its Effect on Islet Function.
J Endocr Soc 2024;
8:bvae130. [PMID:
39011323 PMCID:
PMC11249077 DOI:
10.1210/jendso/bvae130]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2024] [Indexed: 07/17/2024] Open
Abstract
Context
Multiple common genetic variants have been associated with type 2 diabetes, but the mechanism by which they predispose to diabetes is incompletely understood. One such example is variation in MTNR1B, which implicates melatonin and its receptor in the pathogenesis of type 2 diabetes.
Objective
To characterize the effect of diabetes-associated genetic variation at rs10830963 in the MTNR1B locus on islet function in people without type 2 diabetes.
Design
The association of genetic variation at rs10830963 with glucose, insulin, C-peptide, glucagon, and indices of insulin secretion and action were tested in a cohort of 294 individuals who had previously undergone an oral glucose tolerance test (OGTT). Insulin sensitivity, β-cell responsivity to glucose, and Disposition Indices were measured using the oral minimal model.
Setting
The Clinical Research and Translation Unit at Mayo Clinic, Rochester, MN.
Participants
Two cohorts were utilized for this analysis: 1 cohort was recruited on the basis of prior participation in a population-based study in Olmsted County. The other cohort was recruited on the basis of TCF7L2 genotype at rs7903146 from the Mayo Biobank.
Intervention
Two-hour, 7-sample OGTT.
Main Outcome Measures
Fasting, nadir, and integrated glucagon concentrations.
Results
One or 2 copies of the G-allele at rs10830963 were associated with increased postchallenge glucose and glucagon concentrations compared to subjects with the CC genotype.
Conclusion
The effects of rs10830963 on glucose homeostasis and predisposition to type 2 diabetes are likely to be partially mediated through changes in α-cell function.
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