Article

G-allele of Intronic rs10830963 in MTNR1B Confers Increased Risk of Impaired Fasting Glycemia and Type 2 Diabetes Through an Impaired Glucose-Stimulated Insulin Release

Steno Diabetes Center, Gentofte, Denmark. .
Diabetes (Impact Factor: 8.47). 04/2009; 58(6):1450-6. DOI: 10.2337/db08-1660
Source: PubMed

ABSTRACT Genome-wide association studies have identified several variants within the MTNR1B locus that are associated with fasting plasma glucose (FPG) and type 2 diabetes. We refined the association signal by direct genotyping and examined for associations of the variant displaying the most independent effect on FPG with isolated impaired fasting glycemia (i-IFG), isolated impaired glucose tolerance (i-IGT), type 2 diabetes, and measures of insulin release and peripheral and hepatic insulin sensitivity.
We examined European-descent participants in the Inter99 study (n = 5,553), in a sample of young healthy Danes (n = 372), in Danish twins (n = 77 elderly and n = 97 young), in additional Danish type 2 diabetic patients (n = 1,626) and control subjects (n = 505), in the Data from the Epidemiological Study on the Insulin Resistance Syndrome (DESIR) study (n = 4,656), in the North Finland Birth Cohort 86 (n = 5,258), and in the Haguenau study (n = 1,461).
The MTNR1B intronic variant, rs10830963, carried most of the effect on FPG and showed the strongest association with FPG (combined P = 5.3 x 10(-31)) and type 2 diabetes. The rs10830963 G-allele increased the risk of i-IFG (odds ratio [OR] 1.64, P = 5.5 x 10(-11)) but not i-IGT. The G-allele was associated with a decreased insulin release after oral and intravenous glucose challenges (P < 0.01) but not after injection of tolbutamide. In elderly twins, the G-allele associated with hepatic insulin resistance (P = 0.017).
The G-allele of MTNR1B rs10830963 increases risk of type 2 diabetes through a state of i-IFG and not through i-IGT. The same allele associates with estimates of beta-cell dysfunction and hepatic insulin resistance.

0 Followers
 · 
119 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Maternal metabolism during pregnancy impacts the developing fetus, affecting offspring birth weight and adiposity. This has important implications for metabolic health later in life (e.g., offspring of mothers with pre-existing or gestational diabetes mellitus have an increased risk of metabolic disorders in childhood). To identify genetic loci associated with measures of maternal metabolism obtained during an oral glucose tolerance test at ∼28 weeks' gestation, we performed a genome-wide association study of 4,437 pregnant mothers of European (n = 1,367), Thai (n = 1,178), Afro-Caribbean (n = 1,075), and Hispanic (n = 817) ancestry, along with replication of top signals in three additional European ancestry cohorts. In addition to identifying associations with genes previously implicated with measures of glucose metabolism in nonpregnant populations, we identified two novel genome-wide significant associations: 2-h plasma glucose and HKDC1, and fasting C-peptide and BACE2. These results suggest that the genetic architecture underlying glucose metabolism may differ, in part, in pregnancy.
    Diabetes 07/2013; 62(10). DOI:10.2337/db12-1692 · 8.47 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Common variants in MTNR1B, encoding melatonin receptor 1B, have been recently associated with impaired glucose homeostasis and an increased risk for developing Type 2 diabetes (T2D). In this study we investigated the association of MTNR1B variant rs10830963 with T2D and related quantitative traits in a population from Bosnia and Herzegovina (BH). A total number of 268 subjects were recruited in the study (162 T2D patients and 106 nondiabetic controls). Subjects were genotyped for MTNR1B rs10830963 SNP by using hydrolysis probes. Our data showed that the prevalence of the MTNR1B rs10830963 risk G-allele in BH population was 26%. Furthermore, we demonstrated a significant association of MTNR1B rs10830963 variant with fasting plasma glucose (FPG) levels in nondiabetic subjects. Under the additive genetic model, each variant G-allele was associated with an increased FPG levels of 0.29 mmol/L (95% CI 0.12, 0.46, p=0.001). Strikingly, our results also showed a significant association of this MTNR1B polymorphism with increased glycated hemoglobin (HbA1c) levels in nondiabetic subjects (p=0.040, additive genetic model). An association of the MTNR1B variant rs10830963 with T2D risk was not detected in our cohort. In conclusion, here we have demonstrated the association between the common MTNR1B rs10830963 variation and fasting plasma glucose levels in BH population. Furthermore, the influence of this polymorphism on the HbA1c levels was also shown in this study, further strengthening its role in blood glucose control.
    Experimental and Clinical Endocrinology & Diabetes 04/2014; 122(6). DOI:10.1055/s-0034-1371871 · 1.76 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Melatonin is synthesized and secreted mainly by the pineal gland in a circadian fashion, and it thus mediates endogenous circadian rhythms and influences other physiological functions. Both the G-protein coupled receptors MT1 (encoded by MTNR1A) and MT2 (encoded by MTNR1B) in mammals mediate the actions of melatonin. Evidence from vivo and vitro studies proved a key role of melatonin in the regulation of glucose metabolism and the pathogenesis of diabetes, as further confirmed by the recent studies of human genetic variants of MTNR1B. Remarkably, it was also suggested that genetic variations within MTNR1B disordered β-cells function directly, i.e. insulin secretion. This indicated the functional link between MT2 and T2D risk at the protein level, and it may represent the prevailing pathomechanism for how impaired melatonin signaling causes metabolic disorders and increases the T2D risk. It is speculated that melatonin and its receptors may be a new therapeutic avenue in diabetes.
    European Journal of Pharmacology 08/2014; 744. DOI:10.1016/j.ejphar.2014.08.012 · 2.68 Impact Factor

Full-text (2 Sources)

Download
13 Downloads
Available from
May 31, 2014

Similar Publications