Association Testing of Novel Type 2 Diabetes Risk Alleles in the JAZF1, CDC123/CAMK1D, TSPAN8, THADA, ADAMTS9, and NOTCH2 Loci With Insulin Release, Insulin Sensitivity, and Obesity in a Population-Based Sample of 4,516 Glucose-Tolerant Middle-Aged Danes

  1. Niels Grarup1,
  2. Gitte Andersen1,
  3. Nikolaj T. Krarup1,
  4. Anders Albrechtsen2,
  5. Ole Schmitz34,
  6. Torben Jørgensen5,
  7. Knut Borch-Johnsen156,
  8. Torben Hansen1 and
  9. Oluf Pedersen16
  1. 1Steno Diabetes Center, Copenhagen, Denmark
  2. 2Department of Biostatistics, University of Copenhagen, Copenhagen, Denmark
  3. 3Department of Endocrinology and Diabetes, Aarhus University Hospital, Aarhus, Denmark
  4. 4Department of Clinical Pharmacology, University of Aarhus, Aarhus, Denmark
  5. 5Research Centre for Prevention and Health, Glostrup University Hospital, Glostrup, Denmark
  6. 6Faculty of Health Sciences, University of Aarhus, Aarhus, Denmark
  1. Corresponding author: Niels Grarup, ngrp{at}steno.dk

Abstract

OBJECTIVE— We evaluated the impact on diabetes-related intermediary traits of common novel type 2 diabetes–associated variants in the JAZF1 (rs864745), CDC123/CAMK1D (rs12779790), TSPAN8 (rs7961581), THADA (rs7578597), ADAMTS9 (rs4607103), and NOTCH2 (rs10923931) loci, which were recently identified by meta-analysis of genome-wide association data.

RESEARCH DESIGN AND METHODS— We genotyped the six variants in 4,516 middle-aged glucose-tolerant individuals of the population-based Inter99 cohort who were all characterized by an oral glucose tolerance test (OGTT).

RESULTS— Homozygous carriers of the minor diabetes risk G-allele of the CDC123/CAMK1D rs12779790 showed an 18% decrease in insulinogenic index (95% CI 10–27%; P = 4 × 10−5), an 18% decrease in corrected insulin response (CIR) (8.1–29%; P = 4 × 10−4), and a 13% decrease in the ratio of area under the serum-insulin and plasma-glucose curves during an OGTT (AUC-insulin/AUC-glucose) (5.8–20%; P = 4 × 10−4). Carriers of the diabetes-associated T-allele of JAZF1 rs864745 had an allele-dependent 3% decrease in BIGTT-AIR (0.9–4.3%; P = 0.003). Furthermore, the diabetes-associated C-allele of TSPAN8 rs7961581 associated with decreased levels of CIR (4.5% [0.5–8.4]; P = 0.03), of AUC-insulin/AUC-glucose ratio (3.9% [1.2–6.7]; P = 0.005), and of the insulinogenic index (5.2% [1.9–8.6]; P = 0.002). No association with traits of insulin release or insulin action was observed for the THADA, ADAMTS9, or NOTCH2 variants.

CONCLUSIONS— If replicated, our data suggest that type 2 diabetes at-risk alleles in the JAZF1, CDC123/CAMK1D, and TSPAN8 loci associate with various OGTT-based surrogate measures of insulin release, emphasizing the contribution of abnormal pancreatic β-cell function in the pathogenesis of type 2 diabetes.

Footnotes

  • Published ahead of print at http://diabetes.diabetesjournals.org on 20 June 2008.

    Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered. See http://creativecommons.org/licenses/by-nc-nd/3.0/ for details.

    The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

    • Accepted June 16, 2008.
    • Received March 30, 2008.
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  1. Diabetes vol. 57 no. 9 2534-2540
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