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The Common P446L Polymorphism in GCKR Inversely Modulates Fasting Glucose and Triglyceride Levels and Reduces Type 2 Diabetes Risk in the DESIR Prospective General French Population

  1. Martine Vaxillaire12,
  2. Christine Cavalcanti-Proença12,
  3. Aurélie Dechaume12,
  4. Jean Tichet3,
  5. Michel Marre456,
  6. Beverley Balkau78,
  7. Philippe Froguel129 and
  8. for the DESIR Study Group
  1. 1CNRS 8090–Institute of Biology, Pasteur Institute, Lille, France
  2. 2Lille 2 University, Lille, France
  3. 3Regional Institut for Health, Tours, France
  4. 4INSERM U695, Paris, France
  5. 5René Diderot-Paris 7 University, Paris, France
  6. 6Department of Endocrinology–Diabetology and Nutrition, Bichat Claude Bernard Hospital, Paris, France
  7. 7INSERM U780-IFR69, Villejuif, France
  8. 8University of Paris-Sud, Villejuif, France
  9. 9Section of Genomic Medicine, Hammersmith Hospital, Imperial College London, U.K
  1. Corresponding author: Dr. Martine Vaxillaire, martine.vaxillaire{at}good.ibl.fr

Abstract

OBJECTIVE— Hepatic glucokinase (GCK) is a key regulator of glucose storage and disposal in the liver, where its activity is competitively modulated, with respect to glucose, by binding to glucokinase regulatory protein (GCKR) in the presence of fructose 6-phosphate. Genome-wide association studies for type 2 diabetes identified GCKR as a potential locus for modulating triglyceride levels. We evaluated, in a general French population, the contribution of the GCKR rs1260326-P446L polymorphism to quantitative metabolic parameters and to dyslipidemia and hyperglycemia risk.

RESEARCH DESIGN AND METHODS— Genotype effects of rs1260326 were studied in 4,833 participants from the prospective DESIR (Data from an Epidemiological Study on the Insulin Resistance syndrome) cohort both at inclusion and using the measurements at follow-up.

RESULTS— The minor T-allele of rs1260326 was strongly associated with lower fasting glucose (−1.43% per T-allele; P = 8 × 10−13) and fasting insulin levels (−4.23%; P = 3 × 10−7), lower homeostasis model assessment of insulin resistance index (−5.69%; P = 1 × 10−8), and, conversely, higher triglyceride levels (3.41%; P = 1 × 10−4) during the 9-year study. These effects relate to a lower risk of hyperglycemia (odds ratio [OR] 0.79 [95% CI 0.70–0.88]; P = 4 × 10−5) and of incident cases during the study (hazard ratio [HR] 0.83 [0.74–0.95]; P = 0.005). Moreover, an additive effect of GCKR rs1260326(T) and GCK (−30G) alleles conferred lower fasting glycemia (P = 1 × 10−13), insulinemia (P = 5 × 10−6), and hyperglycemia risk (P = 1 × 10−6).

CONCLUSIONS— GCKR-L446 carriers are protected against type 2 diabetes despite higher triglyceride levels and risk of dyslipidemia, which suggests a potential molecular mechanism by which these two components of the metabolic syndrome can be dissociated.

Footnotes

  • Published ahead of print at http://diabetes.diabetesjournals.org on 12 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 May 19, 2008.
    • Received December 21, 2007.
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