Leptin receptor gene variation predicts weight change in subjects with impaired glucose tolerance.

The leptin receptor (OB-R) gene is a promising candidate gene for type 2 diabetes, because leptin and its receptor play an important role in insulin secretion and the development of obesity. Therefore, we studied whether the pentanucleotide insertion polymorphism of the 3'-untranslated region (3'UTR) of the OB-R gene has an influence on the conversion from impaired glucose tolerance (IGT) to type 2 diabetes in the STOP-Noninsulin-Dependent Diabetes Mellitus trial. The STOP trial was a longitudinal, double-blind, placebo-controlled randomized trial that included 1429 subjects with IGT from high-risk populations. Using the restriction fragment length polymorphism method, we genotyped 770 subjects whose DNA was available for the insertion/deletion polymorphism of the 3'UTR of the OB-R gene. We did not find a relationship between the OB-R polymorphism and the conversion from IGT to type 2 diabetes (p = 0.747). However, the insertion allele was associated with a significant reduction in weight (p = 0.016), BMI (p = 0.009), and waist circumference (p = 0.006) in all subjects. Women carrying the I allele had a larger waist circumference change (p = 0.036), whereas men lost more weight and had a greater decrease in BMI. The pentanucleotide insertion/deletion polymorphism in the 3'UTR of the OB-R gene did not influence the conversion to type 2 diabetes in obese patients with IGT. However, this polymorphism was associated with a significant weight change, suggesting that it may potentially modulate the risk for type 2 diabetes.

Association of adiponectin level and variants in the adiponectin gene with glucose metabolism, energy expenditure, and cytokines in offspring of type 2 diabetic patients.

OBJECTIVE: Adiponectin is an adipose-specific secretory protein abundantly present in the circulation. The role of adiponectin in the control of energy expenditure and substrate utilization has not yet been established. DESIGN: We performed detailed metabolic studies in a large cohort (n = 158) of offspring of patients with type 2 diabetes (T2DM) to determine the association of adiponectin level with glucose and lipid oxidation, energy expenditure, insulin sensitivity, and visceral obesity by applying the euglycemic clamp technique and indirect calorimetry. RESULTS: The adiponectin level was lower in offspring of T2DM patients than in control subjects. When the data were analyzed by adiponectin tertiles, an elevated adiponectin level was associated with high total, oxidative, and nonoxidative glucose disposal and high energy expenditure during hyperinsulinemia; low levels of free fatty acids and low rates of lipid oxidation during hyperinsulinemia; as well as low levels of inflammatory cytokines; and a low amount of intraabdominal fat evaluated by computed tomography. No association of single nucleotide polymorphism 45 or single nucleotide polymorphism 276 with adiponectin level was found. CONCLUSIONS: We conclude that adiponectin has multiple effects on glucose, lipid and free fatty acid metabolism, and cytokines in offspring of T2DM subjects.

The common polymorphisms (single nucleotide polymorphism [SNP] +45 and SNP +276) of the adiponectin gene predict the conversion from impaired glucose tolerance to type 2 diabetes: the STOP-NIDDM trial.

Adiponectin is an adipose tissue-specific protein with insulin-sensitizing and antiatherogenic properties. Therefore, the adiponectin gene is a promising candidate gene for type 2 diabetes. We investigated the single nucleotide polymorphisms (SNPs) +45T/G and +276G/T of the adiponectin gene as predictors for the conversion from impaired glucose tolerance to type 2 diabetes in the STOP-NIDDM trial, which aimed to investigate the effect of acarbose compared with placebo on the prevention of type 2 diabetes. Compared with the TT genotype, the G-allele of SNP +45 was associated with a 1.8-fold risk for type 2 diabetes (95% CI 1.12-3.00, P = 0.015) in the placebo group. Subjects treated with placebo and simultaneously having the G-allele of SNP +45 and the T-allele of SNP +276 (the risk genotype combination) had a 4.5-fold (1.78-11.3, P = 0.001) higher risk of developing type 2 diabetes compared with subjects carrying neither of these alleles. Women carrying the risk genotype combination had an especially high risk of conversion to diabetes (odds ratio 22.2, 95% CI 2.7-183.3, P = 0.004). In conclusion, the G-allele of SNP +45 is a predictor for the conversion to type 2 diabetes. Furthermore, the combined effect of SNP +45 and SNP +276 on the development of type 2 diabetes was stronger than that of each SNP alone.