Adiponectin Is Associated With Type 2 Diabetes,

AIMS: To investigate the genotype distribution of adiponectin +45nucleotide T/G polymorphism and study the relationship of thepolymorphism to insulin resistance and risk of type 2 diabetes in pedigreesof type 2 diabetes. METHODS: The study included 333 subjects: 122 unrelated type 2diabetics and 108 unrelated, non-diabetic first-degree relatives selectedfrom type 2 diabetic pedigrees, and 103 healthy subjects with normalglucose-tolerance serving as controls. All subjects were genotyped for thepolymorphism of adiponectin by PCR-RFLP assay. Plasma glucose, lipids and insulin were determined. Body mass index (BMI) and insulinresistance index (HOMA-IR) were evaluated. RESULTS: 1. The TT, TG and GG genotype frequencies ofadiponenctin +45 nucleotide T/G polymorphism in Chinese populationwere 49.85%, 44.4% and 5.71%,respectively. The observed genotypefrequencies were in Hardy-Weinberg equilibrium. The allelic frequencieswere 72.07 % for A allele and 27 .93% for G allele. 2. The frequency ofGG genotype in type 2 diabetic group was higher than that in non-diabeticfirst-degree relatives and in normal controls. The frequencies of TT and TGgenotype in type 2 diabetic group were the same as those in non-diabeticfirst-degree relatives and in normal controls. The frequency of G allele intype 2 diabetic group was higher than that in non-diabetic first-degreerelatives and in normal controls. The frequency of T allele in type 2diabetic group was lower than that in non-diabetic first-degree relatives andin normal controls. The genotype and allelic frequencies in non-diabeticfirst-degree relatives group were the same as those in control group. 3. TheBMI of TG+GG genotypes in the type 2 diabetic group and in non-diabeticfirst-degree relatives group was higher than that of TT genotype. The BMIof each genotype in normal controls had no significant difference. Thefrequencies of TG+GG genotypes and G allele in BMI≥25 subgroup ofthe type 2 diabetic group and non-diabetic first-degree relatives group were higher than those in BMI〈25 subgroup. 4. The HOMA-IR of TG+GGgenotypes in non-diabetic first-degree relatives group was higher than thatof TT genotype, which was still significant after correction with BMI. TheHOMA-IR of each genotype in normal controls had no significantdifference. 5. Stepwise regression showed that the HOMA-IR in non-diabetic first-degree relatives group was correlated with FINS,FPG,BMIand genotype, which was still significant after correction with BMI. TheHOMA-IR in normal controls had no correlation with genotype. CONCLUTION: The polymorphism of adiponectin +45 nucleotideT/G polymorphism was associated with obesity and insulin resistance, andthe adiponectin gene maybe a new susceptibility gene to type 2 diabetes.