Aims/hypothesis: The cytokine interleukin 6 (IL-6) is an essential regulator of the acute phase response associated with insulin-resistant states including type 2 diabetes and obesity. Three polymorphisms at positions −597, −572, and −174 of the IL6 promoter have been reported to influence IL6 transcription. The aim of this study was to investigate whether the IL6 promoter polymorphisms were associated with features of the WHOdefined metabolic syndrome and related quantitative traits in 7,553 Caucasian Danes. Methods: Using analysis of PCR-generated primer extension products by mass spectrometry we examined −597 G/A, −572 G/C, and −174 G/ C IL6 variants in the population-based Inter99 study cohort of middle-aged people (n=6,164) and in a group of type 2 diabetic patients (n=1,389). Results: The −174 G/C and −597 G/A polymorphisms were in strong linkage disequilibrium (R 2 =0.95). In the Inter99 cohort the −174 G-allele was associated with insulin resistance (p<0.02) and dyslipidaemia (p<0.007) whereas the C-allele of the −572 polymorphism was associated with increased serum insulin release during an OGTT (p<0.0005). Composite genotype or haplotype analyses of all 3 IL6 promoter variants showed associations with type 2 diabetes (p<0.002), obesity (p<0.02), and the metabolic syndrome (p<0.01). Conclusions:The present studies suggest that single-nucleotide polymorphisms and composite genotypes or haplotypes of the IL6 promoter may be associated with several features of the metabolic syndrome in Caucasians.

A graded relationship has been reported between fasting and postprandial plasma glucose levels and the subsequent risk of cardiovascular morbidity and mortality. We hypothesized that the GCK ؊30G>A promoter polymorphism is associated with elevated glycemia in the middle-aged general population of whites, as well as with features of the World Health Organization (WHO)-defined metabolic syndrome. The GCK ؊30G>A polymorphism was genotyped in the population-based Inter99 study cohort (5,965 subjects) and in 332 nondiabetic subjects and 1,063 patients with type 2 diabetes. In the Inter99 cohort, the GCK ؊30A allele was associated with increased fasting (P < 0.001) and post-oral glucose tolerance test (OGTT) plasma glucose levels (P < 0.001), and in the same cohort, the GCK ؊30A allele was more frequent among 1,325 subjects with the metabolic syndrome than among 1,679 subjects without any components of the metabolic syndrome (P ‫؍‬ 0.002). Moreover, the GCK ؊30A allele frequency was higher among 2,587 subjects with impaired glucose regulation (IGR) than among 4,773 glucose-tolerant subjects (

Aims/hypothesis: The hepatocyte nuclear factor (HNF)-4α is an orphan nuclear receptor, which plays crucial roles in regulating hepatic gluconeogenesis and insulin secretion. The gene encoding HNF-4α (HNF4A) is located on chromosome 20q12-q13 in a region that in several studies has shown linkage with type 2 diabetes. Recently, two independent studies identified single nucleotide polymorphisms (SNPs) in a 90-kb region spanning HNF4A, which showed strong association with type 2 diabetes in the Finnish and Ashkenazi Jewish populations. In an attempt to replicate and extend these findings, we selected four SNPs in the same HNF4A region, which in the Finnish and Ashkenazi Jewish populations were associated with type 2 diabetes, and examined their relationships with type 2 diabetes and prediabetic phenotypes in the Danish Caucasian population. Methods: The rs1884614, rs2425637, rs1885088 and rs3818247 were analysed in case-control studies of 1387, 1429, 1417 and 1371 type 2 diabetic patients and 4766, 4727, 4665 and 4748 glucose-tolerant subjects respectively. Genotype-quantitative trait analyses comprised 4430, 4394, 4336 and 4413 middle-aged glucose-tolerant subjects from the population-based Inter99 cohort for the rs1884614, rs2425637, rs1885088 and rs3818247 respectively. Results: The risk allele of the rs1884614, which is located 4 kb upstream of the HNF4A P2 promoter, was associated with type 2 diabetes (odds ratio [OR]=1.14, p=0.02) and with a subtle increase in post-OGTT plasma glucose levels in glucose-tolerant subjects (additive model, p=0.05). Conclusions/ interpretation: Consistent with results from studies of Finnish and Ashkenazi Jewish subjects, variation near the P2 region of HNF4A is associated with type 2 diabetes in the Danish population.

Aims/hypothesis. The class III allele of the variablenumber-of-tandem-repeats polymorphism located 5′ of the insulin gene (INS-VNTR) has been associated with Type 2 diabetes and altered birthweight. It has also been suggested, although inconsistently, that the class III allele plays a role in glucose-induced insulin response among NGT individuals. Methods. We investigated the impact of the class III allele on Type 2 diabetes susceptibility in a case-control study involving 1462 Type 2 diabetic patients and 4931 NGT subjects. We also examined the potential impact of the class III allele in genotype-quantitative trait studies in three Danish study populations containing (i) 358 young healthy subjects; (ii) 4444 middleaged NGT subjects, 490 subjects with IFG and 678 subjects with IGT; and (iii) 221 NGT subjects, of whom one parent had Type 2 diabetes.Results. There was no difference in frequency of the class III allele or in genotype distribution between the 1462 Type 2 diabetic patients and the 4931 NGT subjects. Among the 358 young subjects the class III/III carriers had significantly reduced post-IVGTT acute serum insulin and C-peptide responses (p=0.04 and 0.03 respectively). However, among the 4444 middleaged subjects we failed to demonstrate any association between the class III allele and post-OGTT serum insulin and C-peptide levels. Conclusions/interpretation. The class III allele of the INS-VNTR does not confer susceptibility to Type 2 diabetes or consistent alterations in glucose-induced insulin release in the examined populations, which consisted of Danish Caucasians.

HNF4A encodes an orphan nuclear receptor that plays crucial roles in regulating hepatic gluconeogenesis and insulin secretion. The aim of the present study was to examine two rare missense polymorphisms of HNF4A, Thr130Ile and Val255Met, for altered function and for association with type 2 diabetes (T2D). We have examined these polymorphisms 1) by in vitro transactivation studies and 2) by genotyping the variants in 1409 T2D patients and in 4726 glucose-tolerant Danish white subjects. When tested in COS7 cells, both the Thr130Ile and the Val255Met variants showed a significant decrease in transactivation activity compared with wild-type (73% of wild-type, P = 0.02, and 76%, P = 0.04, respectively). The Thr130Ile variant had a significantly increased carrier frequency among T2D patients compared with glucose-tolerant subjects [odds ratio, 1.26 (1.01-1.57); P = 0.04]. The rare Val255Met polymorphism had a similar frequency among T2D patients and glucose-tolerant subjects. Heterozygous glucose-tolerant carriers of the variant showed, however, decreased levels of fasting serum C-peptide (76%; P = 0.03) and decreased fasting serum triglyceride (58%; P = 0.02). In conclusion, The Thr130Ile and the Val255Met polymorphisms decrease the transcriptional activity of HNF4A, and the Thr130Ile polymorphism associates with T2D, whereas the Val255Met variant associates with a decrease in fasting serum C-peptide.