Studies of variability in the islet amyloid polypeptide gene in relation to Type 2 diabetes

Aims: To explore whether the coding region of the islet amyloid polypeptide (IAPP) gene contains genetic variants associated with Type 2 diabetes and whether a previously reported association of the promoter variant -132g→a with Type 2 diabetes could be reproduced in Danish Caucasians. Methods: The coding region was analyzed using single strand conformation polymorphism (SSCP) and heteroduplex analysis in 192 Type 2 diabetic patients. Restriction fragment length polymorphism (RFLP) was employed to screen for the promoter variant in 414 Type 2 diabetic patients and 182 glucose-tolerant control subjects. Results: The SSCP analysis identified an IVS+75a→g variant in two patients. The frequency of heterozygous carriers of the promoter variant in the case-control study was 4.1% (17/414) and 7.1% (13/182), respectively. Odds ratio of the prevalence of Type 2 diabetes in carriers compared with non-carriers was estimated to be 0.47 (95% confidence interval 0.19, 1.15). Conclusion: Neither variability in the coding region of the IAPP gene nor the -132g→a promoter variant was associated with Type 2 diabetes among the studied Danish Caucasians.