Polymorphisms of Kir6.2 Gene are Associated with Type 2 Diabetes and Blood Pressure in the Korean Population

Koo, Bo Kyeong; Kim, Hong Il; Lee, Eu Jin; Cho, Young Min; Shin, Hyoung Doo; Jang, Hak Chul; Lee, Hong Kyu; Park, Kyong Soo

Abstract

BACKGOUND: ATP-sensitive potassium channels are a heterooctamer of SUR1 and Kir6.2, which are key components in the insulin secretory mechanism. Whether common variants in the Kir6.2 gene are associated with type 2 diabetes and/or its associated phenotypes was investigated.
METHODS
The Kir6.2 gene was sequenced in 24Korean DNA samples to identify common polymorphisms (frequency > 0.05). The common variants found among these samples were genotyped in a larger population including type 2 diabetic patients and nondiabetic subjects.
RESULTS
Thirteen single nucleotide polymorphisms and one insertion/deletion polymorphism were identified in the Kir6.2 gene, with six common variants(g.-1709A>T, g.-1525T>C, g.67G >A [E23K], g.570C>T [A190A], g.1009A>G [1337V], and g.1388C>T) genotyped in 761 type 2 diabetic patients and 675 nondiabetic subjects. Four individual polymorphisms(g.-1525T > C, g.67G>A, g.1009A>G and g.1388C>T) appeared to be associated with type 2 diabetes (age, sex and BMI-adjusted odds ratio[OR]=0.751[0.584-0.967] in the recessive model on g-1525T>C, 1.193 [1.020-1.394] in the additive model in g.67G>A, 1.195 [1.022-1.399] in the additive model on g.1009A>G, 0.835 [0.717-0.973] in the additive model in g.1388C >T). The haplotype "ATACGC" in the Kir6.2 gene, composed of rare allele in the g.67 and g.1009, was also associated with a higher prevalence of type 2 diabetes (age, sex, and BMI- adjusted OR = 1.256 [1.067-1.479], P for logistic regression = 0.006). In addition g.67G>A and g.1009A >G in the KCNJ11 were strongly associated with a high systolic blood pressure.
CONCLUSION
Polymorphisms in the Kir6.2 gene are associated with type 2 diabetes and blood pressure in the Korean population.