Combined genome-wide linkage and association analyses for the fasting glucose level in Korean healthy twins and their families

초록

Type 2 diabetes involves a major chronic disease to impact on the public health and a main reason of morbidity and mortality worldwide. The fasting glucose (FG) level is one of the traits related to type 2 diabetes. We explored a quantitative trait of the FG level for which we wish to determine markers out of more than 900,000 markers being considered in genome-wide study in Korean healthy twin-family cohort including monozygotic twins and their families. We investigated 1,754 individuals including 432 families through the combined approaches of linkage analysis with family-based association studies. We identified the regions of chromosome 2q23.3-2q31.1, 15q26.1-15q26.3, 16p12.1, and 20p13-20p12.2, showing evidence of linkage with FG level in genome-wide linkage analysis. We found several known markers and novel markers in these regions which were significantly detected through the association analysis. In addition, we verified significant epistatic effects of the significantly identified genes which confer a risk of the increased FG level. We could identify evidence of genetic signals more accurately using twin and their families in this study. These findings for FG level may be valuable to predict occurrence of type 2 diabetes in Korean population.