Genome-wide linkage analysis and regional fine mapping identified variants in the RYR3 gene as a novel quantitative trait locus for circulating adiponectin in Chinese population

Adiponectin is adipocyte-secreted cytokine with potent insulin-sensitizing action in peripheral tissues. The heritability of plasma adiponectin is high in Han Chinese population. To identify genetic loci influencing plasma adiponectin levels in Chinese population, we performed a genome-wide linkage scan in 1949 Chinese participants of the Stanford Asia-Pacific Program for Hypertension and Insulin Resistance family study and mapped a quantitative trail locus located on chromosome 15 at 31cM (logarithm of odds=3.04) with 1-logarithm of odds support interval at 24 to 34cM. Within this mapped region, we further genotyped a total of 68 single-nucleotide polymorphisms in 12 genes. Association analysis revealed that haplotypes composed of single-nucleotide polymorphisms in the ryanodine receptor 3 (RYR3) gene had strongest association with plasma adiponectin. RYR3 haplotypes were also associated with systolic (P=0.001) and diastolic (P= 7.1-10-4) blood pressure and high-density lipoprotein cholesterol (P=1.4-10-4). Furthermore, an inverse relationship between expression of RYR3 and adiponectin was observed in human abdominal adipose tissue. In conclusion, a genome-wide linkage scan and regional association fine-mapping identified variants in the RYR3 gene as a quantitative trail locus for plasma adiponectin levels in Chinese population.