Heritability of obesity-related phenotypes and association with adiponectin gene polymorphisms in the Chinese national twin registry.

The purpose of this study was to estimate the heritability of obesity-related phenotypes and investigate the association of adiponectin gene polymorphisms +45T>G and +276G>T with these measures in Chinese twins. 1260 twin pairs were recruited from two cities through the Chinese National Twin Registry System from 2001 to 2005. Two SNPs at the adiponectin locus (+45T>G and +276G>T) were genotyped. Structural equation modeling (SEM) was used to estimate heritability and the best-fitting variance component model. The regular association among all twins was analysed with generalised estimating equations (GEE). Sib-transmission/disequilibrium test (TDT) within dizygotic (DZ) twin pairs discordant for their genotype was performed using SEM. Additive genetic, common and unique environmental (ACE) model-based heritability of body mass index (BMI) was 61%, while additive genetic and unique environmental (AE)-model-based heritability of waist circumference (WC) and waist-hip ratio (WHR) were 75% and 61%, respectively. There was no association of adiponectin gene +45T>G and +276G>T genotypes with obesity-related phenotypes in all twins or discordant DZ twins. Our twins data did not support that there was an association between adiponectin gene polymorphisms +45T>G and +276G>T and the obesity-related phenotypes. Further studies are required to better understand the role of adiponectin gene polymorphisms in obesity.