Association of the Common Genetic Variant Upstream of INSIG2 Gene with Obesity Related Phenotypes in Chinese Children and Adolescents

Objective: To study the association between the rs7566605 variant of INSIG2 and obesity-related phenotypes in Chinese children and adolescents.

Methods: The study sample consisted of two independent cohorts of Chinese children and adolescents. Anthropometric indices, lipids, blood pressure, fasting glucose, insulin and percentage of fat mass were determined. PCR with restriction fragment length polymorphism analysis was performed for genotyping the rs7566605 variant.

Results: In each of the two independent cohorts, no significant association was observed between rs7566605 and obesity under additive, dominant or recessive model. We also did not detect any difference in the genotype frequency between all the obese children and controls. Furthermore, we did not find evidence of an association between body composition indices and metabolic phenotypes in all children. However, the triglyceride level of CC homozygotes was significantly higher than that of GG+GC genotypes in obese children (P=0.022). Additionally, we observed a non-significant trend of severe obesity in a post-hoc test.

Conclusion: INSIG2 rs7566605 variant is not associated Chinese childhood obesity in two independent cohorts. Further study is needed to verify the effect of rs7566605 on triglyceride in obese children.