No association between INSIG2 gene rs7566605 Polymorphism and being overweight in Japanese population

Abstract

Obesity is a complex trait reflecting numerous genetic and environmental factors. Recently, a common genetic polymorphism (rs7566605) associated with a higher BMI was found in proximity to the insulin induced protein 2 (INSIG2 ) gene, with replication in four unrelated populations living in Western countries. We investigated the susceptibility to the polymorphism amongst the general Japanese population (n 1976). The frequency of appearance of the single-nucleotide polymorphism (SNP) in the Japanese (G allele; 0.652, C allele; 0.348) was not different from that found in subjects of European origin as reported previously. However, the BMI levels in each of these genotypes did not differ significantly (GG; 23 ± 3, GC; 24 ± 3, CC; 24 ± 3 kg/m2, P 0.906). In a separate analysis according to sex (male; P 0.462, female; P 0.879), age decade (40s; P 0.057, 50s; P 0.998, 60s; P 0.622, 70s; 0.425, respectively), and tertiles of the BMI (1st; P 0.409, 2nd; P 0.088, 3rd; P 0.780), the differences did not achieve statistical significance. The frequency of obesity did not differ among the genotypes (25 kg/m2; 30.3, 30.8, 28.2, P 0.729, 30 kg/m2; 2.9, 3.8, 2.8, P 0.549). No associations were also observed for related plasma markers; high-molecular weight (HMW) adiponectin (P 0.510), high-sensitive C-reactive protein (P 0.788), resistin (P 0.937) and homeostasis of minimal assessment of insulin resistance (P 0.634). These results indicate a lack of association between SNP rs7566605 and being overweight among the Japanese (in the middle-aged and elderly population). © 2008 The Obesity Society.