The Influence of the Rs7566605 in Overweight in Different Populations – A Systematic Review

Introduction: Obesity and overweight are major worldwide public health problems associated with several etiological factors. The rs7566605 polymorphism in the INSIG-2 gene is reported to be associated with the development of obesity. This polymorphism occurs when there is a change in the nitrogenous base guanine (G) for cytosine (C) resulting in two possible mutant genotypes: CC and CG. The wild genotype is represented by GG. Many authors reported the association between this polymorphism with anthropometrical changes, but there is no consensus regarding this issue. Objective: to evaluate the frequency of rs7566605 polymorphism and its association with obesity markers in populations from different geographical areas. Method: systematic review using PubMed and following the PRISMA Guidelines. Results: there was a great variability in terms of sample size, areas, bias and phenotypic characteristics. Although 38 biological traits were evaluated, the mutation was associated with only three of them (BMI, Waist-Hip Ratio, HbA1c). The highest CC frequency was found among obese Malays (21%), and the lowest among overweight Quilombo people (3%). The highest CG frequency was found in non-obese Malays (51%), while the lowest was reported among overweight Quilombo people (22%). Also, Quilombo people reported the highest frequency of the GG phenotype (75%), while the lowest frequency was found in non-obese Malays (32%). Conclusion: The polymorphism was associated with only three obesity markers. There were specific patterns of genotypic frequency among populations belonging to similar geographical areas and/or ancestry. More research into the genetic factors related to obesity markers is needed.