Evaluation of the role of FTO (rs9939609) and MC4R (rs17782313) gene polymorphisms in type 1 diabetes and their relation to obesity

Objectives: This study aims to explore the effects of fat mass obesity-associated (FTO) (rs9939609) and melanocortin 4 receptor (MC4R) (rs17782313) gene polymorphisms in children with type 1 diabetes (T1D) and their relation to obesity.

Methods: Fat mass obesity-associated (FTO) (rs9939609) and melanocortin 4 receptor (MC4R) (rs17782313) gene polymorphisms were evaluated in 164 patients and 100 controls, and genotypes, alleles, and haplotype frequencies were compared between cases and controls.

Results: A significant association with T1D development was found with the TC, CC, and TC+CC genotypes and the C allele of MC4R rs17782313. In addition, TA, AA, and TA+AA genotypes and the A allele of FTO rs9939609 may also be risky for T1D development. While the TC and TC+CC genotypes of MC4R rs17782313 may be protective against obesity development, the AA genotype and A allele of FTO rs9939609 may also be protective against obesity development. Regarding obese subjects, comparing diabetics vs. non-diabetic studied subjects, FTO rs9939609, TA, AA, and TA+AA genotypes and the A allele had significantly higher frequencies in T1D with a higher risk of developing T1D. However, conducting multivariable analysis using significant covariates in univariable analysis revealed that only earlier age of T1D onset, lower C-peptide, and the MC4R dominant model were considered independent predictors of obesity within T1D.

Conclusions: The role of both genes' polymorphisms on the pathogenesis and the outcome of T1D and obesity can help in understanding the pathogenesis of both diseases and their associations with each other's and may be used as novel therapeutic targets for both diseases.