In this work, we gained important insights into the association of GR genetic polymorphisms/haplotypes, DNA methylation markers, and gene expression in the leukocytes of South Brazilian Mennonites with MetS, where we investigated 25 NR3C1 polymorphisms, the methylation levels of 11 CpGs mapped to the 1F region, and NR3C1 mRNA levels. Here, NR3C1 is linked to metabolic syndrome.