LEP and metabolic syndrome: Regarding SNP rs1137101, which we demonstrated to be related to an increased risk for DTC, reports in the literature have shown that variants of LEPR are related to the following: increased BMI, insulin resistance, and correlation with HOMA-IR (an index used for the assessment of insulin resistance), metabolic syndrome, increased fat mass and adipocytes, increased waist circumference, obesity, development of type 2 diabetes mellitus (T2DM), and serum concentrations of circulating leptin [39–52].