Insulin resistance, decreased plasma levels of adiponectin (hypoadiponectinemia) and decreased plasma levels of resistin are reportedly related to obesity and type 2 diabetes mellitus in patients (Way et al., 2001; Fasshauer et al., 2002; Möhlig et al., 2002; Heilbronn et al., 2004; Mojiminiyi et al., 2007; Chen et al., 2014). This evidence concerns the gene RETN and obesity due to melanocortin 4 receptor deficiency.