In agreement with a previous study carried out in muscle [38], we found herein that the hypomethylation of the promoter site -783 CpG of the PPARGC1A gene in leukocytes measured by pyrosequencing (not included in the Illumina Methylation 450K array) might represent a biomarker of reduced insulin sensitivity (or enhanced insulin resistance) (Figure 3 and Figure 4). This evidence concerns the gene PPARGC1A and Insulin resistance.