It was reported that the methylation levels of peroxisome proliferator-activated receptor-gamma (PPARγ) coactivator 1a (PPARGC1A), a key regulator of mitochondrial biogenesis [127], and mitochondrial transcription factor A (TFAM) in the livers of patients with NAFLD were relevant to the IR phenotype [115]. This evidence concerns the gene PPARG and metabolic dysfunction-associated steatotic liver disease.