The succinate dehydrogenase (SDH) complex (SDHAF1), which encodes a protein essential for the assembly of mitochondrial enzyme succinate dehydrogenase (SDH), the main element of complex II45, was hypermethylated in its promoter region in obesity and further hypermethylated in CRC. This evidence concerns the gene SDHAF1 and obesity due to melanocortin 4 receptor deficiency.