Nikpay et al. conducted a genome-wide search for DNA methylation sites that lead to obesity and identified seven CpG sites that have a causal relationship with the risk of obesity, namely cg21178254 (CCNL1), cg06028605 (SLC5Al1), cg02814054 (MAST3), cg02814054 (POMC, ADCY3, and DNAJC27), and cg01884057 (POMC, ADCY3, and DNAJC27) [40]. This evidence concerns the gene CCNL1 and obesity due to melanocortin 4 receptor deficiency.