To date multiple studies have tried to elucidate genetic factors contributing to the etiopathogenesis of obesity, and relevant SNPs in more than 100 loci have been identified by Genome Wide Association Studies (GWAS), including those near genes such as FTO (MIM 610966), MC4R, NEGR1 (MIM 613173) or TMEM18 (MIM 613220) [12–15]. Here, MC4R is linked to obesity due to melanocortin 4 receptor deficiency.