A meta-analysis has shown that obesity can alter serum levels of pro-inflammatory mediators (i.e., IL-6, CRP, TNF-a, resistin and leptin) in patients with periodontitis, while periodontitis can alter the levels of these mediators in patients with obesity, aggravating the inflammatory profile [61]. The gene discussed is TNF; the disease is obesity due to melanocortin 4 receptor deficiency.