The aim of this study is to investigate the alterations of serum levels of leptin, adiponectin, and CRP after nonsurgical periodontal treatment (NSPT) in Thai patients with overweight or obesity (Owt/Ob) who did or did not exhibit severe periodontitis (SP) and normal weight (Nwt) patients with or without SP. The gene discussed is LEP; the disease is obesity due to melanocortin 4 receptor deficiency.