It is likely that higher concentrations of MMP-2, MMP-9 and IL-1β can be detected in the saliva of obese women compared to non-obese women, while higher concentrations of MMP-9, IL-6 and resistin can be found in the saliva of obese men compared to non-obese men, which suggests that further research to confirm our observations and determine the mechanisms of development of metabolic complications associated with obesity depending on gender is needed. The gene discussed is MMP9; the disease is obesity due to melanocortin 4 receptor deficiency.