Adipose tissue is an active endocrine organ releasing several adipokines and inflammatory factors, including adiponectin, leptin, resistin, chemotactic protein 1 (MCP-1), TNF-α, IL-6, IL-1β, IL-10, and transforming growth factor (TGF)-β, which may contribute to the differential impact of obesity in the two genders. This evidence concerns the gene RETN and obesity due to melanocortin 4 receptor deficiency.