LEP and obesity due to melanocortin 4 receptor deficiency: This may be because obesity increases the mechanical load of articular cartilage, leading to its degradation, and fatty tissue secretes metabolic factors (such as IL-1, TNF-A, adiponectin, and leptin), leading to an increased prevalence of OA in obese people (Oliveria et al., 1999; Grotle et al., 2008; Kalichman and Kobyliansky, 2009).