Monogenic obesity refers to obesity resulting from mutations in a single gene. It is less common than polygenic obesity, which involves variations in multiple genes and is influenced by environmental factors. Monogenic obesity typically manifests early in life and can lead to severe obesity and often, resistance to traditional weight loss methods, including diet and exercise. Here are some examples of genes involved in monogenic obesity:

• Leptin (LEP) Gene Mutations : Leptin is a hormone produced by fat cells. It regulates energy balance by inhibiting hunger, which in turn diminishes fat storage in adipocytes. Mutations in the LEP gene can lead to a lack of leptin, resulting in severe early-onset obesity and intense hunger.
• Leptin Receptor (LEPR) Gene Mutations : The LEPR gene encodes the leptin receptor, which is necessary for the normal function of leptin. Mutations in this gene can lead to leptin resistance, causing severe obesity due to the inability to regulate appetite and energy expenditure effectively.