Myths vs facts: MC4R and Langlebigkeit

MC4R (melanocortin-4 receptor) is a key regulator of energy balance and appetite. Loss-of-function mutations are the most common monogenic cause of early-onset obesity. A common myth is that MC4R variants directly determine lifespan. In reality, while MC4R polymorphisms are robustly associated with BMI and obesity—which can indirectly affect longevity through metabolic diseases—there is no strong evidence for a direct link between MC4R and human lifespan. Evidence is largely mechanistic (animal models, pathway studies) and based on association studies. Genome-wide association studies on longevity have not identified MC4R as a significant locus. Conclusion: MC4R is important for weight regulation but not a 'longevity gene'. Direct-to-consumer DNA tests claiming to predict lifespan from MC4R are misleading. Clinical relevance is limited to obesity diagnostics. If a MC4R mutation is suspected, medical consultation is advised.