Evidence check: MC4R in the context of Abnehmen

The MC4R gene encodes the melanocortin-4 receptor, a key player in appetite regulation and energy balance. Rare loss-of-function mutations cause monogenic obesity with early onset and severe hyperphagia. Common variants (e.g., rs17782313 near MC4R) are robustly associated with increased BMI in large GWAS, but each risk allele contributes only a small effect (~0.5 kg per allele). Evidence is human-strong (multiple GWAS, functional studies). However, a single SNP cannot determine metabolic rate or weight loss success. Weight regulation is polygenic and heavily influenced by diet, physical activity, and other lifestyle factors. Consumer DNA tests that market MC4R as a 'weight loss gene' overstate its predictive power. A genetic test alone does not replace a comprehensive assessment including blood biomarkers (e.g., fasting insulin, HbA1c) and professional dietary counseling. Safety note: In cases of severe early-onset obesity, clinical genetic testing for rare MC4R mutations may be indicated. For the general public, DTC testing for MC4R variants has limited actionable value.