Evidence check: FTO in the context of Müdigkeit

The link between FTO variants (e.g., rs9939609) and fatigue is indirect and weakly supported by evidence. FTO is strongly associated with fat mass and obesity risk; carriers of the risk allele tend to have slightly higher BMI and altered appetite regulation. Obesity can contribute to fatigue through sleep apnea, low-grade inflammation, and metabolic strain. However, a direct causal effect of FTO on tiredness or low energy is not established. The evidence is mechanistic (FTO involved in energy homeostasis) and epidemiological (BMI association), but insufficient for individual fatigue prediction. A consumer DNA test like MyBody-X can indicate obesity predisposition, but cannot diagnose fatigue causes. Clinical workup (thyroid, iron, sleep, stress) remains essential. Caveat: Fatigue is multifactorial; a single gene variant explains negligible variance.