How are FUT2 and fatigue related?

The provided knowledge does not establish a direct relationship between FUT2 and fatigue. FUT2 determines secretor status, influencing gut microbiome composition and susceptibility to certain infections. Fatigue is a complex symptom with many causes (e.g., sleep deprivation, stress, nutritional deficiencies). While an indirect link via microbiome or immune modulation is theoretically plausible, no human studies or clinical data in the context support a FUT2-fatigue connection. The only FUT2 variant mentioned (rs1047781) is associated with skin health, not fatigue. Therefore, any claim of a direct genetic effect on fatigue from FUT2 is speculative. Fatigue assessment should rely on comprehensive clinical evaluation rather than this single gene.