Myths vs facts: FUT2 and allergy

FUT2 (fucosyltransferase 2) is best known for its role in vitamin B12 absorption. Variants like rs602662 or rs492602 affect the secretion of blood group antigens and thereby B12 status. Some GWAS have also linked FUT2 variants to allergy risk (e.g., hay fever, atopic dermatitis), but the effects are small and inconsistent. The evidence is weaker than for B12. A DNA test cannot predict allergy risk – IgE blood levels or symptoms are far more informative. Bottom line: FUT2 is not a clinical 'allergy gene'. Myths that a specific variant directly causes allergies are overblown. The actual predictive power is low, and lifestyle/environmental factors dominate.