Evidence check: MTHFR in the context of Allergie

The link between MTHFR variants (especially C677T) and allergies remains controversial. Mechanistically, impaired methylation may elevate homocysteine and influence immune function or epigenetic regulation, potentially affecting allergic risk. Some observational studies report associations with asthma, atopic dermatitis, or elevated IgE, but effect sizes are small and findings inconsistent. Crucially, MTHFR testing from consumer DNA kits is not a diagnostic tool for allergies. Clinical relevance is unclear because environmental triggers, diet, and other genetic factors dominate. No randomized trials or guidelines support MTHFR-based allergy management. Evidence: mechanistic/mixed. Caveat: Do not change treatment based on MTHFR alone. For allergy evaluation, standard methods (skin prick test, specific IgE) and medical consultation are essential.