Evidence check: LCT in the context of allergy

The question about LCT in the context of allergy reflects a common confusion. LCT encodes lactase, the enzyme that digests lactose. Variants like rs4988235 determine lactase persistence and thus tolerance to dairy. Lactose intolerance is a digestive issue, not an allergy. True milk allergy involves immune reactions (e.g., IgE to milk proteins) and is not linked to LCT variants. There is no strong evidence that LCT SNPs influence allergy risk. Some GWAS have explored associations with atopy, but effect sizes are tiny and inconsistent. Consumer DNA tests may report LCT status, but this should not be misinterpreted as an allergy marker. For suspected milk allergy, specific IgE testing or oral food challenges are required. Evidence grade: unclear – the mechanistic link is weak and clinically irrelevant. Sources: no specific PMIDs provided in the context.