Loss-of-function variants of the filaggrin gene are associated with clinical reactivity to foods.

The aim of this study was to assess the genetic association of Filaggrin loss-of-function (FLG LOF) genetic variants with food allergy, and to investigate the added value of this test in diagnosing food allergy. Clinical reactivity to foods was diagnosed by the gold standard, the double-blind, placebo-controlled food challenge. Of 155 children, 33 (21.3%) children had at least one FLG LOF variant, and of these, 29 (87.9%) were clinically reactive to at least one food, compared to 73 of 122 children (59.8%) carrying wild-type alleles. The odds ratio for having at least one FLG LOF variant and clinical reactivity to at least one food was 4.9 (CI = 1.6-14.7, P = 0.005), corresponding to a relative risk of 1.5, compared to carriers of wild-type alleles. Prediction of food allergy improved when FLG LOF variants were included in the model. Therefore, genetic markers may be useful as an addition to clinical assessment in the diagnosis of food allergy.