A gene called CAPN14 has been identified as a novel genetic component in epithelial tissue in the esophagus, and the gene’s interaction with the immune hormones thymic stromal lymphopoietin (TSLP) and interleukin 13 (IL-13) may explain why some patients develop eosinophilic esophagitis (EoE), a hard-to-treat food allergy marked by chronic inflammation of the esophagus.