Although the pathomechanism of these conditions still needs further clarification (eosinophilic esophagitis is the most studied subtype of these disorders), available data indicates an allergic background (caused by food allergens such as cow’s milk, peanut, or egg) of mixed immunologic mechanisms (IgE- and non-IgE-mediated) [13]. The gene discussed is IGHE; the disease is eosinophilic esophagitis.