Analyzing the heterogeneous group of pre-school asthma, the following phenotypes have been characterized (12–14): asthma with sensitization defined by specific IgE (sIgE) > 0.7 KU/L and/or a positive skin prick-test to common allergens, eosinophilic asthma with elevated blood eosinophils (>300 eosinophils/μl) without presence of sensitization, and non-allergic asthma without TH2- inflammation. This evidence concerns the gene IGHE and allergic asthma.