PCDH1 and allergic disease: WNT proteins in our model included LRP5 and Axin2, which regulate airway branching and alveolar morphogenesis in fetal lungs (46–48), and Nfatc2 (49, 50) and PCDH1 (51–53), which are novel susceptibility loci for allergy and bronchial hyperreactivity in humans, respectively.