The function of WFDC2 (WAP four-disulfide core domain 2, ENSG00000101443) is as follows. Plays a critical role in lung development (By similarity). Required for terminal differentiation of bronchiole club cells (By similarity). Required for development of airway barrier mechanisms, such as lamellar body formation in type II alveolar epithelial cells and cilia formation on ciliated epithelial cells following initiation of respiration at birth (By similarity). Required for type I alveolar epithelial cell and vascular endothelial development in the lungs, thereby mediating blood-air barrier exchange (By similarity). .