CSF2 and hereditary disease: PAP is caused by (i) genetic diseases which result in dysfunction of surfactant or surfactant production (SFTPC, SFTPB, ABCA3, TTF1 deficiency) mainly presenting during infancy, by (ii) disruption of GM-CSF signaling from mutations in the receptor (GM-CSFRa, GM-CSFRb) or from acquired autoantibodies against GM-CSF, and by (iii) disorders that presumably impair surfactant clearance because of abnormal numbers or defective phagocytic functions of alveolar macrophages [2].