ADGRF5 and pulmonary alveolar proteinosis: The existence of such numerous proteins involved in the regulation of lung lipid homeostasis entails a broad etiology for PAP, including alterations of re-uptake/catabolism by AE2C or AM (as autoantibodies to GM-CSF, absence or alteration in GM-CSF receptors colony stimulating factor 2 receptors alpha and beta, ABCA1, ABCG1, SP-D and GPR116) or of surfactant secretion (GPR116).