CSF2 and pulmonary alveolar proteinosis: There are three clinically distinct forms of PAP: congenital (2% of cases), acquired (also referred as primary or idiopathic, 90%), and secondary (5 to10%) [2].Congenital PAP is a heterogeneous collection of disorders caused by homozygous mutation of the genes encoding surfactant proteins (SP)-B and SP-C and the ABCA3 (ATP-binding cassette, sub-family A, member 3) transporter, or by the absence of the granulocyte macrophage colony-stimulating factor (GM-CSF) receptor [3,5].