Table 1

Proposed classification of paediatric PAP

Category of diseaseExemplar conditions
Disorders of surfactant protein metabolismSFTPB, STFPC, ABCA3 and TTF1 mutations
GM-CSF receptor gene mutationsα- and β-chain mutations
Other genetic disordersMARS, STING, COPA and GATA2 mutations
Metabolic diseaseLysinuric protein intolerance, Niemann–Pick disease
Associated with immune deficiency
 CongenitalSCID, ADA deficiency
 AcquiredHIV, leukaemia
Associated with connective tissue diseaseIdiopathic juvenile chronic arthritis
MiscellaneousCongenital heart disease
Diseases seen in adults
 Exclusively in adultsMacrophage blockade, lymphoma
 Mainly in adultsAutoimmune

GM-CSF: granulocyte–macrophage colony-stimulating factor; STFPB: surfactant protein B; STFPC: surfactant protein C; ABCA3: ATP-binding cassette 3; TTF1: thyroid transcription factor 1; MARS: methionyl transfer RNA synthetase; STING: stimulator of interferon; COPA: non-clathrin-coated vesicular coat protein A; GATA2: GATA-binding protein 2; SCID: severe combined immunodeficiency; ADA: adenosine deaminase.