Adult-onset hereditary pulmonary alveolar proteinosis caused by a single-base deletion in CSF2RB.

Background Disruption of granulocyte/macrophage colony-stimulating factor (GM-CSF) signalling causes pulmonary alveolar proteinosis (PAP). Rarely, genetic defects in neonatal or infant-onset PAP have been identified in . However, no report has clearly identified any function-associated genetic defect in . Methods and results The patient was diagnosed with PAP at the age of 36 and developed respiratory failure. She was negative for GM-CSF autoantibody and had no underlying disease. Signalling and genetic defects in GM-CSF receptor were screened. GM-CSF-stimulated STAT5 phosphorylation was not observed and GM-CSF-Rβc expression was defective in the patient's blood cells. Genetic screening revealed a homozygous, single-base deletion at nt 631 in exon 6 of on chromosome 22, which caused reductions in GM-CSF dependent signalling and function. Both parents, who were second cousins, showed no pulmonary symptoms, and had normal GM-CSF-signalling, but had a allele with the identical deletion, indicating that the mutant allele may give rise to PAP in an autosomal recessive manner. Conclusions This is the first report identifying a genetic defect in that causes deficiency of GM-CSF-Rβc expression and impaired signalling downstream. These results suggested that GM-CSF signalling was compensated by other signalling pathways, leading to adult-onset PAP. [ABSTRACT FROM PUBLISHER]