Acquired pulmonary alveolar proteinosis (PAP)
is a rare, acquired lung disorder characterized by the accumulation of grainy material consisting mostly of protein and fat (lipoproteinaceous material) in the air sacs of the lungs (alveoli). Most cases affect adults between the ages of 20-50. The symptoms can vary greatly; some individuals may not show symptoms, while others may experience progressive difficulty breathing and shortness of breath upon exertion. Other signs and symptoms may include a dry, chronic cough; fatigue; weight loss; chest pain; and a general feeling of ill health. In rare cases, the coughing up of blood, rounding and swelling of the tips of the fingers, and cyanosis may be present. Most cases occur for no known reason, but some cases may occur secondary to environmental exposures or underlying diseases; some researchers believe it may be an autoimmune disorder. The treatment varies from case to case depending upon the age of the affected individual and severity of the disease. Acquired PAP differs from congenital PAP, an extremely rare form of PAP that occurs in some newborns. Source: Genetic and Rare Diseases Information Center (GARD), supported by ORDR-NCATS and NHGRI.