Familial occurrence of pulmonary alveolar microlithiasis in 3 siblings.

Pulmonary alveolar microlithiasis (PAM) is a rare disease of unknown etiology characterized by intra-alveolar calcium deposits. More than 500 cases were reported in the literature. The disorder affects people at every age beginning from the early childhood. It occurs probably as a result of autosomal recessive transmission. Familial occurrence is often found with family history of the disease being present in up to 50% of the reported cases. We report PAM in 3 siblings.