A frame-shift mutation in the SLC34A2 gene in three patients with pulmonary alveolar microlithiasis in an inbred family.

Pulmonary alveolar microlithiasis (PAM) is a rare disease characterized by the presence of small calculi in the alveolar space. The SLC34A2 is thought to be responsible for the disease. We encountered three siblings of an inbred family who have PAM. We examined the family of the proband who was admitted with dyspnea on exertion and cough, and eventually was diagnosed with PAM. Genetic analysis revealed that both parents (a consanguineous marriage) of the proband were carriers with heterozygous mutation of SLC34A2 gene, and three of their children were diagnosed with PAM with homozygous mutation in the SLC34A2 gene. These findings suggest that impaired activity of the SLC34A2 gene may be responsible for familial PAM.