Pulmonary alveolar microlithiasis is an autosomal recessive disease that causes calcium phosphate deposition within the alveoli of the lungs. These microlith deposits eventually damage the alveoli and interstitium of the lung.

Patients may present with dyspnea and cough, although in the majority of patients, diagnosis is made by radiography incidentally. At diagnosis, the majority of patients are asymptomatic, and individuals may not present with symptoms until 30-40 years of age. As the disease progresses, pulmonary function tests will show a restrictive lung disease, and patients may develop pulmonary hypertension, although the rate of progression is variable. Pulmonary alveolar microlithiasis may be associated with tuberculosis.

Pulmonary alveolar microlithiasis is caused by a mutation in the SLC34A2 gene, which helps regulate phosphate levels and production of protein in alveolar type II cells. The majority of cases have been reported in the United States, Europe, and Asia.

There are no specific treatments for pulmonary alveolar microlithiasis.