SLC34A2 Gene mutation of pulmonary alveolar microlithiasis: report of four cases and review of literatures.

Pulmonary alveolar microlithiasis (PAM) is a rare autosomal recessive disorder characterized by the deposition of calcium phosphate microliths throughout the lungs. Currently the mutation of SLC34A2 gene was considered responsible for PAM. Here we reported the studies on mutation analysis of the SLC34A2 gene in three familial members and one unrelated subject of PAM by DNA direct sequencing. Meanwhile, we also reviewed and analyzed the published studies of the SLC34A2 gene mutation in PAM patients. The three familial patients were siblings of an inbred family whose parents were cousins. All four patients presented recurrent cough and exertional dyspnea. Diagnosis of PAM was made according to the typical manifestation of radiology. One homozygous mutation of the SLC34A2 gene, c.910A > T (p.K304X) was identified. The review of the SLC34A2 gene mutation showed multiple mutation symbols in PAM patients from China, Turkey, and Japan respectively. The present study supports that the clinical features, pathological and radiological characteristics of Chinese PAM patients are similar to those reported in other countries. Our investigation revealed that the c.910A > T mutation in the SCL34A2 gene was responsible for PAM patients in China. The review of literatures suggests that exon7 and exon8 seemed liable to be affected typical Mongoloid of PAM, and exon8 might be the screen target for Chinese patients.