Common Mutations in the Surfactant Protein-C Gene in Iranian Patients with Diffuse Parenchymal Lung Disease.

Abstract

Background: Recently, genetic mutations in surfactant protein C (SFTPC) have been linked to diffuse parenchymal lung diseases (DPLD). The present study investigated SFTPC mutations among Iranian patients with DPLD for the first time.

Materials and methods: In this study, we examined 28 patients diagnosed with DPLD. Patients were divided into two groups: 23 cases (82.1%) had interstitial lung disease (ILD), 7 (30.4%) of which were categorized as familial ILD, and 5 cases (17.9%) had pulmonary alveolar proteinosis (PAP). Genetic variations in the SFTPC gene were detected by direct DNA sequencing.

Results: The mean (±SD) age of patients was 21.8 (± 17.1) years and 60.7% of the patients were male. Overall, 11 different mutations were detected in the SFTPC gene. Two novel mutations, c.202-43 G>A and c.416 G>C, were detected among patients. The c.201+49 C>T mutation showed a significant difference with the minor allele frequency (MAF) data. There was no significant difference between the most frequent mutations in Iranian patients and those of the general population in the world. The proximity analysis showed similarity between Iranian patients and patients of the African race. We did not find any correlation between SFTPC mutations and DPLD in the patients.

Conclusion: It seems that the rs2070684 (c.201+49 C>T) mutation could be used as a specific genetic marker for distinguishing the Iranian population from other human races in the world. There was a correlation between some intronic variations and the development of disease. A new missense mutation, c.416 G>C that encodes Arg139Thr, could probably damage the protein structure and/or function and cause the signs and symptoms of DPLD.