Association of angiotensin-1-converting enzyme gene variations with silicosis predisposition.

Interactions between several genes and environmental factors occur in silicosis and other dust-mediated pulmonary fibrosis. It has been suggested that several genes play role in individual susceptibility to silicosis. The aim of this study was to determine the angiotensin-1-converting enzyme (ACE) gene (I/D) variations in patients with silicosis and healthy controls in Iranian Kurdish population. Forty-one male workers with silicosis and 41 healthy male controls were entered in the study. Polymerase chain reaction (PCR) method was carried out for allele and genotype typing. Our finding showed that the frequencies of D and I alleles were 0.65 and 0.35 in the silicotic patients compared to 0.52 and 0.48 in the controls. The frequencies of ACE D/D, D/I, and I/I genotypes were 15 (36.59%), 23 (56.1%), and 3 (7.31%) in patients, and 14 (34.15%), 15 (36.59%), and 12 (29.27%) in the controls, respectively. The results indicate that the frequency of ACE D/D+D/I genotypes were higher in the patients group (92.7% vs. 70.73%) (OR: 5.24, 95% CI: 1.35-20.30, P = 0.01). Also, ACE I/I genotype frequency was lower in patients (7.32% vs. 29.27%) (OR: 0.19, 95% CI: 0.04-0.73, P = 0.01). It can be concluded that ACE D/D and I/D genotypes may play a role in the susceptibility to silicosis; on the contrary, ACE I/I genotype may have protective effect.