Increased D allele frequency of the angiotensin-converting enzyme gene in pulmonary fibrosis

An insertion/deletion (I/D) polymorphism of the angiotensin-converting enzy me has previously been studied extensively in relationship to cardiovascula r and renal disease. The deletion/deletion (D/D) genotype is associated wit h a pool outcome in immunoglobulin (Igf A nephropathy. However, the associa tion of this genetic marker in cardiovascular and renal disease has generat ed controversy, with the exception of the rate of progression and therapeut ic responsiveness in IgA nephropathy. Many of the same cytokines and polype ptide mediators involved in fibrosis of the cardiovascular and renal system s have been shown to be involved in pulmonary fibrosis. We examined the I/D polymorphism of the angiotensin-converting enzyme in a group of 24 patents with interstitial pneumonia and moderate to severe pulmonary fibrosis defi ned by radiographic studies, pulmonary function tests, and histologic findi ngs. The incidence of the D allele in this study population was 69.0%, whic h is approximately 15.0% higher than the incidence in the general populatio n of 54.0%. The incidence of the D/D genotype was 42.0%, which is approxima tely 11.0% greater than that in the general population (31.0%). The distrib ution of the D/D, I/D, and insertion/insertion genotypes of these 24 patien ts was not significantly different from that of historical controls (P = .1 ; chi (2) test); there were marginally significantly more D alleles among t he 48 observed alleles than would be expected (P = .04). Copyright (C) 2001 by W.B. Saunders Company.