Signatures for chronic obstructive pulmonary disease (COPD) and asthma: a comparative genetic analysis.

Background: Chronic obstructive pulmonary disease (COPD) and asthma are obstructive lung diseases which progress in severity with time. Environmental causes and genetic makeup of individuals play important roles in disease manifestation. The aim of present study was to search for diagnostic/prognostic biomarkers to differentiate COPD and asthma.Materials and methods: Seven ADAM33 and two AQP5 single-nucleotide polymorphisms (SNPs) were genotyped by polymerase chain reaction-restriction fragment length polymorphism method. The association of genotypes, haplotypes and allelic combination of variants in different genes was analyzed in 194 COPD, 150 asthma patients and 220 controls.Results: The genotype frequencies of SNPs V4(C/G), T1(T/C), S2(G/C) of ADAM33 and AQP5 A/G (rs3736309) were associated with COPD and asthma (P=0.038 to P<0.001), while S1(A/G) and F+1(C/T) were associated with asthma (both P<0.001) and V1(G/T) with 20 COPD (P<0.001). The allele frequencies of V4(C/G) (both P<0.001), V1(G/T) (both P<0.05), S2(G/C) (both P<0.01) and S1(A/G) (both P<0.05) were associated with COPD and asthma, while F+1(C/T) was associated only with asthma (P=0.005). Haplotypes of ADAM33 'GGTGGGT' (P=0.027), 'CGTCGGC' (P<0.001) and AQP5 'GA' and 'AG' (both P<0.001) were significant only in COPD.Conclusion: ADAM33 F+1(C/T) variant and allele combination 'GGTGGGTGA' may be specific markers for asthma, while AQP5 'AG' appeared as a haplotype associated only with COPD. These specific genetic biomarkers may be exploited to predict individual predisposition to COPD and asthma.