In a case-control analysis of COPD susceptibility limited to cases with densitometric upper-lobe-predominant cases, the EPHX1 His139Arg single-nucleotide polymorphism was associated with COPD (p = 0.005).
Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was performed to find mEH polymorphism in exon 3 (Tyr113-->His), exon 4 (His139-->Arg) and GSTP1 polymorphism in exon 5 (Ile105-->Val) in 100 COPD patients and 100 age- and sex-matched healthy controls.