SERPINA1 and chronic obstructive pulmonary disease: Of note, CpG site cg02181506 in the SERPINA1 gene on chromosome 14 was top ranked in unadjusted analyses (hypomethylation associated with COPD) (p-value = 7.3 × 10−22), second ranked in the adjusted analysis (FDR-corrected p-value = 3.4 × 10−10), and replicated in the EOCOPD cohort (p-value = 5.1 × 10−4) in the unadjusted analysis.