ARNT and chronic obstructive pulmonary disease: When the association of haplotypes was carried out, we found nine different combinations of SNPs associated with COPD-S in the genes: ARNTL (rs10741616-rs7126796), ARNTL2 (rs11048977-rs1037924-rs17497857-rs7138982), CYP19A1 (rs10046-rs700519-rs6493489-rs2899472-rs2414095-rs700518), ARNT2 (rs1374213-rs3901896-rs7168908-rs2278709), CYP46A1 (rs3742377-rs943881-rs1951576-rs12435918-rs2146238), ARNT (rs10847-rs11552229-rs2228099), and MGST3 (rs8133-rs4147611) (Table 4).