HW exhibited high levels of methylation (100%, 56.5–100.0), whereas COPD-BBS and BBES showed low levels of methylation at the CpG cg23771366 located in the PRSS23 gene [0.91 (0–18.97) vs. 9.17 (0.04–99.9), respectively], indicating statistically significant differences (p = 0.011) between the two groups, with COPD-BBS demonstrating the lowest levels of methylation at cg23771366 (Figure 1). Here, PRSS23 is linked to chronic obstructive pulmonary disease.