In recent years, genome-wide association studies (GWAS) have identified hundreds of genetic variants associated with COPD risk, including genes encoding matrix metalloproteinase 12 (MMP12), glutathione S-transferase, the alpha-nicotinic acetylcholine receptor, and hedgehog interacting protein (HHIP) (5, 6). Here, MMP12 is linked to chronic obstructive pulmonary disease.