SERPINA1 and chronic obstructive pulmonary disease: Genome wide association studies (GWAS) have found several genetic polymorphisms that are associated with COPD or lung function decline, including polymorphisms in or near genes encoding matrix metalloproteinase 12, nicotinic acetylcholine receptor, hedgehog interacting protein, glutathione S-transferase, C-terminal domain–containing protein [5–9] and the antiprotease alpha-1-antitrypsin [10].