Until now, multiple examples carrying dysfunctions in other protease systems have been presented to be associated with lung diseases: neutrophil elastase/α1-antitrypsin imbalance causing human emphysema (Goopts et al., 2009; Meyer and Jaspers, 2015); mouse α1-antitrypsin (serpina1) knockout leading to spontaneous emphysema (Borel et al., 2018); and chymotrypsin-like elastase 1 responsible for emphysema, proven by an antisense oligo model for the α1-antitrypsin deficiency (Joshi et al., 2018). The gene discussed is SERPINA1; the disease is pulmonary emphysema.