SERPINA1 and alpha 1-antitrypsin deficiency: Although functional AAT administration can be used to treat AATD patients with emphysema (Wewers et al., 1987; Sandhaus, 2004), this augmentation treatment is shown to not improve lung function and reduce exacerbation events in AATD patients with obstructive pulmonary disease (Chapman et al., 2015; Stolk et al., 2019).