SERPINA1 and alpha 1-antitrypsin deficiency: In AATD, current treatment strategies are employing this technology to simultaneously silence the Z allele and express the M allele of SERPINA1. 18,19 This strategy would prevent expression of misfolded AAT proteins responsible for inducing liver disease, and allow normal AAT proteins to be secreted into the circulatory system at normal levels and alleviate lung disease.