SERPINA1 and hyperinsulinemic hypoglycemia, familial, 4: Nevertheless, lung disease due to AAT deficiency can be prevented by protein augmentation therapy (American Thoracic/European Respiratory Society, 2003; Wewers et al, 1987) or replenishment of the deficient gene product via AAV-mediated muscle-directed gene therapy (Brantly et al, 2009; Flotte et al, 2004).