Alpha-1 antitrypsin deficiency (AATD) is a relatively rare genetic disorder, inherited in an autosomal codominant manner, that results in reduced serum AAT concentrations, with a consequent reduction in antielastase activity in the lungs, as well as an increased risk of diseases such as pulmonary emphysema, liver cirrhosis, and necrotizing panniculitis. This evidence concerns the gene SERPINA1 and pulmonary emphysema.