Historical role of alpha-1-antitrypsin deficiency in respiratory and hepatic complications.

Alpha-1-antitrypsin (AAT) deficiency is a heritable disease that is commonly associated with complications in the respiratory and hepatic systems. AAT acts as a regulatory enzyme that primarily inhibits neutrophil elastase activity thus protecting tissues from proteolytic damage after inflammation. This paper provides a historical review of the discovery, classification, phenotypic expression, and treatment of AAT deficiency. While its pattern of inheritance has been long understood, the underlying mechanism between AAT deficiency and related diseases remains to be elucidated. Most commonly, AAT deficiency is associated with the development of emphysema in the lungs as well as various liver injuries. Cigarette smoke has been shown to be particularly detrimental in AAT deficient individuals during the development of lung disease. Therefore, understanding familial history may be beneficial when educating patients regarding lifestyle choices. While numerous AAT deficient phenotypes exist in the human populations, only specific variants have been proven to markedly predispose individuals to lung and liver disorders. The exact relationship between AAT levels and the aforementioned diseases is an essential area of further research. It is imperative that clinicians and researchers alike strive to standardize diagnostic criteria and develop safe and effective therapies for this genetic disease.