Alpha-1-antitrypsin deficiency: a review; 1963-1975.

Alpha-1-antitrypsin (A1AT) deficiency originally was recognized as a biochemical abnormality in patients with pulmonary emphysema. Studies of the protein nature of A1AT during attempts to help explain the disease, led to the recognition of a protein polymorphism which expressed itself in several different phenotypes. As investigative work progressed, the spectrum of diseases associated with a deficiency of A1AT increased. Methods for determination of quantitative levels have been developed but these have proved lacking for the discrimination of the various phenotypes, for which specialized testing is necessary. Of the clinical states associated with deficiencies of A1AT, pulmonary emphysema and hepatic disease are the best defined. Pathogenetic implications, however, remain elusive. As a consequence, preventive aspects are debatable and the usefulness of the determination of A1AT levels as screening measures is controversial.