Screening for Homozygous and Heterozygous α1-Antitrypsin Deficiency

Homozygous and heterozygous inherited deficiencies of α₁-antitrypsin predispose to the development of pulmonary emphysema in individuals exposed to pulmonary irritants such as cigarettes, suggesting that a screening procedure and preventive medical program may be applicable. Measurement of the α₁-globulin by electrophoresis of serum on cellulose acetate correlates with the enzymatic assay of trypsin-inhibitory capacity and provides a simple screening procedure for antitrypsin deficiency. All deficient subjects had less than 0.20 gm/100 ml of α₁-globulin, suggesting that the enzymatic assay of inhibitor need be performed only on sera with 0.20 gm/100 ml or less of α₁-globulin. Surveys of normal and diseased populations by this technique reveal a 4.7% incidence of heterozygosity in a healthy industrial population, compared to an 18.1% incidence of heterozygosity in patients with emphysema. This lends further support to the contention that both homozygous and heterozygous deficiencies of antitrypsin activity are associated with the development of emphysema.