The results of a neonatal screening programme for alpha-1-antitrypsin deficiency are presented. Cord blood samples with an alpha-1-antitrypsin concentration below 1.628 mg/ml, as measured by an enzyme-linked immunosorbent assay method, were phenotyped by isoelectric focusing in polyacrylamide gels. Abnormal phenotypes were found in 51% of this group as compared with 11.3% in a control group (P much less than 0.0001). Twenty subjects detected by the initial quantitative alpha-1-antitrypsin determination had a highly pathogenic phenotype (PiZZ, PiSS, PiSZ). In the control group only moderately affected individuals were found (PiMS, PiMZ).
