Abstract
Serum specimens from eight females and two males representing three generations of an American Negro family exhibited an α(1)-antitrypsin phenotype that we labelled MPclifton because of its electrophoretic mobility. The family study and examination of multiple specimens from the same subject indicated that the phenotype represented an α(1)-antitrypsin allele, labelled Pi(Pclifton). The new genetic variant is not associated with deficiency of α(1)-antitrypsin or of trypsin inhibitory capacity in the serum.