α1-Antitrypsin: Common Subtypes of Pi M

Abstract

More than 20 different alleles are so far known at the Pi locus, corresponding to a total variant phenotype frequency of about 10% in most western Europeans. The common phenotype Pi M constitutes the remaining major group. Now it has been possible to identify three subtypes M₁, M₁M₂ and M₂, corresponding to the gene products of two common alleles Pi^M1 and Pi^M2, segregating as autosomal codominant alleles. Preliminary gene frequencies are reported for eight populations, the Pi^M2 frequency varying from 0.20 in Maris (USSR) to 0.02 in Bantus (Kenya).