Abstract
The results of Pi typing 5237 unrelated Caucasians are presented, together with the phenotypes of 2203 children from 1156 families. The estimate of the gene frequencies in the United Kingdom are Pi-M equal 0-9303, Pi-S equal 0-050, Pi-Z equal 0-0141, Pi-minus equal 0-0015, Pi-V equal 0-0004. Evidence for three new alleles, Pi-W2, Pi-Y2 is presented. The results of twin studies and quantitative studies are discussed.