An improved method for the identification of Gc1 subtypes (group-specific component) by isoelectric focusing.

The occurrence of common subtypes of the Gc1 gene in a German population (n = 261) was investigated by isoelectric focusing on thin layers of polyacrylamide in the pH range 4-6. Six common phenotypes designated Gc 1S, 1F, 1F-1S, 2-1S, 2-1F, and 2 are considered as gene products of three common alleles with the following frequencies: Gc1S=O.603, Gc1F=0.125, and Gc2=0.272. The sum of the allele frequencies of Gc1S and Gc1F corresponds with that of the 'old' Gc allele. Family investigation are in agreement with an autosomal codominant way of inheritance. the method employed provides an identification of the subtypes within 4 h without using anti-Gc-serum for immunoprecipitation.