title: Structural heterogeneity of C2 Complement protein and its genetic variants in man: a new polymorphism of the HLA region.
abstract: A zymogram method, following thin-layer isoelectric focusing in a polyacrylamide gel, allows resolution of the lytic activity of serum C2 complement protein in a spectrum of molecular forms. This spectrum is characteristic in each of the species studied (man, rhesus monkey, guinea pig, and hamster). Moreover, two different alternative patterns are observed in man: each of the six major lytic bands characteristic of the most common pattern (herein designated C2(1) is duplicated in the least common pattern (C2(2-1), with an additional band displaced cathodally by not more than 0.04 pH unit. Distribution of phenotypes C2(1) and C2(2-1) in a Caucasion population is in agreement with the hypothesis that they are controlled by two alleles, C2(1) and C2(2), with frequencies 0.96 and 0.04 +/- 0.01. Segregation studies show that the two alleles are codominant and identify a locus in the HLA region. No recombinants with HLA-B were detected among 27 informative meioses, generating a cumulative lod score of 6.321 at equals 0. These findings suggest that the individuals with the C2-deficient trait might be interpreted as homozygotes for a third and rarest amorph C2 degrees of the same locus.
mesh_terms: D000818:Animals; D003175:Complement C2; D003165:Complement System Proteins; D005260:Female; D008040:Genetic Linkage; D014644:Genetic Variation; D006680:HLA Antigens; D006649:Histocompatibility Antigens; D006801:Humans; D007525:Isoelectric Focusing; D008297:Male; D010641:Phenotype; D011110:Polymorphism, Genetic; D013045:Species Specificity
chemical_list: D003175:Complement C2; D006680:HLA Antigens; D006649:Histocompatibility Antigens; D003165:Complement System Proteins
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