C1R subcomponent polymorphism in Japanese: description of a new allele.

The polymorphism of C1R was investigated in 570 unrelated Japanese individuals using isoelectric focusing and immunoblotting. A total of 11 different C1R phenotypes including a new pattern designated C1R 11-1 were observed. The allele frequencies were C1R1 = 0.4561, C1R2 = 0.3377, C1R5 = 0.1956, C1R8 = 0.0088 and C1RR (C1R9 and C1R11) = 0.0018. The population data fitted the Hardy-Weinberg equilibrium. The C1R polymorphism in Japanese was shown to be controlled by 3 common alleles, C1R1, C1R2 and C1R5, as compared to Caucasians where only the former 2 are present commonly. This complement system can be a useful genetic marker for anthropological studies.