Polymorphism of the complement component C6 in Japanese.

Genetic polymorphism of human C6 was investigated in Japanese using isoelectric focusing and a specific haemolytic overlay method. Three common and six rare allotypes were identified. Five of these nine allotypes were reference-typed by the International Reference Laboratory. Five of the six rare allotypes were considered to be new. The allele frequencies were estimated in the population study as follows: C6 A 0.427, C6 B 0.483, C6 B2 0.076, and the rare alleles (A3, A21, M1, M2, B3, and B4) 0.014. Inheritance of the three common and the two rare (A3 and M1) allotypes was demonstrated in the family study. The patterns obtained by the pretreatment with neuraminidase are presented.