Human complementary component C?3

Abstract

Results obtained so far on the C3 polymorphism suggest that the system should be a valuable marker in population studies. The instability of the complement component C3 may, however, cause some practical problems in population genetic fieldwork, since a certain fraction of serum samples may be difficult to type with certainity due to storage alterations. Studies of the conversion rate and the concentration of C3 have shown that there is no significant difference between the phenotypes. And furthermore, the fact that there is good agreement with the Hardy-Weinberg distribution indicates that the conversion has had no appreciable selective effect on the phenotype distribution (Brönnestam et al., 1971).

C3 Polymorphism in Greece

“…There was no significant heterogeneity between the nine areas. The C3 frequencies observed in the Greeks are similar to those found in other Caucasian populations [5]. The gene frequencies (C3F = 0.271) obtained by Tsiakalos et al [6] from a continental sam ple of 113 Greeks living in West Germany are in accordance with the frequencies of our material from Epirus, which belongs to continental Greece.…”

“…The frequencies of the two codomi nant autosomal alleles, C3S and C3F, which determine the three common pheno types of C3 (S, FS, F), are about 0.8 and 0.2, respectively, in most Caucasian popu lations [5]. A total number of 24 rare var iants have been described by different au thors [2,4].…”

Genetic Variants of Human C3 and Properdin Factor B in a Population from Tunisia

“…A lot of studies have been performed concerning the distri bution of phenotypes and allele frequencies in various populations of the world. They are, up to now, relatively numerous for C3 [Seth and Seth, 1976] as compared to the still few for factor B [Benkmann et al, 1980]. The present report describes a study of C3 and factor B polymorphism in a pop ulation from Tunisia.…”

C3, BF and C4 Polymorphisms in Tunisians

“…The frequencies of the common C3 al leles show a considerable variability in various populations as previously re ported [13][14][15][16]. The frequency at the C3*F allele in Tunisians is low compared to that in other populations.…”