Allotypic variants of human C3 and properdin factor B in two French populations Normans and Basques.

Human Properdin factor B and C3 polymorphisms are of a real usefulness as genetic markers for population studies. In addition, they are more and more used for the determination of paternity cases. The present communication will be about Bf and C3 allele frequencies in two locally populations of France, Normandy and Western Pyrenees (Basques), The corresponding allele frequencies are as follows, for Normans : Bf(S) = 0.7422, Bf(F) = 0.2285, Bf(F1) = 0.0205, Bf(SO.7) = 0.0088; CsS = 0.788, C3F = 0.204, C3Srare = 0.004, C3Frare =0.004; and for Basques : BfS = 0.5625, BfF = 0.305, BfF1 = 0.1235, BfSO.7 = 0.0075; C3S = 0.7075 and C3F - 0.2925. French Basques are characterized by unusual allele frequencies in European Caucasoid populations for Bf as for C3 genes. A very high incidence of BfF1 allele is reported (BfF1 = 0.125), as previously observed [7, 17].