Properdin factor B (glycine-rich beta-glycoprotein or C3 proactivator)-polymorphism: genetic and biochemical aspects. First application to paternity cases.

Determination of genetic properdin factor B(Bf) polymorphism was carried out in immunofixation electrophoresis. Genetics of factor B were also studied after ageing, conversion with cobra venom and neuraminidase. In population studies the distribution of factor B in a West German population of 1245 non-related individuals was found to be: Bf F 2.73%, Bf FS 28.43%, Bf S 65.38%. Rare phenotypes (F 1F,F 1S, FS 1, SS 1) were seen in 3.46%. In addition a new variant, designated F1.6S, was observed. The application of factor B polymorphism to 68 paternity cases is discussed.