Properdin factor B (Bf) polymorphism in Norway

Complement polymorphism in Greece

The polymorphisms of the complement components C2, C3, C4 and BF have been studied in a sample of 166 unrelated individuals from Northern Greece. The C3*F and BF*F allele frequencies of Greeks are within the range of frequencies reported from Europe. A single individual with a rare heterozygote variant C2C/C2A was found in Greeks. This C2*A allele was found for the first time in European Caucasoids. For the C4 system six different alleles were found at both C4A and C4B loci. There were a low frequency of the null alleles at the C4A locus and a relatively high incidence of gene duplications in this system.

Family studies in Bechterew's syndrome (ankylosing spondylitis) III. Genetics

The results of segregation analyses in 75 families where the proband had ankylosing spondylitis, are presented. Of the 278 adult, living first degree relatives, approximately 85% cooperated in the study. Clinical and radiographical examinations were performed and HLA typing was conducted. The results were in agreement with our hypothesis that ankylosing spondylitis is part of a syndrome where different genetic factors interact. Such known factors are HLA B27 associated disease susceptibility, susceptibility to psoriatic arthropathy and susceptibility to entero-arthropathy. Radiographical sacro-iliitis was restricted to HLA B27 positive relatives, and was more frequently found in relatives to probands with psoriasis than in relatives to probands without psoriasis. Environmental factors (intestinal bacteria) are known to trigger the disease at least in some persons, and we have postulated that all or most of them have the predisposition to develop disease. Thus, the syndrome has a multifactorial etiology. The phenotypic expressions of the different genetic predispositions involved, include sacro-iliitis, psoriasis, acute anterior uveitis, peripheral arthropathy and inflammatory bowel disease. We suggest the descriptive name HEREDITARY MULTIFOCAL RELAPSING INFLAMMATION (HEMRI) for this syndrome. Ankylosing spondylitis, psoriatic arthropathy and entero-arthropathy may be regarded as clinical sub-types of the syndrome.

Properdin factor B polymorphism in continental Italy and Sardinia

A sample of healthy unrelated individuals (882 from Continental Italy and Sicily, and 139 from Sardinia) were typed for HLA and Bf polymorphisms. Bf gene frequencies in Continental Italy and Sicily show an intermediate position among European populations, with Lapps on one side and Basques on the other side; while a very peculiar pattern is observed among Sardinians, with an impressive similarity with French Basques and with the highest F1 gene frequency so far observed. The HLA:Bf gametic associations in Italy and Sardinia are also reported, which confirm the different ethnic background of these populations.

Genetic linkage between Bf S0.7 (Bf S1) and HLA-Bw50

Two hundred and one unrelated French Basque individuals were studied for HLA-A, B, C, DR and Bf polymorphisms. The results show that the Bf S0.7 (Bf S1) variant, which is known to be associated with HLA-Bw21, presents a highly significant linkage disequilibrium with a subtypic specificity, i.e., Bw50 (delta = 0.0123, delta S=100%, P less than 10(-8)). As neither Bf S0.7 variant nor Bw50 antigen is found in Mongoloid populations, it is suggested that in evolutionary terms, the Bf S0.7 mutation is a more recent event than the HLA-Bw21 split.

Strong linkage disequilibrium between HLA-Dw2 and and BfS in multiple sclerosis and in the normal population

An increased frequency of the S allele of Properdin factor B (BfS) was found amongst 162 patients with multiple sclerosis (MS) compared with 470 normal controls. This increase was shown to be due to a strong linkage disequilibrium (LD) between BfS and HLA-Dw2 in 77 patients typed for both systems (delta = 3.84%, P = .0002). The same LD was demonstrated amongst 100 normal controls (delta = 2.24%, P = .0049) and 31 patients with idiopathic demyelination of the peripheral nervous system (IDPN). A total of 70 haplotypes with HLA-Dw2 were encountered (40 MS, seven IDPN and 23 normal controls) and all contained BfS. In the MS patient group, a much weaker association was noted between BfS and HLA-B7 suggesting either that the Bf locus is musch closer to the HLA-D than the HLA-B locus or (and) that HLA-D and Bf products selectively interact (perhaps on the surface of B lymphocytes) with evolutionary advantage or disadvantage resulting from certain allelic combinations. Strong associations between BfS1 and HLA-Bw21 (P = .0000) and BfF1 and HLA-B18 (P = .0001), both previously reported, were confirmed in the current study. No increase in the frequency of a glyoxalase (GLO) allele was found amongst the MS patients and no LD was encountered between HLA-Dw2 and a GLO allele. The possibility that the HLA-Dw2, BfS disequilibrium has resulted from a selective advantage conferred on the general community but at the expense of increasing susceptibility to MS should be considered.

Properdin factor B-polymorphism. An indication for the existence of a Bf O-allele

The polymorphism of the properdin factor B (Bf, C3-proactivator, GBG = glycin-rich-beta-glycoprotein) has been investigated by high voltage agarose gel immunofixation electrophoresis in 1115 unrelated persons from Southern Germany. Seven phenotypes were observed; the allele frequencies were calculated as BfS = 0.8094, BfF = 0.1790, BfSI = 0.0094, BfFI = 0.0022. A study of 94 parents with 98 children and 420 mother-child combinations showed no deviation from the assumed autosomal codominant mode of inheritance. In one additional family the findings suggested the existence of a silent allele at the Bf-locus.

Population genetic data on properdin factor B (Bf) in northern Germany

Properdin factor B phenotypes were determined in 1,112 unrelated individuals and in 151 mother/child combinations from Northern Germany. Gene frequencies were : F = 0.1960, S= 0.7905, F1 = 0.0072, S1 = 0.0063. The data of the mother/child combinations are in full accordance with the postulated gene model.