Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0042384 (vasculitis)
 20,525 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The third component of complement (C3) exists in two main allotypic forms, C3S and C3F, distinguished at the DNA level by a single base change. An increased frequency of the rarer C3F allele has been reported in patients with the autoantibody nephritic factor and in several other autoimmune conditions such as rheumatoid arthritis and IgA nephropathy. Studies of the immunogenetic factors predisposing to the development of systemic vasculitis have produced conflicting results and no major genetic predisposing factors have been identified. We have studied the C3S/F polymorphism in 63 patients with systemic vasculitis using DNA allotyping by the amplification refractory mutation system, a modification of the polymerase chain reaction. The allele frequency in these patients was C3S 0.71, C3F 0.29 (expected C3S 0.8, C3F 0.19; chi-squared = 5.1, P < 0.025), with the average relative risk for the development of systemic vasculitis associated with the presence of a C3F allele being 2.6. Moreover, there was a marked excess of C3FF homozygotes (11/63, [17.5%], versus 4% expected: chi-squared = 9.5, p < 0.01). The average relative risk for the development of systemic vasculitis in C3F homozygotes was 5.1, indicating a gene dosage effect. These data indicate that the C3F allele is associated with a predisposition to the development of systemic vasculitis and that C3F homozygotes are at particularly high risk. This association is the strongest genetic factor reported so far for this group of diseases.
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PMID:Molecular analysis of C3 allotypes in patients with systemic vasculitis. 787 Mar 43

The third component of complement (C3) exists in two main allotypic forms, C3S and C3F, which can be distinguished at the molecular level using a variation of the polymerase chain reaction. An increased frequency of the C3F allele has been noted in a number of autoimmune and inflammatory conditions affecting the kidney, including systemic vasculitis, IgA nephropathy, and type II mesangiocapillary nephritis. Recently, in an unrelated study, we found (with small numbers) an increased incidence of graft loss associated with the presence of the C3F allele. To further assess this, we analyzed the S/F polymorphism in 183 donor-recipient pairs of patients undergoing renal transplantation. Forty-one of 183 grafts were lost, but graft loss was not associated with the C3F allele over 14-month follow-up. However, the presence of the C3F allele predicted an increased risk of graft dysfunction (defined as serum creatinine > 150 mumol/L): 61/105 versus 36/78, with a relative risk of 1.4 (P < 0.05). The C3F allele predisposed toward graft dysfunction when present in either donor or recipient. The presence of two C3F alleles gave a relative risk for graft dysfunction of 1.8, suggesting a dose-dependent effect, although numbers were small. The presence of the C3F allele was not significantly correlated with the number of rejection episodes, serum creatinine, or duration of primary nonfunction. These findings suggest that C3F may be a susceptibility allele for allograft injury. Possible mechanisms for this association are discussed.
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PMID:Molecular analysis of C3 allotypes related to transplant outcome in human renal allografts. 852 32

In ANCA-associated small vessel vasculitis few genetic factors have proven to be of importance for disease susceptibility, an exception being deficiency of alpha1-anti-trypsin, the main inhibitor of proteinase 3 (PR3). Alerted by our finding that myeloperoxidase has affinity for C3, and the finding of an increased frequency of the C3F allele in systemic vasculitis in a British cohort, we examined polymorphism of C3 and C4 in patients with ANCA+ small vessel vasculitis. After identification of all patients at our department with a positive ANCA test during the period 1991-95 and a diagnosis of small vessel vasculitis, blood samples were collected after informed consent. The 67 included patients were grouped according to ANCA serology and disease phenotype using the Chapel Hill nomenclature. The gene frequency of C3F was found to be increased (0. 32) compared with controls (0.20; P < 0.05) in the PR3-ANCA+ subgroup. The frequency of C4A3 was increased in the group as a whole, but no increase of C4 null alleles was seen. The findings imply a role for the complement system in the pathogenesis of ANCA-associated small vessel vasculitis.
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PMID:C3 and C4 allotypes in anti-neutrophil cytoplasmic autoantibody (ANCA)-positive vasculitis. 1033 34