Abstract | OBJECTIVE: To investigate the association of complement C4 null genes (C4Q0, including C4AQ0 and C4BQ0) and C2 gene with systemic lupus erythematosus (SLE) in southwest Han Chinese; 136 patients with SLE and 174 matched controls were genotyped. METHODS: C4 null genes were determined by a polymerase chain reaction (PCR) procedure with sequence specific primers (PCR-SSP). The 2 bp insertion in exon 29, which was previously identified in non-Chinese populations and caused defective C4A genes, was directly typed by sequencing the whole exon 29 using exon specific primers. The exon 6 of complement C2 was also sequenced in both the patients and controls. RESULTS: The frequency of homozygous C4AQ0 allele was 12.5% (17/136) in patients with SLE compared with 1.1% (2/174) in controls (p<0.001, odds ratio (OR)=12.286, 95% confidence interval (95% CI) 2.786 to 54.170). There was no significant difference for homozygous C4BQ0 allele between patients with SLE and controls (p=0.699). Patients with the C4AQ0 gene had an increased risk of acquiring renal disorder, serositis, and anti-dsDNA antibodies compared with those without C4AQ0 (for renal disorder, p=0.018, OR=8.951, 95% CI 1.132 to 70.804; for serositis, p=0.011, OR 4.891, 95% CI 1.574 to 15.198; for anti-dsDNA, p=0.004, OR 7.630, 95%CI 1.636 to 35.584). None of the patients or controls had the 2 bp insertion in exon 29 of the C4 gene. The type I C2 deficiency was not detected in the 310 samples. CONCLUSION: It is suggested that deficiency of C4A (not due to a 2 bp insertion in exon 29), but not C4B or C2, may be a risk factor for acquiring SLE in south west Han Chinese; this results in increased risk of renal disorder, serositis, and anti-dsDNA antibodies in patients with SLE. Racial differences seem to be relevant in susceptibility to SLE
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Authors | X-Y Man, H-R Luo, X-P Li, Y-G Yao, C-Z Mao, Y-P Zhang |
Journal | Annals of the rheumatic diseases
(Ann Rheum Dis)
Vol. 62
Issue 1
Pg. 71-3
(Jan 2003)
ISSN: 0003-4967 [Print] England |
PMID | 12480675
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Chemical References |
- Complement C2
- Complement C4
- Complement C4a
- Complement C4b
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Topics |
- Adolescent
- Adult
- Aged
- Case-Control Studies
- Child
- China
(ethnology)
- Complement C2
(genetics)
- Complement C4
(genetics)
- Complement C4a
(genetics)
- Complement C4b
(genetics)
- Female
- Gene Deletion
- Gene Frequency
- Genotype
- Homozygote
- Humans
- Lupus Erythematosus, Systemic
(ethnology, genetics, pathology)
- Male
- Middle Aged
- Phenotype
- Polymerase Chain Reaction
(methods)
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