Association between the CTGF -945C/G polymorphism and systemic sclerosis: a meta-analysis

Background: The -945C/G polymorphism of the connective tissue growth factor (CTGF) has been associated with systemic sclerosis, however, results were conflicted. The aim of this study was to validate the evidence for the CTGF -945C/G polymorphism and systemic sclerosis risk.

Methods: Electronic search of PubMed was conducted to select studies. Case-control studies containing available genotype frequencies of -945C/G were chosen, and odds ratio (OR) with 95% confidence interval (CI) was used to assess the strength of this association.

Results: Six published case-control studies including 3335 cases and 3589 controls were identified. The overall results suggested that the variant genotypes were not associated with the systemic sclerosis risk (OR=0.947, 95% CI: 0.792-1.132, p=0.55). The stratified analysis in Caucasian (OR=1.002, 95% CI: 0.837-1.2, p=0.788) did not suggest an association either. However, analysis in Asian (OR=0.632, 95% CI: 0.459-0.869, p=0.005) showed that CC/CG genotype greatly decreased the susceptibility of systemic sclerosis in a dominant model. Asymmetric funnel plot, the Egger's test (p=0.292), and the Begg's test (p=0.593) were all suggestive of the lack of publication bias.

Conclusion: This meta-analysis supports that CC/CG genotype greatly decreased the susceptibility of systemic sclerosis in Asian. Due to the limited samples in subpopulations, further prospective studies with larger number of participants worldwide are needed to examine the association between the CTGF -945C/G polymorphism and systemic sclerosis.