Objective: To investigate the possible implication of CD24 gene in the genetic predisposition to giant cell arteritis (GCA).
Methods: A total of 120 patients diagnosed with biopsy-proven GCA and 195 ethnically matched controls from the same region were studied. Two putative functional polymorphisms, a C to T coding polymorphism (rs8734) and a TG deletion in the 3' untranslated region (rs3838646) were used as CD24 genetic markers and genotyped using a Taqman 5' allelic discrimination assay.
Results: The 2 genetic variants showed statistically significant differences between patients with GCA and controls. The strongest association was observed for the rs3838646 TG/del polymorphism, conferring on the "del" allele an increased risk of GCA genetic susceptibility (odds ratio 1.94, 95% confidence interval 1.15-3.27, p = 0.01). In addition, genotypes carrying the rs3838646 "del" allele showed an increased frequency among GCA patients compared to controls (OR 2.31, 95% CI 1.30-4.1, p = 0.003). For the rs8743, an increased frequency of Val/Val homozygous individuals in patients with GCA compared to controls (OR 6.08, 95% CI 1.50-24.63, p = 0.001) was observed. A high degree of linkage disequilibrium was estimated between the 2 polymorphisms (D' = 0.7) and the C/del haplotype was associated with an increased risk of GCA susceptibility (OR 2.10, 95% CI 1.23-3.60, p = 0.005), whereas the C/TG haplotype showed a protective effect (OR 0.63, 95% CI 0.45-0.87, p = 0.005).
Conclusion: Our results suggest a potential role for the CD24 gene in the susceptibility to GCA in our population.