C-reactive protein gene polymorphisms (rs1205) in Asian Indian patients with Takayasu arteritis: Associations and phenotype correlations.

Background/purpose: Normal C-reactive protein (CRP) in active Takayasu arteritis (TA) is a dilemma. We attempted to validate our pilot study finding of rs1205 in CRP gene being protective against TA.

Methods: Genomic DNA of 104 patients and 185 sex-matched healthy controls were genotyped for rs1205 by Taqman assay. Clinical details, demography, angiographic and activity scores (Indian Takayasu arteritis score 2010) were recorded prospectively at baseline and during follow-up visits for 12 months. Minor allele frequency (MAF) and genotype distribution between patients and controls as well as patient subgroups were compared using χ test with Bonferroni correction (p ) and logistic regression was performed to determine independent associations.

Results: The majority of patients (n = 84) and controls (n = 166) were females. MAF of T allele of rs1205 was less frequent in patients (27%) as compared to controls (37.6%), P = 0.013, p = 0.026 with an odds ratio of 0.632 irrespective of gender. Frequency of CC genotype was higher in cases (53.8%) than controls (37.3%), P = 0.006, p = 0.018. A dominant model of genotype-phenotype association revealed CC to be associated with more frequent coronary arterial and ascending aorta involvement than the other genotypes clubbed together (P = 0.01 and P = 0.014, respectively). Blunted CRP response seems to be less frequent in patients with CC genotype (P = 0.064).

Conclusion: T allele of rs1205 in CRP gene was less frequent in TA. CC genotype was associated with involvement of coronary arteries and ascending aorta. CC genotype was less commonly associated with blunted CRP response (CT + TT > CC).