Aim: To validate novel single nucleotide polymorphisms (SNPs) in Greek patients with Crohn's disease (CD).
Methods: A total of 120 patients with CD, 85 patients with UC, and 100 unrelated healthy controls were genotyped. Genotyping was performed by allele-specific PCR or by PCR-RFLP analysis.
Results: Our results showed that the 1672T and -207C alleles were obviously over-represented in CD patients only (P<0.01 and P<0.05, respectively) compared to the control population. The G113A polymorphism was completely absent in our studied population. The odds ratio for the carriage of the TC haplotype was 2.21 for CD patients as compared with controls. Additionally, the frequency of the TC haplotype was increased in patients with ileocolitis or colitis, and was mainly associated with the fibrostenotic phenotype of the disease. Furthermore, when the TC haplotype was compared jointly with the carriage of at least one mutation of the NOD2/CARD15 gene, there was an increased risk for CD, but not for UC, compared to controls. Regarding the location of the disease, the concomitant presence of the TC haplotype and NOD2/CARD15 mutations was mainly associated with ileocolitis or ileitis.
Conclusion: Collectively, our results suggest that the 1672T variant of the OCTN1 gene and the -207C variant of the OCTN2 gene represent risk factors for CD in the Greek population.