Association of vitamin D receptor gene polymorphisms with the susceptibility to ulcerative colitis in patients from Southeast China

Abstract

The association studies from different ethnic groups showed that vitamin D receptor (VDR) gene polymorphisms might be connected with the susceptibility to ulcerative colitis (UC); however, the conclusions were less consistent. Our study aimed to analyze the associations of UC with common mutations of VDR in Chinese patients. A total of 382 UC patients and 489 healthy controls were recruited. The genotypes of VDR FokI (rs2228570), BsmI (rs1544410), ApaI (rs7975232) and TaqI (rs731236) were examined by SNaPshot assays. Haplotype analysis was performed in all study subjects. After Bonferroni correction, the mutant alleles and genotypes of VDR FokI, BsmI, ApaI and TaqI did not statistically differ between UC patients and the controls (all p > 0.0125). However, the mutant allele C and genotype TC + CC of FokI gene were significantly increased in patients with mild and moderate UC compared to those with severe UC (C allele: 54.1% versus 39.3%, OR = 1.83, 95% CI: 1.21–2.75, p = 0.004; TC + CC genotype: 81.6% versus 57.1%, OR = 3.32, 95% CI: 1.83–6.06, p < 0.001, respectively). Haplotype analysis showed that the VDR BsmI, ApaI and TaqI polymorphic loci were in a strong linkage disequilibrium. Furthermore, the frequency of AAC haplotype was statistically lower in UC patients than that in the controls (3.8 versus 5.9%, OR = 0.63, 95% CI: 0.39–1.01, p = 0.039). In conclusion, the mutation of FokI gene influenced severity of the disease in UC patients. Moreover, the AAC haplotype formed by the VDR BsmI, ApaI and TaqI gene might engender a reduced risk of UC attack.