Association of vitamin D receptor gene polymorphisms and serum 25-hydroxyvitamin D levels with Crohn's disease in Chinese patients.
Xia, Sheng-long; Lin, Xin-xin; Guo, Mao-dong; Zhang, Da-guan; Zheng, Shu-zi; Jiang, Li-jia; Jin, Jie; Lin, Xiu-qing; Ding, Ran; Jiang, Yi
[Miscellaneous Article]
Journal of Gastroenterology & Hepatology.
31(4):795-801, April 2016.
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Background and Aim: The vitamin D receptor (VDR) regulates immune responses and inflammation through binding with 1,25-dihydroxyvitamin D, the active form of vitamin D. The serum 25-hydroxyvitamin D (25(OH)D) level clinically reflects vitamin D status in the human body. We investigated the association of VDR polymorphisms and 25(OH)D levels in Chinese patients with Crohn's disease (CD).
Methods: Vitamin D receptor polymorphisms (FokI, BsmI, ApaI, and TaqI) were genotyped by SNaPshot. Serum 25(OH)D levels were measured by electro-chemiluminescence immunoassay.
Results: A total of 297 patients with CD and 446 controls were recruited. Compared with controls, mutant alleles and genotypes of BsmI and TaqI were less prevalent in patients with CD (all P < 0.05/4 = 0.0125). The AAC haplotype formed by BsmI, ApaI, and TaqI was also less prevalent in patients with CD (P = 0.004). Furthermore, 124 patients and 188 controls were randomly selected for measurements of 25(OH)D levels. Average 25(OH)D level was lower in patients with CD than in controls (15.46 /- 8.11 vs 21.64 /- 9.45 ng/mL, P < 0.001) and negatively linked to CD activity index ([beta] = -0.829, P < 0.001), platelet count ([beta] = -0.253, P < 0.001) and neutrophil percentage ([beta] = -0.136, P = 0.005) in patients with CD. The ApaI mutant genotype and vitamin D deficiency (<20 ng/mL) were independently associated with CD (P = 0.009, P < 0.001, respectively). In patients with CD, vitamin D deficiency interacted with FokI, ApaI, and TaqI mutant genotypes (P = 0.027, P = 0.024, and P = 0.040, respectively).
Conclusions: Vitamin D receptor (BsmI, ApaI, and TaqI) mutations and lower 25(OH)D levels are associated with CD in Chinese patients. Moreover, VDR (FokI, ApaI, and TaqI) mutations and vitamin D deficiency may have a combined impact on CD.
(C) 2016 John Wiley & Sons, Ltd