title: Association of vitamin D receptor gene polymorphisms and serum 25-hydroxyvitamin D levels with Crohn's disease in Chinese patients.
abstract: OBJECTIVE
  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 (β = -0.829, P < 0.001), platelet count (β = -0.253, P < 0.001) and neutrophil percentage (β = -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.
authors.affiliation: Department of Gastroenterology, The Second Affiliated Hospital of Wenzhou Medical University, Wenzhou, China.
authors.forename: Sheng-long
authors.initials: SL
authors.lastname: Xia
authors.affiliation: Department of Gastroenterology, The Second Affiliated Hospital of Wenzhou Medical University, Wenzhou, China.
authors.forename: Xin-xin
authors.initials: XX
authors.lastname: Lin
authors.affiliation: Department of Gastroenterology, The Second Affiliated Hospital of Wenzhou Medical University, Wenzhou, China.
authors.forename: Mao-dong
authors.initials: MD
authors.lastname: Guo
authors.affiliation: Department of Gastroenterology, The Second Affiliated Hospital of Wenzhou Medical University, Wenzhou, China.
authors.forename: Da-guan
authors.initials: DG
authors.lastname: Zhang
authors.affiliation: Department of Gastroenterology, The Second Affiliated Hospital of Wenzhou Medical University, Wenzhou, China.
authors.forename: Shu-zi
authors.initials: SZ
authors.lastname: Zheng
authors.affiliation: Department of Gastroenterology, The Wenzhou Central Hospital, Wenzhou, China.
authors.forename: Li-jia
authors.initials: LJ
authors.lastname: Jiang
authors.affiliation: Department of Gastroenterology, The Wenzhou Central Hospital, Wenzhou, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Jin
authors.affiliation: Department of Gastroenterology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China.
authors.forename: Xiu-qing
authors.initials: XQ
authors.lastname: Lin
authors.affiliation: Department of Gastroenterology, The Wenzhou Renmin Hospital, Wenzhou, China.
authors.forename: Ran
authors.initials: R
authors.lastname: Ding
authors.affiliation: Department of Gastroenterology, The Second Affiliated Hospital of Wenzhou Medical University, Wenzhou, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Jiang
mesh_terms: D000328:Adult; D044466:Asian People / Q000235:genetics*; D003424:Crohn Disease / Q000097:blood* / Q000209:etiology / Q000235:genetics*; D005260:Female; D056726:Genetic Association Studies; D006801:Humans; D008297:Male; D009154:Mutation; D011110:Polymorphism, Genetic; D018167:Receptors, Calcitriol / Q000235:genetics*; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000150:complications; D055815:Young Adult
chemical_list: D018167:Receptors, Calcitriol; D014807:Vitamin D; C104450:25-hydroxyvitamin D
keywords: 25-hydroxyvitamin D; Crohn's disease; polymorphism; vitamin D receptor