title: Vitamin D Deficiency in Uygurs and Kazaks Is Associated with Polymorphisms in CYP2R1 and DHCR7/NADSYN1 Genes.
abstract: BACKGROUND
  Our study is aimed to 1) clarify the vitamin D status in Uygur and Kazak ethnic populations and 2) elucidate the relationship between 14 SNPs (in 5 vitamin D-related genes) and vitamin D deficiency in these 2 ethnic populations.
  
  
  METHODS
  A multistage-cluster sampling survey was carried out for residents with Uygur or Kazak ethnicity in Xinjiang, China. Anthropometric measurements were taken and the concentrations of 25OHD were measured. Fourteen common variants in VDR, GC, CYP2R1, CYP27B1, and DHCR7/NADSYN1 were genotyped by using multiple SNaPshot assay. Logistic regression analysis was performed to identify the possible risk factors for vitamin D deficiency, after adjusting for several environmental and biological factors. The pattern of SNP associations was distinct between Uygurs and Kazaks.
  
  
  RESULTS
  Anthropometric measurements and the concentrations of 25OHD were obtained from 1873 participants (945 Uygur ethnic and 928 Kazak ethnic). The genotypes of 14 SNPs were measured for 300 Uygurs and 300 Kazaks. The median 25OHD concentration was as low as 10.4 ng/ml in Uygurs and 16.2 ng/ml in Kazaks. In Uygurs, the prevalence of vitamin D deficiency, in-sufficiency, and sufficiency was 91.2%, 5.8%, and 3.0%, respectively. CYP2R1-rs10766197 was significantly associated with the presence of vitamin D deficiency in the Uygur ethnic population (P=0.019, OR=6.533, 95%C.I.: 361-31.357), while DHCR7/NADSYN1-rs12785878 was significantly associated with the presence of vitamin D deficiency in the Kazak ethnic population (P=0.011, OR=2.442, 95%C.I.: 1.224-4.873). Of 10 SNPs in VDR and GC genes, none was associated with vitamin D status in these 2 ethnic populations.
  
  
  CONCLUSIONS
  Vitamin D insufficiency is highly prevalent in Uygurs and Kazaks living in Xinjiang, China. Polymorphisms in CYP2R1-rs10766197 and DHCR7/NADSYN1-rs12785878 are associated with vitamin D deficiency in Uygur and Kazak ethnic populations.
authors.affiliation: Department of Hypertension, First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, China (mainland).
authors.forename: Xinjuan
authors.initials: X
authors.lastname: Xu
authors.affiliation: Department of Endocrinology, Peking Union Medical College Hospital, Key Laboratory of Endocrinology, Ministry of Health, Beijing, China (mainland).
authors.forename: Jiangfeng
authors.initials: J
authors.lastname: Mao
authors.affiliation: Department of Endocrinology, First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, China (mainland).
authors.forename: Mingchen
authors.initials: M
authors.lastname: Zhang
authors.affiliation: Department of Hypertension, First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, China (mainland).
authors.forename: Haiming
authors.initials: H
authors.lastname: Liu
authors.affiliation: Department of Hypertension, First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, China (mainland).
authors.forename: Haixia
authors.initials: H
authors.lastname: Li
authors.affiliation: Department of Hypertension, First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, China (mainland).
authors.forename: Hong
authors.initials: H
authors.lastname: Lei
authors.affiliation: Department of Cardiology, Xinjiang Armed Police Hospital, Urumqi, Xinjiang, China (mainland).
authors.forename: Lu
authors.initials: L
authors.lastname: Han
authors.affiliation: Department of Hypertension, First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, China (mainland).
authors.forename: Min
authors.initials: M
authors.lastname: Gao
mesh_terms: D000328:Adult; D019733:Carbon-Nitrogen Ligases with Glutamine as Amide-N-Donor / Q000235:genetics*; D002681:China; D053493:Cholestanetriol 26-Monooxygenase / Q000235:genetics*; D000072467:Cytochrome P450 Family 2; D005006:Ethnicity / Q000235:genetics*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D044925:Oxidoreductases Acting on CH-CH Group Donors / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide; D014808:Vitamin D Deficiency / Q000235:genetics*
chemical_list: D000072467:Cytochrome P450 Family 2; C506833:CYP2R1 protein, human; D053493:Cholestanetriol 26-Monooxygenase; D044925:Oxidoreductases Acting on CH-CH Group Donors; C019995:7-dehydrocholesterol reductase; D019733:Carbon-Nitrogen Ligases with Glutamine as Amide-N-Donor; C000593321:NADSYN1 protein, human