Vitamin D Receptor Gene 3' End Polymorphisms in Patients with Graves' Disease in Koreans / 대한내분비학회지

ABSTRACT

BACKGROUND: The aim of this study was to evaluate the association of vitamin D receptor (VDR) gene polymorphisms with Graves' disease in Koreans. We also investigated the association of VDR gene polymorphisms with the clinical characteristics and titers of TSH receptor antibodies in patients with Graves' disease. SUBJECTS AND METHODS: The VDR gene polymorphisms were evaluated in 117 patients with Graves' disease and 156 normal controls. The polymorphisms were represented according to restriction fragment length polymorphism; Aa(ApaI), Bb(BsmI) and Tt(TaqI), with the capital letters signifying the absence, and small letters the presence of restriction sites. RESULTS: The distribution of the ApaI polymorphism genotype was AA(17.1%), Aa(50.4%) and aa(32.5%). The BsmI polymorphism genotype distribution was BB(7.1%), Bb(35.4%) and bb(57.5%); and the TaqI polymorphism genotype distribution was TT(92.6%), Tt(6.2) and tt(1.2%). No significant differences in either genotypic or allelic distributions were observed, between the patients with Graves' disease and the normal controls, associated with the VDR gene polymorphisms. No significant differences were observed with age, sex, size of goiter or the presence of ophthalmopathy, in patients with Graves' disease associated with the VDR gene polymorphisms. However, the titers of the TBII were significantly higher in the aa than the Aa genotype, and were also higher in the group without the A allele than in groups with(aa 55.9+/-18.3 vs. Aa 43.2+/-23.4, p<0.05; aa 55.9+/-18.3 vs. AA and Aa 42.9+/-23.5, p<0.05). Thyroid stimulating antibodies measured with a CHO cell transfected with a wild type of human TSH receptor, were also higher in patients without the A allele than in those with(aa 620+/-829 vs. AA and Aa 353+/-306, p<0.05). The titers of the anti-thyroglobulin antibodies were significantly higher in the groups not containing the B allele than in the group that did(bb 50.9+/-42.8 vs. BB and Bb 31.9+/-38.9, p<0.05). The serum alkaline phosphatase activities were higher in the group having the b allele than in the group that did not(Bb and bb 139+/-68 vs. BB 82.2+/-15.5, p<0.05). CONCLUSIONS: The VDR gene 3' end polymorphism was not associated with susceptibility to Graves' disease in Koreans. The studies of other polymorphism sites of the VDR gene might be required to elucidate the association of VDR gene polymorphisms with Graves' disease in Koreans.