Association of vitamin D receptor gene BsmI polymorphisms in Chinese patients with systemic lupus erythematosus.

The purpose of this study was to evaluate whether vitamin D receptor (VDR) genes BsmI polymorphisms were markers for susceptibility to or severity of systemic lupus erythematosus (SLE) in Chinese patients in Taiwan. The study included 47 Chinese patients with SLE. In addition, 90 unrelated, healthy individuals living in central Taiwan served as control subjects. Each polymorphism was detected as a result of polymerase chain reaction (PCR)-based restriction analysis. A PCR product length was determined to be 580bp (BB) whereas two fragments of 405 and 175bp were determined to be excisable lengths (bb) by BsmI endonuclease. The relationship between Bsm polymorphisms and clinical manifestations of SLE was evaluated. We found that BB was significantly more common and bb less common in SLE than in control group (chi2 = 54.2, P < 0.0001). In addition, the frequency of B allele was also significantly more common in patients with SLE than in the healthy control subjects (chi2 = 38.7, P < 0.0001), giving an odds ratio of 7.14 (95% confidence interval 3.53-14.4). In the SLE patients, we did not detect any associations of VDR genotype with the clinical, laboratory profiles, or lupus nephritis (chi2 = 2.34, P = 0.3). This study indicated an increased distribution of VDR BB genotype and B allelic frequencies in the Chinese SLE patients in Taiwan. However, there were no associations between the frequency of VDR allelic variations and clinical manifestations, laboratory profiles, or lupus nephritis.