Vitamin D receptor gene polymorphisms influence susceptibility to type 1 diabetes mellitus in the Taiwanese population

OBJECTIVE Vitamin D and its receptor have been suggested to play a role in the pathogenesis of type 1 diabetes mellitus, We have therefore studied the influence of vitamin D receptor (VDR) gene polymorphisms on susceptibility to type 1 diabetes, and rates of glutamic acid decarboxylase (GAD(65)) aut oantibody and islet cell autoantibody (ICA(512)) positivity. SUBJECTS AND MEASUREMENTS One hundred and fifty-seven type 1 diabetic patie nts and 248 unrelated normal controls were recruited for this study. Genomi c DNA was extracted from peripheral blood leucocytes, All type 1 diabetic p atients and controls were genotyped using polymerase chain reaction (PCR) a nd restriction fragment length polymorphism (RFLP), for three restriction s ites in the VDR gene, Bsml, Apal and Taql, The chi(2) test was used to comp are the frequency of the VDR gene polymorphisms in patients and normal cont rols. The association of VDR gene polymorphisms in type 1 diabetes with the presence of GAD(65) and ICA(512) autoantibodies were also examined using t he chi(2) test. RESULTS The allele frequency of the Bsml and Apal polymorphisms, but not Ta ql polymorphism, differed between patients and controls (Bsml P=0.015; Apal P=0.018; Taql P=0.266). However, after correction for the three different polymorphisms tested, only the Bsml was significant (pc = 0.045). CONCLUSIONS Vitamin D receptor gene polymorphisms were associated with type 1 diabetes in a Taiwanese population. However, functional studies are need ed to establish the role of the vitamin D receptor in the pathogenesis of t ype 1 diabetes mellitus.