engleski

Vitamin D receptor allele combinations and Fok I polymorphism influence genetic susceptibility to type 1 diabetes in Dalmation population

Vitamin D and its receptor gene (VDR) have immunomodulatory properties and influence insulin secretion. Recent data indicate VDR polymorphisms to be associated with type 1 diabetes mellitus (T1DM) and therefore were studied FokI polymorphism in exon 2. 134 individuals with T1DM and 132 control subjects from the Dalmatia population of South Croatia were examined. Fok I genotyping was performed by PCR amplification followed by FokI endonuclease restriction. Data were analysed using the chi-square test. On the basis of our previous research, haplotype analysis of VDR polymorphisms BsmI, ApaI and TaqI and their association with susceptibility to T1DM have been investigated. Estimates of haplotypes were made using statistical program EH+. FokI polymorphism showed unequal distribution (p=0.049) between T1DM cases and controls indicating ff genotype to be associated with development of T1DM and Ff genotype to be a protective one. BsmI, ApaI and TaqI polymorphisms were found to be in strong linkage disequilibrium (LD) (p=0.0001). Bat haplotype was observed 11 times in control and not once in T1DM individuals (p=0.0007) and therefore revealed it's possible protective role. No significant LD between FokI and any other polymorphisms was detected but, nevertheless, bf haplotype was significantly more frequent in T1DM patients (p=0.0168) while the aF haplotype was observed more times in controls (p=0.0413). Our findings indicate that VDR FokI polymorphism and several VDR allele variants are associated with susceptibility to T1DM in the Dalmatian population.

Vitamin D receptor; Interleukin 1 receptor; genotype; haplotype; linkage disequilibrium; Type 1 diabetes; Dalmatia

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