Association of Foki and Bsmi RFLP Genotypes in VDR Gene With Hashimoto’s Thyroiditis in Erbil Province

Genetic variations in the Vitamin-D-receptor (VDR) gene have been associated with the pathogenesis of several immune-mediated conditions, notably Hashimoto’s thyroiditis (HT). This work was undertaken to assess whether the widely studied FokI (rs2228570) and BsmI (rs1544410) two well-characterized VDR polymorphisms are associated with susceptibility to HT among females in Erbil Province in the Iraqi Kurdish region. The design of this study was case-control, with 50 female patients diagnosed with HT and 50 healthy female controls, both age-matched (24-59 years). With the guidance of a qualified endocrinologist, various biochemical indicators have been methodically evaluated such as TSH, FT4 and anti-thyroid peroxidase (A-TPO) and Vitamin D3. Genotyping of both polymorphic loci was accomplished via the PCR-restriction fragment length polymorphism (PCR-RFLP) approach. Neither genotype nor allele distributions were differed significantly between groups for either polymorphism (P>0.05). This result was also confirmed by Fisher's exact test, which revealed no significant relationship in genotypic and allelic distribution (P > 0.05). Hardy-Weinberg equilibrium was maintained for the FokI locus in both groups (P > 0.05). For the BsmI polymorphism, however, no similar difference was found, as HWE was only seen in patients, but not in controls (P> 0.05 vs P <0.05). Taken together, the data provide no evidence linking FokI or BsmI variants to Hashimoto’s thyroiditis susceptibility in this female Erbil Province population, and VDR variant frequencies were not different meaningfully between cases and control.