VITAMIN D RECEPTORS GENES POLYMORPHISMS AND OXIDATIVE DNA DAMAGE AMONG KURD PATIENTS WITHTYPE 2 DIABETES, KURDISTAN REGION (IRAQ)
Background: Although the relationship between vitamin D deficiency and oxidative DNA damage has been previously reported, few studies have examined vitamin D receptor (VDR) gene polymorphisms for association with the risk of DNA damage. This study aimed to identify vitamin D receptor genotypes in patients with type 2 diabetes and healthy subjects, as well as identify the relationship with oxidative DNA damage.
Methods: The study enrolled 162 subjects, 96 with type 2 diabetes and 66 healthy individuals were randomly selected to participate in prospective genotype detection by standard polymerase chain reaction methods and restriction fragment length polymorphism (PCR-RFLP). The polymorphism of FokI and BsmI genes and its association with DNA damage were determined. The main outcome measures were oxidative DNA damage marker including serum 8-hydroxy 2-deoxy guanosine (8-OHdG) and 25 hydroxy vitamin D [25(OH) D].
Results: Notable statistical significance exists in the frequency of genotype and allele of FokI (VDR 2228570 C>T) in patient group (OR 9.7, P=0.01) compared with the healthy individual group. No significant difference was found in the patient group (OR 0.74, p=0.66) in the frequency of genotype and allele of BsmI (VDR 1544410 A>G.). The frequency allele carrier of the (VDR 2228570) C allele was higher in the patients sub- group with high DNA damage than in the healthy individuals (OR=1.22, CI=0.02-18.9, p= 0.70). The frequency allele carrier of the (VDR 1544410) G allele was also higher in the patients sub-group with a high level of DNA damage than in the healthy individuals (OR=1.38, CI=0.13-16.8, p=0.57).
Conclusion: Our results suggest a significant relationship between DNA damage and the gene polymorphism FokI (VDR 228570 C>T) CC and its allele C among diabetic patients. Additionally, our results suggest that the high prevalence of FokI (VDR 228570 C>T) polymorphism among patients group may be a genetic marker of susceptibility for diabetes in our population