Vitamin D Metabolism Gene CYP27B1 Promoter Polymorphism and Type 1 Diabetes in the Egyptian Population. A genetic Association Study

Background: Epidemiological studies revealed that higher levels of the active metabolite l?-25 dihydroxy vitamin D3 could protect from immune destruction of the pancreatic B cells which leads to type 1 diabetes, l?-25 dihydroxy vitamin D is derived from 25 hydroxy vitamin D by the enzyme 1? hydroxylase encoded by the CYP27B1 gene which located on chromosome 12- 9. 13.1- 13.3. Our aim was to investigate if there is association between the CYP27B1 gene promoter polymorphisms in the Egyptian Population with type 1 diabetes or not. Methods: We studied 90 patients with type 1 diabetes and 90 controls matched for age and sex to evaluate CYP27B1 promoter polymorphism(- 1260) C > A. Results: Analysis of the CYP27B1 promoter (?-1260 C/A) polymorphism revealed that the CC genotype was significantly more frequent in patients with type 1 diabetes mellitus, than in healthy controls (62. 2% vs 33.3 %, P = 0.0001) and the common C allele of CYP27B1 promoter - 1260 A/C polymorphism was significantly more common in type 1 diabetes group compared to control group. Conclusion: The present study may provide evidence that vitamin D metabolism gene CYP27B1 promoter polymorphism increases the risk of developing of type 1 diabetes in Egyptian population. This evidence justifies further studies investigating molecular and cellular actions of vitamin D and mechanisms of its protective effect in type 1 diabetes. Thus vitamin D metabolism gene CYP27B1 promoter polymorphism may be considered as a genetic biomarker for type 1 DM in Egyptian subjects with potential impact on the family counseling and management.