Association of Vitamin D Receptor (VDR) FokI Polymorphism with Type 1 Diabetes Mellitus in a Sulaimani City

Volume 28 , Issue 1 , June 2026 , Pages 29-42

Authors

Zanyar A. Hussein 1 ; Gaza F. Salih 1

1 University of Sulaimani, College of Science, Biology Department

DOI logo 10.17656/sujpas.1132

Keywords

Abstract

Type 1 diabetes mellitus is an autoimmune disorder characterized by pancreatic β-cell destruction and lifelong metabolic complications. Vitamin D and its receptor (VDR) play an important role in immune regulation and insulin secretion. This study aimed to investigate the association between the VDR Fok1 polymorphism (rs2228570), Vitamin D status, and T1DM in a pediatric Kurdish population from Sulaimani city, Iraq. A case-control study was conducted, including 71 participants: 40 children and adolescents with T1DM and 31 age- and sex matched healthy controls (2-18 years). Genomic DNA was extracted, and VDR Fok1 genotyping was performed using PCR and sequencing. Clinical parameter including serum vitamin D3 levels, random blood sugar, Hemoglobin A1c, and body mass index (BMI), were assessed. Allele frequency analysis revealed a significantly higher frequency of the C allele in T1DM patients than in controls (76.3% vs. 58.1%; P < 0.05), whereas the T allele was more prevalent in controls. The CT heterozygous genotype was significantly more frequent among controls than T1DM patients (64.5% vs. 32.5%, P=0.043). Serum vitamin D3 levels were significantly lower in T1DM patients (P<0.001), whereas HbA1c and BMI values were significantly higher compared with controls (p<0.001). In conclusion, the VDR Fok1 polymorphism, particularly the CC genotype, is associated with T1DM in the pediatric Kurdish population. These findings support a potential role of VDR genetic variation and Vitamin D status in T1DM susceptibility, warranting further studies with larger sample sizes.

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  • First online25 June 2026
  • Published at25 June 2026

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