Investigation of vitamin D receptor polimorphisms in maturity onset diabetes of the young

Diabetes is a metabolic disease characterized by hyperglycemia resulting from defects in insulin action, secretion, or both. Diabetes primarily encompasses two types: type 1 diabetes (T1DM) and type 2 diabetes (T2DM). Other less commonly known types characterized by a single gene mutation causing dysfunction in beta cells include Neonatal Diabetes, Maturity-Onset Diabetes of the Young (MODY), and Mitochondrial Diabetes. MODY, first described by Tattersall in 1974, represents a dominant and hereditary form of insulin-independent diabetes diagnosed before the age of 25. The identification of MODY significantly contributes to the diagnosis and treatment of diabetes. Vitamin D is considered a hormone that exhibits its effects through the vitamin D receptor in pancreatic beta cells. Both VDR and 1-α-OH'ase are present in pancreatic beta cells, and vitamin D is important for insulin synthesis and secretion. Vitamin D deficiency and diabetes are commonly observed in the population. Epidemiological studies have observed that low levels of vitamin D increase the risk of diseases such as T2DM, cardiovascular diseases, autoimmune diseases like T1DM, and multiple sclerosis. In our study, we aimed to investigate the impact of VDR gene TaqI rs731236 and VDBP gene Eco130I (StyI) rs4588 polymorphisms on the progression of the disease and the biochemical parameters based on the levels of vitamin D in MODY patients. We believe that examining the levels of D vitamin, VDR and VDBP gene polymorphism distributions in the Turkish population, which has recently seen an increasing prevalence of MODY, will contribute to the diagnosis and progression of the disease. Our study is divided into two groups as patients and controls. In the patient group triglyceride (p<0.05) and free T4 (p<0.05), CRP (p<0.05), hemoglobin (p<0.05), hematocrit (p<0.05) levels and family history of diabetes (p<0.05), neuropathy (p<0.05), retinopathy (p<0.05) values were found higher and statistically significant compared to the control groups. In our study, the heterozygous mutant 'CT' variant of the VDR gene rs731236 polymorphism and the homozygous 'CC' variant of the VDBP gene rs4588 polymorphism were found higher compared to the other genotypes. It was observed that the VDR rs731236 T>C (TaqI) mutant CC genotype and the VDBP rs4588 C>A (StyI) normal CC genotype were effective on parameters related to kidney and liver functions. This study will be carried out between 2022-2024. It was prepared with the contribution of Haliç University, Faculty of Arts and Sciences, Department of Molecular Biology and Genetics to scientific research and applications.