Association of Vitamin D Receptor Gene Polymorphisms and Serum 25-Hydroxy Vitamin D Levels in Vitiligo - A Case-control Study.

BACKGROUND: Vitamin D has stimulatory and protective effects on melanocytes and acts through its nuclear vitamin D receptor (VDR) on target cells. Various single-nucleotide polymorphisms (SNPs) in VDR genes have been described. AIMS: The aim was to study and compare the association of SNP of BsmI/Apa-I/TaqI/FokI/Cdx2 in VDR gene as well as the plasma vitamin D levels in vitiligo patients and healthy controls. METHODS: This was a case-control study, in which 100 patients of vitiligo and an equal number of healthy individuals were studied. The VDR polymorphisms of Bsm I, Apa-I, TaqI, fok I, and cdx2 were investigated, after extraction of genomic DNA by rapid capillary polymerase chain reaction with melting curve analysis, and 25 hydroxy vitamin D levels were measured in cases and controls. RESULTS: The frequency of genotypes (SNP FokI and cdx2) was higher in the patient group versus controls (P = 0.002). The genotype frequency (TaqI and Apa-I) was higher in the patients than the controls for the Tt genotype, but not significantly higher (48% vs. 39%, P = 0.1431). The difference between the groups in frequency of the genotype Aa(TaqI and Apa-I) was statistically significant (P = 0.0001 and P = 0.033). Statistically significant difference was also observed in Apa-I-evaluated alleles in cases when compared to controls (P = 0.0001). There was no significant difference in serum vitamin D levels between various genotypes among cases and controls. Out of 100 cases, 10 were found to have vitamin D levels of >30 ng/ml, 15 had levels between 20 and 30 ng/ml, 52 had ≤20 ng/ml, and 23 ≤ 10 ng/ml, respectively. LIMITATIONS: Since the skin biopsies were not taken from the lesions of vitiligo, the correlation of serum levels with tissue levels of VDR gene was not possible and the role of vitamin D supplementation was not evaluated. CONCLUSION: The single nucleotide gene polymorphisms of various VDR genes as found in the cases might lead to vitamin D deficiency, due to VDR dysfunction, which in turn could increase the susceptibility to develop vitiligo.

Association of Vitamin D Receptor Gene Polymorphism in Adults With Type 2 Diabetes in the Kashmir Valley.

OBJECTIVES: Approx 1 billion people across various ethnic and age groups have vitamin D deficiency. The high prevalence of such a deficiency is an imperative public health issue because hypovitaminosis D is an autonomous risk factor for mortality in the general population. Beyond bone integrity and calcium homeostasis, it is involved in numerous physiologic and pathologic processes. The role of vitamin D in the pathogenesis and prevention of type 2 diabetes mellitus has sparked universal interest. METHODS: This hospital-based case-control study was designed to study the association between 25-hydroxy vitamin D (25[OH]D) levels and the vitamin D receptor (VDR) gene polymorphism with diabetes and to evaluate their roles as risk factors for diabetes. 100 cases and controls were taken. 25(OH)D levels were analyzed by the chemilumenescence method using a Siemens ADVIA Centaur analyzer. Genomic DNA was extracted and Taq-1 and Bsm-1 genotyping in the VDR gene was done by using the polymerase chain reaction followed by restriction fragment length polymorphism (PCR-RFLP). RESULTS: 25(OH)D levels of patients with diabetes were significantly lower than those of controls (19.26±0.95 ng/mL vs. 25.49±1.02 ng/mL; p=0.001). 25(OH)D levels were found to be inversely associated with glycated hemoglobin percentages in cases (r2=0.74). The results suggested that the single nucleotide polymorphisms Taq-1 t(T) allele and b (G allele) in Bsm-1 might be a susceptibility allele for diabetes in the Kashmiri population. CONCLUSIONS: VDR gene polymorphisms appear to be an important genetic determinant in the progression of diabetes. Considering the important predisposition risk factor, we observed that Taq-1 and Bsm-1 were strongly associated with diabetes in northern Indians. But requires further study as a probable genetic risk marker for diabetes.

Promoter Hypermethylation and Its Impact on Expression of MGMT Gene in the GIT Malignant Patients of Kashmiri Origin.

Epigenetic alterations, in addition to multiple gene abnormalities, are involved in the genesis and progression of human cancers. Gastrointestinal tract (GIT) cancer is a major medical and economic burden worldwide. Aberrant methylation of CpG islands within promoter regions is associated with transcriptional inactivation of various tumor suppressor genes. Although a number of cancer-associated genes have been found to be hypermethylated in GIT cancer, valuable methylation markers for early diagnosis and prognostic evaluation of this cancer remain largely unknown. O6-methyguanine DNA methyltransferase (MGMT) is a DNA-repair gene that removes mutagenic and cytotoxic adducts from the O6 position of guanine induced by alkylating agents. MGMT promoter hypermethylation and reduced expression have been found in some primary human carcinomas. We studied DNA methylation of CpG islands of the MGMT gene and its relation with MGMT protein expression in human GIT carcinomas. A total of 210 GIT tumor samples and 90 adjacent normal tissues were analyzed for MGMT promoter methylation by methylation-specific polymerase chain reaction after bisulfite modification of DNA and same samples were analyzed for MGMT protein expression by Western blotting. The methylation frequencies of MGMT gene promoter were 41.4%, 34.2%, and 44.2% in stomach, esophageal, and colorectal cancer cases while as 16.6, 13.3, and 13.3 in respective controls. MGMT protein was found downregulated in controls of all GIT. The results suggest that methylation at CpG islands of MGMT may be responsible for the downregulation of MGMT protein expression in GIT cancers.

Type 2 diabetes and metabolic syndrome - adipokine levels and effect of drugs.

Type 2 diabetes mellitus (T2DM) is a consequence of complex interactions among multiple genetic variants and environmental risk factors. This complex disorder is also characterized by changes in various adipokines. In this study, our objective was to estimate the levels of adiponectin, leptin, and resistin (ALR) in T2DM patients, besides studying the effect of various drugs on their levels. Study participants included 400 diabetic and 300 normal patients from the Department of Endocrinology and Department of Biochemistry, Govt Medical College Srinagar. Subjects were categorized under various groups, i.e., Group 1 (metformin treated) and Group 2 (glimepiride treated), and cases were also categorized as obese with T2DM (Group A), obese without T2DM (Group B), and T2DM only (Group C). The serum ALR levels were estimated by ELISA (Alere), and biochemical parameters were also evaluated before and after treatment. Adiponectin levels were found to be significantly lower in T2DM cases as compared to controls (12 ± 5.5 versus 22.5 ± 7.9 µg/ml), while leptin and resistin levels were found to be significantly higher than controls (14.3 ± 7.4 versus 7.36 ± 3.73 ng/ml) (13.4 ± 1.56 versus 7.236 ± 2.129 pg/ml). Taking the effect of drugs into consideration, the effect on adiponectin and resistin levels was found to be highly significant in Group 2 before and after treatment (11 ± 5 versus 19.2 ± 4.5 µg/ml) (13.6 ± 2.5 versus 7.3 ± 2.9 pg/ml), while more effect was observed in leptin among Group 1 (metformin)-treated cases (27 ± 15 ng/ml versus 15 ± 15 ng/ml). Further the adiponectin levels were found to be significantly lower in Group B, while leptin and resistin levels were found to be significantly higher among obese cases when compared to T2DM cases only. Glimepiride also shows more effect on FBG, HbA1c% levels, while metformin shows more effect on Lipid profile levels. From the study, it can be concluded that ALR levels are affected by use of antidiabetic drugs among which glimepiride shows more effect on adiponectin and resistin levels, while leptin gets affected more by metformin. It can also be proposed that ALR levels are not affected by diabetes only, suggesting that their alterations in T2DM may be due to obesity as we observed more ALR changes in obese cases when compared to T2DM cases, and so there might be an important link between adiposity and insulin resistance.

Diminished expression of MGMT & RASSF1A genes in gastric cancer in ethnic population of Kashmir.

BACKGROUND: Cancer initiation and progression are accompanied by profound changes in DNA. DNA methylation that was the first epigenetic alterations identified in cancer. DNA hypermethylation at promoter sites is closely associated with down regulation of protein and as major participant in the development and progression of series of human tumors. Therefore we hypothesized that promoter hypermethylation of RASSF1A & MGMT gene could influence susceptibility to gastric cancer (GC) as well, and we conducted this study to test the hypothesis in Kashmiri population. METHODS: A hospital based case-control study; including 200 GC cases and 200 matched controls from patients who went surgical resection. Promoter hypermethylation was determined by Methylation Specific Polymerase chain reaction. The expression of MGMT & RASSF1A protein was examined by Western blotting technique. RESULTS: Frequency of promoter region hypermethylation of MGMT gene were 46.5% in cases and 5.5% in controls (P<0.05) while as in case of RASSF1A frequency was 44% in cases and 4.5% in controls (P<0.05). Further, frequency of hypermethylation of both genes was found predominant in males, aged and advanced pathological stage subjects. Loss of MGMT expression was found in 46.5% cases (P<0.05) while as loss of RASSF1A expression was found in 40.5% cases (P<0.05). In both genes a positive correlation was observed between promoter CpG island hypermethylation and down regulation of respective proteins. CONCLUSIONS: These findings indicate that promoter hypermethylation at CpG island may be responsible for reduction of expression at protein level which may be an initial event in carcinogenesis and the progression of GC.