DNA Repair Enzyme XRCC4 30 bp Indel Intron 3 Locus Significant Association with Predisposition of Cataract in Senility.

Impaired DNA damage repair cascade can disrupt the lens transparency due to aging-associated oxidative stress. The aim of study was to assess the association of 30 bp indel mutation (rs28360071) in XRCC4 gene with susceptibility of cataract in senility. The study followed case-control design with a total of n = 200 participants and divided equally into senile cataract patients and control groups. Conventional polymerase chain reaction (PCR) was performed for the genotyping of XRCC4 (rs28360071) mutation. In statistical measures, SPSS ® 20.0 software, MedCal©, and SNPStats© tools were used for data analysis. Distribution of homozygous D/D and mutant D allele was higher in senile cataract patients in comparison to controls. XRCC4 (rs28360071) mutation was significantly associated with predisposition senile cataract (χ2 = 13.96, adjusted OR = 2.29, 95% CI: 1.5-3.4, p < 0.001). Codominant model was suggested to be a best fit model. Mutant D/D genotype described significant association with LDL (adjusted OR = 1.67, 95% CI: 0.14-1.45, p = 0.03),and HDL (adjusted OR = 1.66, 95% CI: 0.92-2.31, p = 0.05) cholesterol with higher risk of senile cataract. XRCC4 (rs28360071) mutation may serve as a potential biomarker for the prognosis of cataract in senility. It can used to measure interruption in NHEJ repair pathway to indicate DNA damage in lens epithelial cells which could accelerate cataractogenesis with aging.

Clinical Association of Biochemical Variations Among Multilocus Genotypes of Antioxidant Enzymes with Susceptibility of Cataract in Hyperglycemia.

Hyperglycemia plays a pronounced role in accelerating the process of aging due to high oxidative stress which triggers dyslipidemia and subsequently led to the progression of cataract. The aim of this study was to investigate lipid profile and its relationship with genotypes of SOD1, GPX1, and CAT variants in cataract patients. Total n = 680 samples were screened in four groups: senile cataract (SC), diabetic cataract (DC), type 2 diabetes mellitus (DM), and controls (CL). Lipid profile was estimated and compared between groups, and its correlation was tested with glycemic markers. Association of SOD1 50 bp Indel, GPX1 (rs1800668), and CAT (rs1001179) genotypes with all clinical variables was investigated in cataract groups by regression statistics in SPSS® 16.0. Comparative analysis revealed that amount of total cholesterol and low-density lipoprotein parameters were significantly higher in both groups of cataracts when compared with controls (p < 0.01). Statistically higher levels of triglycerides were also evident in DM patients as compared with other three groups (p < 0.01). Significant weak positive correlation of glycated hemoglobin, fasting (FBG), and random blood glucose (RBG) levels was observed with triglycerides in DM (r = 0.16), SC (r = 0.15), and DC (r = 0.18) groups. Mutant genotype of SOD1 and CAT variants indicated significant association with TC, whereas GPX1 variant with FBG levels in accelerating predisposition of cataract in patients with diabetes (OR > 1.0). Outcomes suggested that TG may serve as a potential biomarker of lipid profile with manifestation of cataract in type 2 DM. Furthermore, hypercholesterolemia and hypertriglyceridemia demonstrated an inducing role in the pathogenesis of cataract with aging in hyperglycemia.

Predisposition of SOD1, GPX1, CAT genetic variants and their haplotypes in cataractogenesis of type 2 diabetes mellitus in Pakistan.

AIMS: Cataract formation is accelerated by hyperglycemia due to the excessive production of oxidative stress. This study aimed to examine the underlaying role of glutathione peroxidase 1 (GPX1) rs1800668, catalase (CAT) rs1001179 and superoxide dismutase 1 (SOD1) 50 bp Indel promotor region variants in the pathogenesis of cataract in patients with diabetes. METHODS: A population-based case-control study of n=680 individuals was conducted which comprised of four respective groups: type 2 diabetes mellitus, diabetic cataract, senile cataract patients and controls. Screening of genotypes was performed by allele-specific (AS) and conventional polymerase chain reaction (PCR). Statistical testing was carried out using SPSS© 20.0, MedCal© and SNPStats© software's. Bioinformatics analysis of linkage disequilibrium was done by HaploView© software 7.0. RESULTS: GPX1 (rs1800668) showed significant association with higher susceptibility of opacification in type 2 diabetes mellitus (χ2=23.0, Adjusted OR=1.63, 95% CI: 1.05-2.49, p<0.001). A protective role was anticipated by CAT variant (rs1001179) for the development of resistance against the pathogenicity of cataract with diabetes (χ2 = 107, Adjusted OR=0.17, 95% CI: 0.10-0.29, p<0.001). Linkage disequilibrium (LD) plot of GPX1 and CAT variants revealed that CTC-CTT haplotypes demonstrated the presence of linkage (D'=1.0) and co-inheritance (LOD=13.84) in patients of diabetic cataract. CONCLUSIONS: GPX1 (rs1800668) variant may serve as an antioxidant biomarker for the assessment of risk for cataract in type 2 diabetes mellitus. GPX1 enzyme owed an antioxidant activity which can reduce the oxidative stress and hence could develop resistance in cataractogenesis. The findings could be beneficial as a potential target to the future pharmacogenomic studies of cataract prevention and eradication in diabetes mellitus.

Vitamin D receptor gene polymorphism TaqI (rs731236) and its association with the susceptibility to coronary artery disease among Pakistani population.

BACKGROUND: Coronary artery disease (CAD) is a leading cause of mortality in Pakistan and also worldwide. Vitamin D receptor (VDR) regulates the transcription of many genes and has a significant impact on inflammation and the morphology of cardiac cells. Genetic variation in the VDR gene such as the TaqI polymorphism (rs731236) may have an impact that causes adverse effects. Accordingly, it is important to determine possible association of the TaqI polymorphism (rs731236) with CAD. METHODS: The study included blood samples from 1016 subjects: 516 from CAD patients and 500 from age- and gender-matched controls. Genomic DNA was extracted by standard salting out method. Targeted variation was amplified by an allele-specific polymerase chain reaction (PCR). PCR products were examined and genotyped on agarose gel electrophoresis represented by an amplified product size of 148 bp followed by Sanger sequencing to validate variations. RESULTS: Serum vitamin levels, as observed using enzyme-linked immunosorbent assay, were found to be insufficient in both CAD patients (20.52 ± 0.06 ng/ml) and controls (21.6981 ± 0.05 ng/ml). The TaqI polymorphism (rs731236) T>C was found to be significantly associated with CAD (p < 0.0001). The odds ratio showed that the risk increases by 1.8-fold with variant C allele. Dominant, co-dominant and over dominant genetic model analyses suggested that the TC genotype might be a risk factor involved in the possible association with susceptibility to CAD. CONCLUSIONS: The TaqI polymorphism (rs731236) in the coding region may affect the function of the receptor by altering the binding site, which might participate in an inflammatory response and increase the risk for developing susceptibility to CAD.

A Study on Catalase Gene Promoter Polymorphism -21 A/T (rs7943316) in Healthy Pakistani population.

BACKGROUND & OBJECTIVE: Catalase (CAT) is an important endogenous antioxidant enzyme that detoxifies H2O2 into water and oxygen, consequently limiting the deleterious effects of reactive oxygen species. It has suggested that CAT-21A/T (rs7943316) OMIM: 115500 gene promoter polymorphism is predominantly associated with different human disorders such as hypertension, cancers, diabetes, nephropathy, and other diseases accompanied by oxidative stress. This study was designed to investigate the prevalence of mutant T allele frequency in healthy individuals. METHODS: The study group consisted of 110 healthy individuals were enrolled from Baqai Institute of Diabetology and Endocrinology (BIDE), Karachi, Pakistan, during the period of April 2010 to May 2013. DNA was isolated from leukocytes. Genotyping of CAT-21A/T (rs7943316) gene promoter polymorphism was carried out using thermal cycler followed by RFLP. Blast N analysis was performed for the confirmation of gene sequences. RESULTS: In CAT-21A/T (rs7943316) gene promoter polymorphism, wild type genotype (AA) was observed in 18.26% and alterered genotype (AT/TT) found in 81.74% cases. CONCLUSIONS: Data demonstrates that frequency and distribution of mutant T allele was more prevalent as compared to wild type A allele in the study group.

Common variant within the FTO gene, rs9939609, obesity and type 2 diabetes in population of Karachi, Pakistan.

AIM: To determine the effect of genetic variants within the FTO gene (rs9939609) on obesity related traits and type 2 diabetes in South Asian population of Karachi, Pakistan. METHODS: A case-control study was conducted at Baqai Institute of Diabetology and Endocrinology (BIDE), Baqai Medical University situated in Karachi. A total of 296 patients with known type 2 diabetes and 198 controls aged greater than and equal to 45 years were recruited. The Anthropometric, clinical and biochemical data was collected on a structured questionnaire. Single nucleotide polymorphism (SNP) in FTO gene was identified by Amplification Refractory Mutation System-Polymerase Chain Reaction (ARMS-PCR). Association between the single nucleotide polymorphism and categorical variables such as type 2 diabetes and obesity category was tested through logistic regression analysis. RESULTS: We observed a strong association of the minor allele A at rs9939609 with type 2 diabetes. Significant difference was observed in frequency of FTO genotype when diabetic subjects were compared with controls in co dominant, dominant and recessive models. This association remained significant even after adjusting for body mass index (BMI) and for waist circumference. The frequency of homozygous risk Alleles (AA) was found to be higher in obese & overweight (≥ 23 kg/m(2)) and females with central obesity in our study population. The association of FTO variant with BMI and central obesity does not reach to statistical significance. CONCLUSION: In the study population of South Asian ancestry, variants of the FTO gene predispose to type 2 diabetes, but not entirely through their effect on BMI.

Glycemic control, dyslipidemia and endothelial dysfunction in coexisted diabetes, hypertension and nephropathy.

Diabetes mellitus is a chronic metabolic disorder that can lead to serious cardiovascular, renal, neurologic and retinal complications. Diabetes clustered with hypertension and nephropathy has become the leading cause of end-stage renal disease globally. This study describes diabetes, hypertension and nephropathy with reference to glycemic control, dyslipidemia and endothelial dysfunction indicating the foremost basis of morbidity and mortality world wide and rapidly progressing in Pakistan. Study subjects selected and divided in four groups (60 each) followed by institutional ethical approval and informed consent. Group 1: non-diabetic, normotensive control subjects; Group 2: diabetic, normotensive patients; Group 3: diabetic, hypertensive patients and Group 4: diabetic, hypertensive patients with nephropathy. Their fasting blood samples analyzed for the estimations of blood glucose, HbA1c, serum triglyceride, cholesterol, LDL-cholesterol, HDL-cholesterol, urea, creatinine, nitric oxide and sialic acid levels. Results showed that all the groups showed significant rise in fasting blood glucose. Similarly HbA1c levels were also significantly high in all the patients as compared to controls. Group 2 showed significantly high serum cholesterol and LDL levels and low HDL levels. Group 3 and 4 showed significantly high serum triglyceride, cholesterol and LDL levels where as low HDL levels as compared to controls. Group 3 showed significantly high serum creatinine. Group 4 showed a significantly high serum urea and creatinine as compared to controls. Persistent albuminuria was characteristic in Group 4 patients. Significantly low production of serum nitric oxide with high concentration of serum sialic acid was observed in Group 3 and 4 as compared to controls. Results indicate a clear relationship of declining renal function with poor glycemic control, abnormal lipid metabolism, endothelial dysfunction and initiation of acute phase response in tissues affected from the microvascular complications of diabetes like hypertension and nephropathy. It must be taken into account while screening diabetic patients to get them rid of progressive renal impairment leading to end stage renal disease.