Type 2 diabetes mellitus (T2DM) is a chronic degenerative disease, phenotypically and genetically heterogeneous, characterized by high levels of glucose and metabolic complications. Insulin receptor substrate 1 (IRS-1) plays a key role in the insulin-stimulated signal transduction pathway. A glycine-to-arginine substitution at codon 972 (G972R) (rs1801278) in the IRS-1 gene has been associated with impaired insulin action. Another SNP rs2943641 in the IRS-1 gene has been found to be associated with T2DM and insulin resistance in genome-wide association studies. The aim of the present study was to evaluate whether rs1801278 and rs2943641 are associated with increased risk of T2DM in the Saudi population. The study included 376 T2DM cases and 380 healthy controls. Genomic DNA was isolated using a commercially available kit supplied by Norgen Biotech Corp. Genotyping was performed by PCR and RFLP analysis. There was a significant difference in the genotypic distribution as well as allelic frequency between the T2DM cases and controls in case of both the polymorphisms for rs1801278 (1.752, 95 % CI 1.002-3.121; p = 0.04), and for rs2943641 (OR = 1.482, 95 % CI 1.176-1.867; p = 0.001). In conclusion, both the (rs1801278 and rs2943641) polymorphisms are associated with T2DM in the Saudi population.

Our results confirm that APOE variants are associated with obesity in the Saudi population.

BackgroundType 2 diabetes mellitus (T2DM) is a chronic and multifactorial disease with a rapidly rising incidence in Saudi Arabia. Various genes including zinc finger protein 1 (JAZF1) and tetraspanin 8/leucine-rich repeat-containing G protein-coupled receptor (TSPAN8/LGR5) have been previously described to be associated with T2DM. This study investigated the association of JAZF1 (rs864745) and TSPAN8 (rs7961581) with T2DM in a Saudi population.MethodsGenomic DNA samples from 400 Saudi T2DM patients and 400 healthy controls were genotyped and analyzed using a polymerase chain reaction-restriction fragment length polymorphism method. The difference between the genotype frequencies were carried out with Chi-square test. Odds ratio, 95 % confidence intervals and p values were calculated using multinomial logistic regression. Dominant and recessive models were implemented to show the statistical significances. Analysis of variance was used to compare differences between genotypes for the various parameters.ResultsDistribution frequencies of the AA, AG, and GG genotypes of JAZF1 (rs864745) differed significantly among T2DM patients and healthy controls (p < 0.05). The AG and GG genotypes were independently and significantly associated with a T2DM risk after adjusting for factors such as age, sex, and body mass index [odds ratio (OR) 2.1 (95 % confidence interval (CI) 1.3–3.4); p = 0.002] and [OR 1.9 (95 % CI 1.2–3.1); p = 0.005], respectively. A genotype-based stratification of anthropometric and biochemical data revealed that the AG + GG genotype is associated with waist circumference (p = 0.04) and fasting blood glucose (p = 0.01) and high-density lipoprotein cholesterol levels (p = 0.02). None of the allele or genotype showed the significant association between the T2DM cases and control subjects in rs7961581 polymorphism in TSPAN8/LGR5 gene.ConclusionThe rs864745 variant in JAZF1 gene may act as genetic risk factors for the development of T2DM in a Saudi population.

BACKGROUNDFamilial hypercholesterolemia (FH) is an autosomal dominant condition characterized by abnormal levels of low-density lipoprotein (LDL) in the blood. FH is a risk factor for atherosclerosis and cardiovascular disease. The relationship between the paraoxonase 1 (PON1) gene, atherosclerosis and coronary artery disease has not been studied in Saudi patients.OBJECTIVETo investigate the genetic associations of the Q192R polymorphism in the PON1 gene with FH in Saudi patients.DESIGNCase-control study.SETTINGTertiary care center, Riyadh.METHODSTwo hundred Saudi patients were enrolled in this study, including 100 patients with FH and 100 healthy controls, during the period from January 2012 to March 2013. Serum was separated from coagulated blood (3 mL) and used for analysis of lipid profiles. Genomic DNA was isolated from anticoagulant-treated blood (2 mL). Genotyping for the Q192R polymorphism was performed by polymerase chain reaction-restriction fragment length polymorphism analysis, followed by 3% agarose gel electrophoresis.MAIN OUTCOME MEASUREThe strength of association between the Q192R polymorphism and FH in the Saudi population.RESULTSWe confirmed that QR versus QQ (odds ratio [OR]: 1.55; 95% confidence interval [CI]: 1.05–3.43; P=.03), QR+RR versus QQ (OR: 1.98; 95% CI: 1.13–3.49; P=.01), and R versus Q (OR: 1.68; 95% CI: 1.09–2.59; P=.01) in the Q192R polymorphism were associated with FH in the Saudi population.CONCLUSIONIn conclusion, the Q192R polymorphism in the PON1 gene is associated with FH in the Saudi population. Our results confirmed that the R allele, QR, and dominant model genotypes were associated with FH.LIMITATIONOnly a single variant (Q192R) was analyzed, and the medical and family histories of the patients were not known.

BackgroundFatty acid-binding protein 2 (FABP2) is an intracellular protein expressed exclusively in the enterocytes of proximal small intestine. FABP2 has a high affinity for saturated and unsaturated long-chain fatty acids and is believed to be involved in the absorption and transport of dietary fatty acids.MethodsThis is a case–control study conceded in 438 T2DM cases and 460 subjects with normal glucose levels and non-obese considered as healthy controls. Allelic discrimination was performed using TaqMan single-nucleotide polymorphism was carried out by real time-polymerase chain reaction (RT-PCR) assays using purified DNA.ResultsClinical data and anthropometric measurements except age, glucose levels and lipid profile of the patients were significantly different from those of the controls (p < 0.05). Statistical analyses failed to show any type of significant association of the polymorphism between cases and controls. However logistic regression analyses was suggests that the TT genotype is significantly associated with male patients (p = 0.001). None of the allele or genotypes of FABP2 A54T was associated with T2DM cases versus the controls (AT genotype, OR = 0.85 (0.64-1.12), p = 0.25; TT genotype, OR = 0.66 (0.39-1.11), p = 0.11; T allele, 0.82 (0.67-1.02), p = 0.08).ConclusionIn conclusion, this study suggests that the above named variant in FABP2 gene is not potential contributor to the risk of T2DM and related traits in a Saudi population. However TT genotype is a risk factor for the disease in males.