Polymorphisms of the NOS3 gene in Tunisian patients with Behçet's disease.

Behçet's disease (BD) is a multisystem inflammatory disease characterized by recurrent orogenital ulceration, ocular inflammation and skin lesions. Reduced plasma nitric oxide (NO) levels in patients with BD have been implicated in the development of the endothelial abnormalities and thrombotic complications occurring in these patients. Polymorphisms in the endothelial nitric oxide synthase gene (NOS3) have been inconsistently associated with BD. This inconsistency may derive from population stratification secondary to ethnic diversity, and consideration limited to only one rather than combinations of polymorphisms. We studied three genetic variations in the NOS3 gene: a single nucleotide polymorphism in the promoter region -786T>C, in exon 7 (Glu298Asp), and a variable number of tandem repeats in intron 4 (4a4b) of the NOS3 gene in 100 unrelated Tunisian patients with BD and 148 healthy controls. In addition, we also examined the association of NOS3 gene haplotypes with BD. Analyses of the Glu298Asp, -786T>C and 4a4b polymorphisms were made by the polymerase chain reaction (PCR) restriction fragment length polymorphism technique and PCR genotyping, respectively. The distribution of the Glu298Asp genotype differed significantly between patients with BD and controls (P = 0.01). Allele Asp298 was significantly more frequent in patients with BD than in controls (P = 0.005, OR = 1.70, 95% CI 1.14-2.54). In contrast, distribution of alleles and genotypes of -786T>C and 4a4b polymorphisms was not different between the control and BD group. However, the frequency of Asp-T-4b haplotype was significantly higher in patients with BD than in healthy controls. By gender, the signification remained only for heterozygous men (P = 0.03) and homozygous women (P = 0.02). These results suggest that Glu298Asp polymorphism of the NOS3 gene is associated with BD susceptibility in Tunisian patients.

The G3057A LEPR polymorphism is associated with obesity in Tunisian women.

OBJECTIVES: The aim of this study was to evaluate the effect of the G3057A (rs62589000) LEPR polymorphism on obesity risk and plasma leptin, insulin, and lipid levels in a sample of the Tunisian population. DESIGN AND METHODS: Three hundred and ninety-three obese patients and 317 controls participated in this study. The G3057A genotype was determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. RESULTS: In the entire study sample, no significant differences in genotype frequencies were observed between obese patients and controls. However, stratified analysis by gender revealed a quantitative increase in the variant allele (33.3% vs. 25.8%; χ(2)=4.90, p=0.026) in obese women (but not men) compared to controls. When a dominant model of inheritance was assumed, the GA+AA genotypes were more prevalent in these obese female patients than in controls (58.3% vs. 47.8%; χ(2)=4.08, p=0.044). Unconditional logistic regression showed that in women only, obesity risk was significantly higher for homozygotes for the variant allele (OR=2.73, 95% CI 1.03-7.21) and for carriers of GA+AA genotypes (OR=1.53, 95% CI 1.01-2.31) compared with homozygotes for the normal allele. The association between the G3057A LEPR variant and obesity remained statistically significant even after adjustment for age. No relationship was found between the G3057A LEPR polymorphism and leptin and insulin levels. Additionally, this LEPR gene variant had no effect on plasma lipid concentrations. CONCLUSION: There is evidence in this study that the G3057A LEPR polymorphism is associated with obesity in Tunisian women.

Lack of association between monocyte protein-1 (MCP-1) -2518 A>G chemoattractant and C-C chemokine receptor 2 (CCR2) Val64Ile polymorphisms and multiple sclerosis in a Tunisian population.

Chemokines and their receptors are known to mediate inflammation and tissue damage in autoimmune disorders such as multiple sclerosis (MS). Multiple sclerosis is an inflammatory disease of the central nervous system, characterized by myelin damage and neurological complications. Monocyte chemoattractant protein-1 (MCP-1) interacts with the C-C chemokine receptor 2 (CCR2) and plays a role in the migration of leukocytes into the central nervous system, thus contributing to the T cell-mediated pathogenesis of MS. Genomic DNA obtained from 58 MS patients and 72 healthy controls was tested for the MCP-1 -2518 A>G and CCR2 Val64Ile polymorphisms using polymerase chain reaction-restriction fragment length polymorphism analysis. Neither the MCP-1 -2518G (p=0.43) nor the CCR2 64Ile (p=0.52) variant contributed to the risk of MS in Tunisians.

The -2548G/A LEP polymorphism is associated with blood pressure in Tunisian obese patients.

OBJECTIVE: To examine the association of a common -2548G/A (rs7799039) promoter variant of the human leptin gene (LEP) with obesity or body mass index (BMI) and its associated phenotypes such as blood pressure variability and the prevalence of hypertension in a sample of the Tunisian population. DESIGN AND METHODS: Two hundred and twenty-nine obese patients were screened and compared with 251 normal weight subjects. The -2548G/A LEP polymorphism was analysed by PCR-RFLP procedure. RESULTS: No significant association was found between the -2548G/A polymorphism and obesity or BMI. However, in obese patients subjects with AA genotype had significantly higher systolic (p = 0.003) and diastolic (p = 0.002) blood pressure compared with those with GA or GG genotypes. Stratified analysis by gender revealed that male patients but not female homozygous for -2548A allele exhibited significantly increased systolic (p = 0.01) and diastolic (p<0.001) blood pressure than did carriers of -2548G allele. Multiple linear regression analysis revealed that AA genotype significantly affect systolic and diastolic blood pressure in obese men. Additionally, significant association between AA genotype and higher prevalence of hypertension was found in male patients (p = 0.03). CONCLUSION: The present study showed that the -2548G/A LEP polymorphism is associated with blood pressure in obese male patients.