Interleukin 10 (IL-10) gene variants and haplotypes in Tunisian women with polycystic ovary syndrome (PCOS): a case-control study.

BACKGROUND: Polycystic ovary syndrome (PCOS) is a prevalent endocrine disorder that affects women in their child-bearing age, and is associated with insulin resistance and type 2 diabetes. The etiology of PCOS involves multiple factors including genetic, metabolic and immunological factors. Interleukin - 10 (IL-10), as an anti-inflammatory cytokine, plays a critical role in this regard. We investigated the potential role of IL-10 gene variants in the development of PCOS in Tunisian population. METHODS AND RESULTS: 115 cases and 120 controls were recruited in the current case control study. Rotterdam consensus criteria were used to diagnose PCOS patients. Genotyping for IL-10, rs1800896, rs1800871 and rs1800872 variants, was performed by real time PCR. The results obtained showed that the minor allele frequency of rs1800896, rs1800871and rs1800872 were comparable between PCOS cases and control subjects (P = 0.30, P = 0.71, and P = 0.57 respectively). The distribution analysis revealed an unsignificant association of the three tested variants, in all genetic models. Haplotype analysis identified one haplotype CCA with a protective role in PCOS development (P = 0.05; OR (95% CI) = 0.56 (0.32 - 0.99)). This association did not persist after adjustment for multiples covariates (Pc = 0.154). CONCLUSIONS: Our study is the first to show how ethnicity influences the association of IL-10 gene variants with PCOS susceptibility. No allelic nor genetic association were observed between the tested variants and PCOS in Tunisian women, however, a particular IL-10 haplotype with a protective effect for PCOS was identified.

Preeclampsia is associated with reduced renin, aldosterone, and PlGF levels, and increased sFlt-1/PlGF ratio, and specific angiotensin-converting enzyme Ins-Del gene variants.

We investigated the association of angiotensin-converting enzyme (ACE) insertion/deletion (I/D) polymorphism with preeclampsia (PE) in Tunisian women. ACE I/D genotyping was done by PCR in 342 pregnant women with PE and 289 healthy pregnant women. The association between ACE I/D and PE and associated features were also evaluated. Decreased active renin concentration, plasma aldosterone concentration, and placental growth factor (PlGF) were observed in PE cases, while soluble fms-like tyrosine kinase-1 (sFlt-1)/PlGF ratio was significantly higher in the PE group. Distribution of ACE I/D alleles and genotypes were comparable between women with PE and control women. A significant difference in the frequency of the I/I genotype was seen between PE cases and control women according to the recessive model, with a trend towards association in the codominant model. Carriers of the I/I genotype had significantly higher infant birth weights compared to the I/D and the D/D genotype carriers. A dose-dependent relationship was also seen in VEGF and PlGF plasma levels and specific ACE I/D genotypes, with the lowest VEGF levels seen in the I/I genotype carriers compared to the D/D genotype carriers. Similarly, the I/I genotype carriers had the lowest PlGF levels compared to I/D and D/D genotype carriers. Furthermore, when studying the linkage between PE features, we found a positive correlation between PAC and PIGF. Our study suggests a role for ACE I/D polymorphism in the pathogenesis of PE, possibly through modulating VEGF and PlGF levels and infant birth weight, and highlights the relationship between PAC and PlGF.

miR-146a, miR-196a2, miR-499, and miR-149 linked with susceptibility to acute lymphoblastic leukemia: A case-control study in Tunisia.

BACKGROUND: MicroRNAs (miRNAs) are promising biomarkers of hematological malignancies, including acute lymphoblastic leukaemia (ALL). Recent studies revealed that miRNA single nucleotide polymorphisms (miR-SNP) modulate cancer risk by regulating various signaling pathways. However, their association with altered risk of ALL yielded inconsistent results. OBJECTIVE: This study aims to investigate the association of four miR-SNPs with altered risk of ALL risk in Tunisian, the first on North African population. METHODS: A retrospective case-control study exploring the association of miR-146a, miR-196a2, miR-499, and miR-149 SNPs in 126 ALL patients and 126 healthy controls. RESULTS: Of the tested variants, significantly lower minor allele frequencies (MAF) of miR-146a C-allele and higher MAF frequency of miR-149 T-allele (P = 0.006) were seen in ALL cases. The association of miR-149 rs2292832 (Pc = 0.02), but not miR-146a rs2910164 (Pc = 0.11) persisted after correcting for multiple comparisons. Significantly reduced prevalence of miR-146a G/C genotype and higher frequency of miR-149 C/T genotype were seen in ALL cases vs. control subjects, which translated into negative association of miR-146a (rs2910164) with ALL according to the codominant and dominant models. Similarly, miR-149 (rs2292832) was positively associated with ALL according to the codominant and dominant genetic models. Three combinations comprising miR-146a/miR-196a2 GG vs CT + TT genotype combination, miR-146a/miR-499 GG vs TC + CC genotype combination, and miR-146a/miR-149 GG vs CT + TT genotype combination, were less frequent in ALL patients than in controls, and were negatively associated with the presence of ALL. CONCLUSION: Our study suggests that miR-146a and miR-149 polymorphisms constitute biomarkers for personalized diagnosis of ALL.

Association of MMP-2 genes variants with diabetic retinopathy in Tunisian population with type 2 diabetes.

AIMS: Few studies investigated the association of genetic difference in metalloproteinase-2 (MMP-2) gene with diabetic retinopathy but with mixed outcome. To investigate the association between a set of MMP-2 genetic variants and the risk of diabetic retinopathy in an Arab Tunisian population with type 2 diabetes. SUBJECTS AND METHODS: A retrospective case-control study comprising a total of 779 type 2 diabetes patients with or without diabetic retinopathy was conducted. Genotyping was prepared by TaqMan® SNP genotyping qRT-PCR. The variants used were rs243865 (C/T), rs243864 (T/G), rs243866 (G/T) and rs2285053 (C/T). RESULTS: The minor allele frequency (MAF) of the rs243864 MMP-2 variant was significantly higher among diabetic retinopathy patients. Setting homozygous wild type genotype carrier as reference, the rs243864T/G allele was associated with increased risk of diabetic retinopathy under the dominant, recessive, and additive models which persisted when key covariates were controlled for, while a reduced risk of diabetic retinopathy progression was seen after adjustment between non-proliferative and proliferative diabetic patients. Furthermore, the heterozygous genotype GT of the rs243866 variant is positively associated with the risk of proliferative diabetic retinopathy in the additive model. A limited linkage disequilibrium (LD) was revealed between the four-matrix metalloproteinase-2 variants. Four-loci haplotype analysis identified, GCTC, TTTC, and GCTT haplotypes to be positively associated with the risk of diabetic retinopathy. CONCLUSION: Our findings demonstrate that the MMP-2 variant rs243864 and 243866 are related to the susceptibility to diabetic retinopathy and the progression of the disease in an Arab Tunisian population with type 2 diabetes.

Contribution of -1031T/C and -376G/A tumor necrosis factor alpha polymorphisms and haplotypes to preeclampsia risk in Tunisia (North Africa).

Preeclampsia is a gestational disorder characterized by hypertension and proteinuria. Excessive release of pro-inflammatory cytokines, particularly tumour necrosis factor-alpha, has been demonstrated to contribute to endothelial activation and poor trophoblast invasion in placental development, resulting in preeclampsia's clinical symptoms. Genetic polymorphisms of tumour necrosis factor-alpha can regulate its production and may play an important role in the pathogenesis of this disease. This study aimed to evaluate the association of five tumour necrosis factor-alpha gene promoter single nucleotide polymorphisms, or their haplotype combinations, with preeclampsia prevalence. This case-control study was conducted on 300 women with preeclampsia and 300 age-matched women with normal pregnancy from Tunisian hospitals. Genotyping of tumour necrosis factor-alpha -1031 T/C, -376 G/A, -308 G/A, -238 G/A, and +489 G/A SNPs was performed on DNA extracted from blood samples using PCR-restriction fragment-length polymorphism analysis. Statistical analysis was performed using the chi-square test. P < 0.01 were considered statistically significant to take into consideration the multiple comparisons. A significantly higher frequency of the minor allele -1031C (p < 0.001) was observed in preeclampsia cases compared to controls. Notably, the -1031C and -376A (CA) haplotype, which correlates with a higher production of TNF-α protein, had a higher incidence in women with preeclampsia (p = 0.0005). Conversely, the TG haplotype had a low frequency in preeclampsia cases compared to controls (p = 0.002) which suggests that it is associated with a reduced incidence of preeclampsia. These results suggest that tumour necrosis factor-alpha polymorphisms, in particular the -1031C/A, and the haplotype CA, contribute to an increased risk of preeclampsia in Tunisian women.

MMP-2 and MMP-9 Polymorphisms and Preeclampsia Risk in Tunisian Arabs: A Case-Control Study.

The abnormal production of matrix metalloproteinases (MMPs), especially MMP-9 and MMP-2, plays a pivotal role in hypertensive disorders of pregnancy, and as such, can influence the development of preeclampsia. These alterations may result from functional genetic polymorphisms in the promoter region of MMP-9 and MMP-2 genes, which modify MMP-9 and MMP-2 expression. We investigated the association of MMP-9 polymorphism rs3918242 (-1562 C>T) and MMP-2 polymorphism rs2285053 (-735 C>T) with the risk of preeclampsia. This case-control study was conducted on 345 women with preeclampsia and 281 age-matched women with normal pregnancies from Tunisian hospitals. Genomic DNA was extracted from whole blood collected at delivery. Genotypes for -1562 C>T and -735 C>T polymorphisms were performed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). An increased frequency of heterozygous MMP-9 -1562 C/T genotype carriers was observed in women with preeclampsia compared to healthy controls (p = 0.03). In contrast, the MMP-2 -735 C>T polymorphism was not significantly different regarding frequency distribution of the allele and genotype between healthy pregnant women and women with preeclampsia. Our study suggests that the MMP-9 -1562 C/T variant, associated with high MMP-9 production, could be a genetic risk factor for preeclampsia in Tunisian women.

Association of matrix metalloproteinase-2 gene polymorphisms with susceptibility to type 2 diabetes: A case control study.

AIMS: Genetic variations mediating MMP-2 expression may result in individual differences in susceptibility to particular diseases. Our aim was to investigate the possible association of certain MMP-2 gene variants with the susceptibility of type 2 diabetes (T2D) in a Tunisian population. SUBJECTS AND METHODS: A retrospective case-control study involving 310 normoglycemic control subjects and 791 T2D patients was conducted. Genotyping of MMP-2 variants was performed by real time PCR. RESULTS: Minor allele frequencies (MAF) of the rs243865 and the rs243866 MMP-2, were significantly different between T2D cases and controls. Setting homozygous wild-type genotype carrier as reference, a reduced risk of T2D was seen with the rs243865 and the rs243866 genotypes. Haploview analysis revealed limited linkage disequilibrium between the tested MMP-2 and variants, with most haplotypes (99.5%) captured by 7 MMP-2 haplotypes. Taking the GCCC haplotype as reference for MMP-2 (OR = 1.00), a reduced frequency of TTCC haplotypes (P = 0.04) and the GTCC haplotype (P = 3.5 ·â€¯10-5) was noted in T2D which indicates a protective nature of these two haplotypes for T2D development. CONCLUSION: To the best of our knowledge, the present study is the first to demonstrate a consistent association of the rs243865 and rs243866 genotype with a protection for T2D.

Contrasting association of Leptin receptor polymorphisms and haplotypes with polycystic ovary syndrome in Bahraini and Tunisian women: a case-control study.

BACKGROUND: The present study examined the contribution of ethnicity to the association of leptin receptor gene (LEPR) gene variants with polycystic ovary syndrome (PCOS) in Tunisian and Bahraini Arabic-speaking women. METHODS: Subjects consisted of 320 women with PCOS, and 446 eumenorrhic women from Tunisia, and 242 women with PCOS and 238 controls from Bahrain. Genotyping of (exonic) rs1137100 and rs1137101 and (intronic) rs2025804 LEPR variants was done by allelic exclusion. RESULTS: The minor allele frequencies (MAFs) of rs1137100 and rs1137101 were significantly different between PCOS cases and control women from Bahrain but not Tunisia, and LEPR rs1137101 was associated with increased PCOS susceptibility only in Bahraini subjects. Furthermore, rs1137100 was associated with decreased PCOS risk among Bahrainis under codominant and recessive models; rs1137100 was negatively associated with PCOS in Tunisians after controlling for testosterone. In addition, rs2025804 was associated with increased PCOS risk among Tunisian but not Bahraini women, after adjusting for key covariates. Negative correlation was seen between rs1137101 and triglycerides in Tunisians, while homeostasis model assessment of insulin resistance (HOMA-IR) and insulin correlated with rs2025804 and rs1137101 among Bahraini subjects, and rs1137101 correlated with estradiol and prolactin. Taking TAG haplotype as common, positive association of TAA and negative association of TGG haplotype with PCOS was seen among Bahraini women; no three-locus PCOS-associated haplotypes were found in Tunisians. CONCLUSIONS: The present study is the first to demonstrate the contribution of ethnicity to the association of LEPR gene variants with PCOS, thereby highlighting the significance of controlling for ethnicity in gene association investigations.

Increased physical activity is correlated with improved pregnancy outcomes in women with preeclampsia: A retrospective study.

OBJECTIVES: Several studies have focused on the benefits of physical activity to prevent and treat preeclampsia, given that preeclampsia and cardiovascular disease share several risk factors. However, none of these studies have been conducted in Africa. Moreover, it has been demonstrated that exercise training has preventive effects on the development of preeclampsia in mouse models. Therefore, we evaluated the association between the practice of physical activity and the development of this pathology in a Tunisian cohort. STUDY DESIGN: Sixty-one healthy pregnant Tunisian women and 45 women with preeclampsia were recruited and completed the Pregnancy Physical Activity Questionnaire to determine their level and type of physical activity during the entire pregnancy. MAIN OUTCOME MEASURE: Continuous variables were compared using the Mann-Whitney U test, while categorical variables were compared using the Chi-square test. The correlation between preeclampsia features and energy expenditure were assessed using the Pearson's correlation test. RESULTS: Energy expenditure analysis revealed that women with preeclampsia engaged in more sedentary activities than controls, while controls practiced more physical activities. Interestingly, we found a positive correlation between the total amount of energy spent and the duration of pregnancy in controls and women with preeclampsia. CONCLUSIONS: Increasing physical activity is correlated with increasing pregnancy duration which is an index of maternal and fetal health. The practice of physical activities during pregnancy is associated with a healthier pregnancy, while sedentary activities is associated with the development of preeclampsia.

Elevation in Circulating Soluble CD40 Ligand Concentrations in Type 2 Diabetic Retinopathy and Association with its Severity.

BACKGROUND: To investigate the relationship between changes in circulating soluble CD40 ligand (sCD40L) levels and the presence and severity of type 2 diabetic retinopathy (DR). SUBJECTS AND METHODS: sCD40L plasma concentrations were measured in 205 type 2 diabetes (T2DM) patients without DR (DWR; n=50) and with DR (n=155), the latter subdivided into non-proliferative diabetic retinopathy [NPDR; n=98 (63.2%)], or proliferative retinopathy [PDR; n=57 (36.8%)] patients. RESULTS: Receiver operating characteristic analysis provided good discriminatory power for sCD40L as predictor of DR presence, with high sensitivity and specificity. Categorizing DWR and DR patients into sCD40L quartiles, based on sCD40L concentrations in T2DM without DR, demonstrated statistically significant gradual increase in DR risk with increasing sCD40L levels. sCD40L levels were significantly higher in DR compared to DWR patients. Plasma sCD40L levels differed significantly according to DR severity, and correlated with diabetes duration, dyslipedimea, nephropathy, and presence of DR, but not with gender, age, SBP, DBP, FPG, HbA1c, T2DM medications. Linear regression analysis confirmed the association of increased sCD40L levels with DR, independent of others parameters; mean plasma sCD40L levels differing significantly according to DR severity. CONCLUSION: Plasma sCD40L levels were positively associated with DR. The significant finding here is that sCD40L levels can be predictors of DR severity.

Progesterone Receptor (PGR) Gene Variants Associated with Breast Cancer and Associated Features: a Case-Control Study.

Insofar as altered estrogen receptor-progesterone receptor (PR) expression contribute to breast cancer pathogenesis, previous studies examined the association of genetic variation in PR gene (PGR) with breast cancer, but with mixed outcome. We evaluated the association between PGR variants, and breast cancer and associated features. A retrospective case-control study involving 183 female breast cancer patients, and 222 control women. PGR genotyping was done by real-time PCR. Minor allele frequencies of rs1042838, rs590688, and rs10895068 PGR gene polymorphisms were significantly higher in breast cancer patients compared to controls. Patients carrying rs1042838 G/T, rs590688 C/C, and rs10895068 G/A genotypes had higher risk of breast cancer, while carriage of rs3740753 G/G genotype was associated with marginal reduction in breast cancer risk. In addition, carriage of rs1042839, rs3740753, and rs10895068 minor allele was associated with Her2 status, while rs3740753 and rs10895068 were associated with effective hormone replacement therapy. Furthermore, carriage of rs10895068 minor allele in breast cancer women were also associated with age at first pregnancy, hormone receptor (RH) status, and previous use of oral contraceptives. PGR haploview analysis documented moderate-strong linkage disequilibrium (non-random association of alleles at different loci) between 7 of the 8 tested PGR SNPs, thus allowing construction of 7-locus PGR haplotypes. Two haplotypes, ATGCCGA and GTGCCGA, both containing rs590688, were positively associated with breast cancer, thus assigning a breast cancer-susceptible nature to these haplotypes. PGR rs1042838, rs590688, and rs10895068, and ATGCCGA and GTGCCGA haplotypes are related with increased breast cancer susceptibility in Tunisian women.

IKZF1 genetic variants rs4132601 and rs11978267 and acute lymphoblastic leukemia risk in Tunisian children: a case-control study.

BACKGROUND: Associations between IKZF1 gene variants and Acute Lymphoblastic Leukemia (ALL) was recently reported. We examined whether the common IKZF1 polymorphisms rs4132601 T/G and rs111978267 A/G are associated with ALL among a Tunisian pediatric cohort. METHODS: This case-control study involved 170 patients with ALL and 150 control subjects. SNP genotyping was performed by TaqMan® SNP Genotyping Assay. RESULTS: The minor allele G of IKZF1 gene polymorphism rs4132601 T/G was significantly higher in ALL cases than in control subjects (P = 0.029), with 1.54-fold increased risk of ALL. The association of rs4132601 with ALL was seen under co-dominant (P = 0.009), recessive (P = 0.006), and additive (P = 0.027) genetic models, of which the co-dominant (P = 0.027) and recessive (P = 0.027) association remained significant after adjusting for covariates, and False Discovery Rate correction. In contrast, no association was noted for rs111978267 variant. Two-locus (rs4132601-rs11978267) IKZF1 haplotype analysis demonstrated association of GA (P = 0.053), with increased ALL risk [OR (95% CI) = 1.58 (1.00-2.51)], which remained significant after controlling for key covariates [aP = 0.046; aOR (95% CI) = 1.61 (1.01-2.57)]. CONCLUSION: We demonstrated the association of IKZF1 polymorphism rs4132601 T/G with increased risk of ALL among Tunisian pediatric cohort, with altered phenotypic changes among ALL patients.

Circulating leptin concentration, LEP gene variants and haplotypes, and polycystic ovary syndrome in Bahraini and Tunisian Arab women.

BACKGROUND AND AIM: Epidemiological studies suggested that ethnic/racial background influences the associations of altered leptin secretion and leptin gene (LEP) polymorphisms with polycystic ovary syndrome (PCOS). We investigated the association between LEP variants and plasma leptin levels with PCOS in Tunisian and Bahraini Arab women. SUBJECTS AND METHODS: Retrospective case-control study, involving 255 PCOS cases and 253 control subjects from Bahrain, and 320 women PCOS cases and 447 controls from Tunisia. LEP genotyping was done by allele exclusion on real-time PCR. RESULTS: Minor allele frequencies of rs10487506, rs7799039, rs2167270, rs12706832, and rs10954173 LEP variants were not significantly different between PCOS cases and control women among Bahraini and Tunisians, even before applying the Bonferroni correction. Similarly, the genotype distribution of the tested LEP variants was comparable between women with PCOS and control women among Bahraini and Tunisian subjects. None of the tested LEP variants was linked with altered leptin serum concentrations. However, five-locus haplotype analysis identified GGGGG and GAGGG haplotypes to be positively, and haplotype AAGGG to be negatively associated with PCOS in Bahraini women, after adjusting for HOMA-IR. No LEP haplotype associated with PCOS was identified in Tunisians. CONCLUSION: This is the first study to document differential contribution of LEP gene variants with PCOS according to ethnic/racial background of study subjects, highlighting the need for controlling for ethnicity in genetic association studies.

Association of Genetic Variants in NF-kB with Susceptibility to Breast Cancer: a Case Control Study.

Insofar as altered NF-κB signaling stemming from the presence of specific genetic variants in NF-κB gene contribute to cancer pathogenesis, this study evaluated the association between NF-κB rs147574894/I552V, rs148626207/M860T rs3774937 and rs1598859 variants and breast cancer and associated features and complications. This was a retrospective case-control study, which involved 207 women with breast cancer, and 214 cancer-free women who served as controls. NF-κB genotyping was done by real-time PCR. Significantly higher rs3774937 minor allele frequencies (MAF), and lower rs147574894 MAF were seen among breast cancer patients, thereby imparting disease susceptibility and protective nature to these variants, respectively. Significant association of rs3774937 and rs147574894 genotypes with breast cancer was seen under the dominant model. Histological type and grade, molecular type, Her2 positivity and ER+/Her2- correlated positively, while distant metastasis negatively correlated with rs3774937. On the other hand, rs147574894 negatively correlated with histological type and grade, tumor size, Her2 positivity, molecular type, and ER+/Her2-, while rs148626207 correlated positively with histological grade, but negatively with distant metastasis and triple-negative status. Breast cancer-susceptible and -protective 4-locus haplotypes were also identified. This is the first report that addresses the contribution of NF-κB variants to the pathogenesis of breast cancer in Middle Eastern-North African population, and the first to document positive association of rs3774937 with breast cancer.

Impact of obesity on the association of active renin and plasma aldosterone concentrations, and aldosterone-to-renin ratio with preeclampsia.

OBJECTIVE: To evaluate the association of active renin concentration (ARC), plasma aldosterone concentration (PAC) and aldosterone-to-renin ratio (ARR) with the risk of preeclampsia (PE), in particular according to the status of obesity. DESIGN: This retrospective case-control study involved 90 women with PE (mean gestation 35.6 ±â€¯3.6 weeks) and 90 age-matched control women with uncomplicated pregnancies (mean gestation 38.5 ±â€¯2.5 weeks). ARC and PAC were measured by radioimmunoassay; ARR calculated as PAC to ARC ratio. PE cases were stratified into 5 percentiles groups, and analyzed in multivariate logistic regression. RESULTS: Women with PE had significantly lower median ARC and PAC than control women, which were confirmed by percentiles analysis. Spearman correlation demonstrated negative correlation of ARC with body mass index, systolic/diastolic blood pressure. PAC correlated negatively with systolic/diastolic blood pressure, but positively with baby weight, ARC and ARR. On the other hand, ARR positively correlated with BMI and PAC, but negatively with ARC. Lower PAC was associated with PE, irrespective of body weight, while ARC levels were significantly lower in non-obese PE cases vs. control women. ARR was not significantly different between PE cases and control women, when stratified according to obesity. CONCLUSION: Low ARC and PAC in third trimester are more strongly associated with preeclampsia respectively in non-obese and obese women.

Contribution of microRNA-149, microRNA-146a, and microRNA-196a2 SNPs in colorectal cancer risk and clinicopathological features in Tunisia.

BACKGROUND AND AIM: Colorectal cancer (CRC) is a worldwide leading cause of mortality. Genetic studies have associated single nucleotide polymorphisms in genes encoding microRNAs with CRC risk but results are mostly inconclusive across variable ethnicities. In this study, we investigated the association of hsa-mir-149 rs2292832 C/T, hsa-mir-146a rs2910164 G/C and hsa-mir-196a2 rs11614913 C/T and explored their roles in clinicopathological features of CRC progression in an Eastern Tunisian cohort. SUBJECTS AND METHODS: Three hundred thirteen subjects were enrolled in our retrospective study including 152 CRC cases and 161 controls. Genotyping was assayed by RFLP-PCR (Restriction Fragment Length Polymorphism-Polymerase Chain Reaction) method. SPSS v.18.0, R and SNP Stats online software performed statistical analysis. RESULTS: Significantly higher hsa-mir-149C/T rs2292832 minor allele frequency was associated with increased risk of CRC [p = .03; OR = 1.54 (1.08-2.19)]. In addition, significant crude associations of hsa-mir-149C/T rs2292832 polymorphism were detected under codominant, dominant and additive models of inheritance. After adjusting for covariates and performing FDR correction, these associations did not remain. No associations were detected for hsa-mir-146a G/C rs2910164 and hsa-mir-196a2 C/T rs11614913. When performing stratified analysis of clinicopathological features according to genotypes, a significant association (p = .004) was found between hsa-mir-146a G/C rs2910164 and tumour differentiation grade. Regression analysis according to CRC progression features had demonstrated a trend toward significance in overdominant model of inheritance for hsa-mir-149C/T rs2292832 with a protective effect [p = .05; OR = 0.51 (0.26-1.02)]. CONCLUSION: Hsa-mir-149C/T rs2292832 and hsa-mir-146a G/C rs2910164 may influence CRC risk in an ethnicity-dependent manner by interfering with CRC progression parameters in Tunisian cohort.

Association of VEGFA variants with altered VEGF secretion and type 2 diabetes: A case-control study.

BACKGROUND: Vascular endothelial growth factor (VEGF) contributes to type 2 diabetes (T2DM) pathogenesis, and genetic variations in VEGFA gene were suggested to influence VEGF secretion and T2DM pathogenesis. AIM: To evaluate the association of specific VEGFA variants with altered VEGF levels, and with T2DM among Tunisians. SUBJECTS AND METHODS: A retrospective case-control study, performed on 815 T2DM patients, and 805 healthy controls. VEGF levels were measured by ELISA, genotyping of VEGFA variants was done by allelic exclusion method (real-time PCR). RESULTS: MAF of rs1570360, rs2010963, rs25648, rs833068, rs3025036, and rs3025039 were significantly different between T2DM cases and controls. Increased T2DM risk was associated with rs699947, rs1570360, and rs3025020, while reduced T2DM risk was seen with rs1547651, rs2010963, rs25648, rs3025036, and rs3025039 genotypes, thus assigning T2DM susceptibility and protection, respectively. Reduced VEGF levels were associated with rs833061, rs2010963, and rs3025039 heterozygosity and rs3025036 major allele homozygosity in T2DM cases, while increased VEGF levels were seen in rs833070 homozygous major allele genotype. Both rs699947 and rs1570360 positively, while rs2010963 and rs3025036 negatively correlated with fasting glucose. In addition, rs699947 positively correlated with LDL-cholesterol, and rs3025039 positively correlated with diabetes duration, but negatively with HbA1c and serum triglycerides. Haploview analysis identified Block 1 containing 8 loci, and Block 2 with the remaining 3 loci. Haplotypes ACTGCCGG and AACGGCGA (Block 1) were negatively associated with T2DM, while haplotype CCC was positively and haplotype CGC (Block 2) were negatively associated with T2DM. CONCLUSION: This study confirms the contribution of altered VEGF secretion, resulting from genetic variation in VEGFA gene into T2DM pathogenesis, hence supporting role for VEGFA as T2DM candidate locus.

Differential association of ESR1 and ESR2 gene variants with the risk of breast cancer and associated features: A case-control study.

BACKGROUND: Estrogen is key to breast cancer pathogenesis, and acts by binding its receptor (ER), which exists as ERα and ERß, encoded by ESR1 and ESR2 genes, respectively. Studies that investigated the association of ESR1 and ESR2 variants with breast cancer yielded mixed outcome, and ethnic contribution was proposed. We evaluated the association between ESR1 and ESR2 variants and breast cancer and associated features in Tunisian women. METHODS: Retrospective case-control study involving 207 female breast cancer patients, and 284 control women. Genotyping was done by real-time PCR. RESULTS: Minor allele frequencies (MAF) of tagging SNPs rs2234693 and rs3798577 (ESR1) were significantly higher, while MAF of rs1256049 (ESR2) was significantly lower in breast cancer patients vs. CONTROLS: Patients carrying rs3798577 genotypes had higher risk, while rs1256049 genotype carriers had reduced risk of breast cancer. The association of ESR1 and ESR2 gene variants with breast cancer depended on ER and Her-2 status. ESR1 rs3798577 and ESR2 rs1256049 were associated with breast cancer in ER-positive cases, and ESR1 rs2234693, and rs3798577 were associated with breast cancer in Her-2-negative cases, while the association of ESR2 rs1256049 with breast cancer was seen in Her-2 positive cases. Haploview analysis identified 4-locus ESR1 haplotypes that were positively (CGTT, TACC, and TACT), and negatively (CGTC) associated with breast cancer. No ESR2 haplotypes associated with breast cancer were identified. CONCLUSION: ESR1 alleles and genotypes, and specific 3-locus ESR1 haplotypes are related with increased breast cancer susceptibility in Tunisian women. However, ESR2 variant and specific 1-locus ESR1 haplotype have a protective effect.

Differential association of DENND1A genetic variants with polycystic ovary syndrome in Tunisian but not Bahraini Arab women.

BACKGROUND AND AIM: Polycystic ovary syndrome (PCOS) is a common endocrine disorder, and results from interaction between modifiable and non-modifiable factors, including genetic predisposition. Previous genome-wide association studies and meta-analysis identified DENND1A as PCOS susceptibility locus in some, but not all populations. We investigated whether the association of DENND1A gene variants with PCOS was similar between Tunisian and Bahraini Arab women. SUBJECTS AND METHODS: This was retrospective case-control study. Study subjects comprised 320 women with PCOS, and 446 age-and ethnically-matched control women. Genotyping of DENND1A rs10818854, rs2479106, and rs10986105 variants was done by real-time PCR. RESULTS: Minor allele frequency of rs10818854 and rs10986105 DENND1A variants were significantly higher among women with PCOS. Setting homozygous wild-type genotype carrier as reference, rs10818854 and rs10986105 were associated with increased risk of PCOS, which persisted after controlling for key covariates, while reduced PCOS risk was seen with only rs2479106 under the additive model. This assigned PCOS susceptibility and protective nature to these genotypes, respectively. Both rs10818854 and rs10986105 were positively associated with HOMA-IR and AMH in women with PCOS. Haploview analysis revealed limited linkage disequilibrium between the tested DENND1A variants. Extensive diversity in haplotypes assignment was seen, with most haplotypes (99.5%) captured by 5 haplotypes. Taking GAT haplotype as reference, AAG, and GAG haplotypes were positively, while GAT haplotype was negatively associated with PCOS. CONCLUSION: The association of DENND1A rs10818854 and rs10986105 variants with PCOS in Tunisian but not Bahraini women confirms the dependence of this association on the ethnic/racial origin of study subjects.

Contribution of angiotensinogen M235T and T174M gene variants and haplotypes to preeclampsia and its severity in (North African) Tunisians.

BACKGROUND: Preeclampsia (PE) is a pregnancy-associated hypertensive disorder and a leading cause of maternal and neonatal morbidity and mortality. While its pathogenesis remains ill defined, several candidate genes for PE have been identified, but results remain inconclusive. We investigated the association of the angiotensinogen ( AGT) gene variants M235T and T174M with PE, and we analyzed the contribution of both variants to the severity of PE. METHODS: This case-control study enrolled 550 Tunisian pregnant women: 272 with PE, of whom 147 presented with mild, and 125 with severe PE, along with 278 unrelated age- and ethnically matched control women. AGT genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism. RESULTS: Significantly higher M235T minor allele frequency (MAF) was associated with increased risk of PE ( p < 0.001). Decreased frequency of heterozygous T174M genotype carriers were found in control women ( p = 0.015), suggesting a protective effect of this genotype (odds ratio (95% confidence interval) = 0.51 (0.29-0.89)). Two-locus haplotype analysis demonstrated MM and TT haplotypes to be negatively and positively associated with PE, respectively. MAF of M253T, but not T174M, was higher in the severe PE group, and carrying M235T or T174M minor allele was associated with increased body mass index ( p < 0.001) among unselected PE women. CONCLUSIONS: AGT M235T and T174M variants contribute to an increased risk of developing PE, and for M235T to PE severity.