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.

Association of estrogen receptor gene variants (ESR1 and ESR2) with polycystic ovary syndrome in Tunisia.

SNV (single nucleotide variation) in estrogen receptor (ESR1 and ESR2) genes are susceptibility markers for complex diseases, such as cancer, metabolic disorders and women infertility. We explored six widely used SNVs in ESR1 (rs2234693, rs9340799, rs3798577, rs3020314) and ESR2 (rs1256049, rs4986938) in polycystic ovary syndrome (PCOS) in women from Tunisia (n = 254) compared to controls (n = 170). Genotyping was performed by RFLP-PCR or real-time PCR and analyzed in GoldenHelix statistical package. Logistic regression revealed association of rs2234693, rs3798577 and rs3020314 (ESR1) and rs1256049 (ESR2), the association of rs2234693 (C/T) being the strongest with P < 4.81 × 10-6, 2.88 × 10-5 after Bonferroni correction, OR 0.31, 95%CI (0.18-0.53)). Correlations were found with LH, LH/FSH or hyperandrogenism and even more significant with metabolic syndrome (rs9340799) and hyperglycemia (rs3798577). Among 14 haplotypes reconstructed in ESR1gene, four haplotypes (H1 to H4) were associated with PCOS the strongest being that of H1 (P < 0.002) supported by Bonferroni (P < 0.033) and permutation tests (P < 4 x10-4). In haplotype trend regression, concordant correlations were found with insulin resistance (P < 0.033) for H2 and with high blood pressure for H3 (P < 0.048). While these data revealed influential role on metabolic rather and hormonal features of PCOS, the association of rs2234693 was the strongest among all ethnic populations studied thus far giving a new insight on estrogen receptor gene variation in distant North African populations and their role in metabolic alteration of PCOS.

Vascular endothelial growth factor (VEGFA) gene variation in polycystic ovary syndrome in a Tunisian women population.

BACKGROUND: Polycystic ovary syndrome (PCOS) is characterized by the growth of a number of small cysts on the ovaries which leads to sex hormonal imbalance. Women who are affected by this syndrome suffer from irregular menstrual cycles, decline in their fertility, excessive hair growth, obesity, acne and most importantly cardiac function problems. The vascular endothelial growth factor (VEGF) plays a pivotal role in tissue vascularization in general and in the pathogenesis of many diseases. The PCOS was found to be associated with high expression levels of VEGF. In women who undergo assisted reproductive procedures (ART), VEGF was found to be a key mediator of other factors to control ovary angiogenesis. Here, we set out to examine the association of VEGFA gene polymorphism with PCOS and its components in a population of Tunisia women to enhance our understanding of the genetic background leading angiogenesis and vascularization abnormalities in PCOS. METHODS: The association of VEGFA gene with PCOS and its components was examined in a cohort of 268 women from Tunisia involving 118 PCOS patients and 150 controls. VEGFA gene variations were assessed through the analysis of the following SNPs rs699947 (A/C), rs833061 (C/T), rs1570360 (G/A), rs833068 (G/A), rs3025020 (C/T), and rs3025039 (C/T). The linkage disequilibrium between SNPs was assessed using HAPLOVIEW software while combination of SNPs into haplotypes in the population and the reconstruction of the cladogram were carried-out by PHASE and ARLEQUIN programs, respectively. Genetic association and genotype-phenotype correlations were calculated by logistic regression and non-parametric tests (Kruskall-Wallis and Mann-Whitney tests), respectively, using StatView program. RESULTS: We observed 10 haplotypes in our studied cohort whereH1 (ACGG), H2 (ACAG), H7 (CTGG) and H8 (CTGA) were the most frequent. We observed the association of the genotype CT of the SNP rs30225039 with PCOS phenotype (P = 0.03; OR 95 % CI = 2.05 [1.07-3.90]) and a trend for correlation of the pair of haplotypes H2/H2 with prolactin levels in plasma (P = 0.077; 193.5 ± 94.3 vs 45.7 ± 7.2). These data are consistent with literature and highlight one more time the role of vascularization in the pathogeny of PCOS. CONCLUSIONS: LD pattern in VEGF locus showed a similar LD pattern between the Tunisian population and the CEU. More haplotypes in the Tunisian population than in CEU was observed (22 haplotypes vs 16 haplotypes) suggesting higher recombination rate in Tunisians. The study showed that there was any advantage of using haplotypes compared with SNPs taken alone.

Haplotyping strategy highlights the specificity of FTO gene association with polycystic ovary syndrome in Tunisian women population.

The FTO (fat mass and obesity associated) gene was associated with different metabolic disorders in populations from different origins but with great difference between African and non-African populations. North-African populations combine many genetic backgrounds, among which African, Berber and Caucasian components, which makes North-Africans a good model for studying the genetic association of FTO. In the present investigation we explored the association of FTO gene with polycystic ovary syndrome (PCOS) in a population from Tunisia (n=278). Single nucleotide polymorphisms (SNPs) used in this study were previously associated in non-African populations: rs8050136 (A/C), rs9939609 (A/T), rs9930506 (G/A), or in both African and non-African populations: rs8057044 (A/G). Genotyping was performed by allelic discrimination method on StepOne real-time PCR system or KASPar technology. Linkage disequilibrium (LD) pattern was assessed by HAPLOVIEW and reconstruction of haplotypes was performed by PHASE, while statistical analyses were performed using StatView and GoldenHelix programs. Among the 13 haplotypes in the population, three (h1, h7 and h13) were strongly associated with PCOS notably h13 (P<0.0001, OR95%CI=0.040 [0.005-0.294]) while SNPs display weaker association. Moreover the LD pattern in FTO in the Tunisian population (r(2) index) was intermediary between those of Caucasian and Africans. This highlights the need for studying the genetics of complex disorders in the North-African populations taking into-account the haplotype structure of candidate loci more than SNPs taken alone.

Common polymorphisms of calpain-10 and the risk of polycystic ovary syndrome in Tunisian population: a case-control study.

Recent studies have suggested that calpain-10 (CAPN10) gene polymorphisms play a role in the susceptibility to polycystic ovary syndrome (PCOS). The aim of the present study was to evaluate the possible association between three single nucleotide polymorphisms (SNPs) in CAPN10 gene: UCSNP-43 (rs3792267), UCSNP-19 (rs3842570), and UCSNP-63 (rs5030952) and PCOS in Tunisian cases and control women. Study subjects included 127 women with PCOS (mean age 29.8 ± 4.7 year) and 150 healthy women (mean age 33.5 ± 5.6 year). CAPN10 genotyping was carried-out by direct PCR and PCR-RFLP. Linkage disequilibrium pattern in the genomic region explored was determined by HAPLOVIEW 4.2 while reconstruction of haplotypes was done using PHASE 2.1. The phylogenetic distribution of haplotypes in the population was determined by ARLEQUIN 2.000. Six haplotypes were observed. None of SNPs associated with PCOS or its components while the haplotype H4 associated with the phenotype PCOS-obese (P < 0.025). Moreover the pair of haplotypes H1/H4 strongly associated with high blood-pressure (OR = 14.4, P < 0.012). This work confirms the association of CAPN10 gene with metabolic components in PCOS and highlights the role of haplotypes as strong and efficient genetic markers.