Implication of genetic variation at the promoter and exon1 of UGT1A1 in occurrence of cholelithiasis in Tunisia.

International audienceBilirubin is conjugated with glucoronic acid in the liver by UDP-glucuronosyltransferase 1A1 (UGT1A1). Polymorphisms at the promoter region or exon1 of UGT1A1 gene result in unconjugated hyperbilirubinemia and could be at the origin of gallstone formation. The purpose of this study is to determine whether polymorphisms in the promoter area and exon 1 of UGT1A1 can be considered as a risk factor for lithogenesis. Our study involved 76 patients with cholelithiasis as well as 141 unaffected subjects. For each subject an analysis of the bilirubin parameters was performed. We screened genetic variation in the promoter and exon1 UGT1A1 namely the A (TA) nTAA and the six following SNPs: 44T>G, 101C>A, 115C>G, 145C>T, 211G>A and 222 C>A by PCR/sequencing. Our findings show that subjects with (TA)(7) or (TA)(8) variant in their genotypes are associated with high bilirubin level. Furthermore, the comparison between patients and controls according to A(TA)nTAA variation demonstrated that (TA)(6)/(TA)(7) and (TA)(7)/(TA)(7) genotype and (TA)(7) and (TA)(8) alleles were significantly associated with an increased risk of gallstone diseases p=0.0017, p= 6.1 10(-6), p=1.5 10(-6) and p=0.025 respectively. However, polymorphisms in exon1 were normal in all studied subjects except for the 211G>A which appears to be associated with a protective effect p=7.910(-9); OR=0.03, CI95% (0.001-0.158)

rs11886868 and rs4671393 of BCL11A associated with HbF level variation and modulate clinical events among sickle cell anemia patients

International audienceAims: Fetal hemoglobin (HbF) modulates the phenotype of sickle cell anemia (SCA) by inhibiting deoxy sickle hemoglobin (HbS) polymerization. HbF genes are genetically regulated, and the level of HbF and its distribution among sickle erythrocytes is highly variable. Herein, we aimed to determine whether two functional polymorphisms of BCL11A are implicated in the variation of HbF and clinical events in SCA Tunisian patients. Material and methods: The studied population consisted of 148 SCA patients with SS phenotype. The group of patients was divided into two subgroups according to the threshold point of %HbF which is 15%. Genotyping of rs11886868 and rs4671393 was performed using PCR/Sequencing. To test for trait association with the candidate SNPs, genotype and allele frequencies between `group who had %HbF 15' (controls) were compared using Pearson's chi-square test (compare 2, version 1.02). The association of each genotype and the combined genotype with complications was performed by logistic regression test. Results: Our findings showed that the majority of patients carried genotype CT of rs11886868 and genotypes AG and GG of rs4671393 present HbF level < 15%. RR = 0.08, RR = 0.176, and RR = 0.189, respectively. The results showed a significant association between the alleles T of rs11886868 and G of rs4671393 and %HbF < 15% with P = 0.016; RR = 0.39 and P = 8.9 x 10(-3): RR = 0.567, respectively. Interestingly, the C allele of the rs11886868 and the A allele of the rs46713939 were associated with an ameliorated phenotype in patient's SCA. The combination of the genotypes GG and CT explains more phenotypic variance than the sum of the two BCL11A SNPs taken individually

Association of rs1319868, rs1567811 and rs8041224 of gene with infection among sickle cell anemia Tunisian patients

Background and aimSickle cell anemia (SCA) is characterized by variable patterns of clinical expression. Polymorphisms linked to different genes have been associated with specific complications of the disease. Herein, we focused on the study of the association of 4 polymorphisms of Insulin like Growth Factor 1 receptor (IGF1R) gene with infections, which are the major cause of death in SCA.Material and methodsThis study involved 116 sickle cell patients among whom 58 SS have the same confirmed infectious phenotype. Allele-Specific PCR was performed for the study of rs1319868, whereas the PCR/sequencing method was carried out for rs1567811, rs2872060 and rs8041224.ResultsThe results showed that rs1319868 and rs1567811 were associated with a decreased risk of infection among SS patients (p=0.038, RR=0.54; p=0.044, RR=0.56, respectively). Interestingly, the combination of different genotypes showed the association of the genotype GT of rs1319868 and the genotype CC of rs8041224 with further decreased infection risk in SCA (p=0.028, RR=0.04).ConclusionThese significant associations of IGF1R SNPs with infection suggest that this gene could play an important role in the immune function in SCA

Association of Lymphotoxin Alpha Polymorphism with Type 1 Diabetes in a Tunisian Population

International audienceWe investigated the association of the lymphotoxin (LT)-alpha gene polymorphism +249A/G with type 1 diabetes. The distribution of genotypes of the LT-alpha +249A/G single nucleotide polymorphism (SNP) was assessed in 115 diabetic patients and 123 normoglycemic control subjects, using PCR-restriction fragment length polymorphism analysis. Among unselected patients, the SNP was significantly associated with increased risk of diabetes (chi(2) = 8.44, p = 0.014) and was found to be more pronounced among female (chi(2) = 8.37, p = 0.02) than male (chi(2) = 6.11, p = 0.047) patients. A significant association was detected between LT-alpha +249A/G and increased risk of diabetes, in particular for young-onset patients (chi(2) = 6.92, p = 0.031). Moreover, we reported significant differences in levels of HbA1c, triglycerides, alanine transaminase, and anti-glutamic acid decarboxylase-65 among alleles. Additional studies with extended patient age groups and different ethnicities are needed to confirm our findings

Two new class III G6PD variants [G6PD Tunis (c.920A>C: p.307Gln>Pro) and G6PD Nefza (c.968T>C: p.323 Leu>Pro)] and overview of the spectrum of mutations in Tunisia.

We screened 423 patients referred to our laboratory after hemolysis triggered by fava beans ingestion, neonatal jaundice or drug hemolysis. Others were asymptomatic but belonged to a family with a history of G6PD deficiency. The determination of enzymatic activity using spectrophotometric method, revealed 293 deficient (143 males and 150 females). The molecular analysis was performed by a combination of PCR-RFLP and DNA sequencing to characterize the mutations causing G6PD deficiency. 14 different genotypes have been identified : G6PD A(-) (376A>G;202G>A) (46.07%) and G6PD Med (33.10%) were the most common variants followed by G6PD Santamaria (5.80%), G6PD Kaiping (3.75%), the association [c.1311T and IVS11 93c] (3.75%), G6PD Chatham (2.04%), G6PD Aures (1.70%), G6PD A(-) Betica (0.68%), the association [ 376G;c.1311T;IVS11 93c] (0.68%), G6PD Malaga, G6PD Canton and G6PD Abeno respectively (0.34%). Two novel missense mutations were identified (c.920A>C: p.307Gln>Pro and c.968T>C: p.323 Leu>Pro). We designated these two class III variants as G6PD Tunis and G6PD Nefza. A mechanism which could account for the defective activity is discussed

Hb A 2 -Pasteur-Tunis [δ59(E3)Lys→Asn, AA G →AA C ]: A New δ Chain Variant Detected by DNA Sequencing in a Tunisian Carrier of the Codon 39 (C→T) β 0 -Thalassemia Mutation

International audienceWe describe a new delta-globin variant, Hb A(2)-Pasteur-Tunis [delta 59(E3)Lys -> Asn, AAG -> AAC]. This hemoglobin (Hb) displayed an electrophoretic mobility faster than normal Hb A(2) and was expressed at 2.2%. The molecular defect was characterized, by DNA sequencing and confinned by a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP)-designed protocol. Hb A(2)-Pasteur-Tunis was found in a carrier of a codon 39 (C -> T) beta(0)-thalassemia (thal), presenting with a normal Hb A(2) level. Phenotype and genotype investigations revealed that the total Hb A(2) level of the patient was that expected for a minor beta-thal (4.8%)

Two new β + -thalassemia mutation [ β -56 (G → C); HBBc. −106 G → C ] and [ β −83 (G → A); HBBc. −133 G → A ] described among the Tunisian population

International audienceObjectivesDifferent thalassemia mutations have been reported in various ethnic groups and geographical regions in Tunisia. In the present study, we have investigated two rare beta(+)-thalassemia mutations, that have not previously been reported in the Tunisian population [beta -56 (G>C); HBBc. -106 G>C] and [beta -83 (G>A); HBBc. -133 G>A]. MethodsThe whole beta-globin gene was directly sequenced, and haplotype analysis was conducted through a PCR/RFLP method. Results: Two new mutations were identified for the first time in Tunisia. They are located within the promoter region of beta-globin gene at position -56 (G>C) and -83 (G>A). Linkage analysis using beta-globin gene cluster haplotypes showed that these two mutations were associated with Mediterranean beta-haplotype IX [-+-++++] and framework 2 (FW2) [CCTCT]. ConclusionsThe two newly described mutations lead to the beta(+)-thalassemia among Tunisian patients. The haplotype analysis and framework assignment have helped to identify the chromosomal background associated with these mutations, and determine their origin and spread. Am. J. Hum. Biol. 27:716-719, 2015. (c) 2015 Wiley Periodicals, Inc

Haplotype Map of Sickle Cell Anemia in Tunisia

-Globin haplotypes are important to establish the ethnic origin and predict the clinical development of sickle cell disease patients (SCD). To determine the chromosomal background of Tunisian sickle cell patients, in this first study in Tunisia, we have explored four polymorphic regions of -globin cluster on chromosome 11. It is the 5 region of -LCR-HS2 site, the intervening sequence II (IVSII) region of two fetal ( G and A ) genes and the 5 region of -globin gene. The results reveal a high molecular diversity of a microsatellite configuration describing the sequences haplotypes. The linkage disequilibrium analysis showed various haplotype combinations giving 22 &quot;extended haplotypes&quot;. These results confirm the utility of the -globin haplotypes for population studies and contribute to knowledge of the Tunisian gene pool, as well as establishing the role of genetic markers in physiopathology of SCD