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Laouini N.,Research Laboratory LR00SP03 | Bibi A.,Research Laboratory LR00SP03 | Ammar H.,Research Laboratory LR00SP03 | Kazdaghli K.,Childrens Hospital | And 12 more authors.
Molecular Biology Reports | Year: 2013

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common human enzyme defect. In this study, we aimed to perform a molecular investigation of G6PD deficiency in Tunisia and to associate clinical manifestations and the degree of deficiency with the genotype. A total of 161 Tunisian subjects of both sexes were screened by spectrophotometric assay for enzyme activity. Out of these, 54 unrelated subjects were selected for screening of the most frequent mutations in Tunisia by PCR/RFLP, followed by size-based separation of double-stranded fragments under non-denaturing conditions on a denaturing high performance liquid chromatography system. Of the 56 altered chromosomes examined, 75 % had the GdA- mutation, 14.28 % showed the GdB- mutation and no mutations were identified in 10.72 % of cases. Hemizygous males with GdA- mutation were mostly of class III, while those with GdB- mutation were mainly of class II. The principal clinical manifestation encountered was favism. Acute hemolytic crises induced by drugs or infections and neonatal jaundice were also noted. Less severe clinical features such as low back pain were present in heterozygous females and in one homozygous female. Asymptomatic individuals were in majority heterozygote females and strangely one hemizygous male. The spectrum of mutations seems to be homogeneous and similar to that of Mediterranean countries; nevertheless 10.72 % of cases remain with undetermined mutation thus suggesting a potential heterogeneity of the deficiency at the molecular level. On the other hand, we note a better association of the molecular defects with the severity of the deficiency than with clinical manifestations. © 2012 Springer Science+Business Media Dordrecht. Source

Sahli C.A.,Research Laboratory LR00SP03 | Gritli S.,Charles Nicolle Hospital | Dabboubi R.,Research Laboratory LR00SP03 | Omar S.,Laboratory of Biochemistry | And 4 more authors.
Annales de Biologie Clinique | Year: 2015

The most common inherited haemoglobin disorders encountered in Tunisia are β-thalassemia and sickle cell disease, which result from mutations in the β-globin gene. Few studies focused on δ-globin gene variations responsible for δ-thalassemia or HbA2 variants. HbA2' [δ16 (A13) Gly→Arg (GGC→CGC)] is a δ-chain variant that has been identified in several populations of African origin. We report herein for the first time the description of HbA2' in the Tunisian population. Identification of HbA2' in the studied family was carried out by high-performance liquid chromatography and confirmed by sequencing analyses of the whole δ-globin gene. Haplotypes of the β-globin gene cluster were constructed by mapping the restriction sites using polymerase chain reaction followed by enzymatic digestion. Compound heterozygosity of HbA2' with HbO-Arab was identified in the proband. The mother and two other siblings showed heterozygous HbA2' whereas the father showed heterozygous HbO-Arab. The sum of HbA2 and HbA2' in all cases was less than 4%, thus excluding β-thalassemia. β-cluster haplotype analysis revealed that this mutation was associated with the F haplotype (-+-+++). The unique origin of this mutation in Africa is likely since the linked β-cluster haplotype is one of the major haplotypes found in African populations. © 2015, John Libbey Eurotext. All rights reserved. Source

Sahli C.A.,Research Laboratory LR00SP03 | Bibi A.,Biochemistry Laboratory | Ouali F.,Research Laboratory LR00SP03 | Fredj S.H.,Research Laboratory LR00SP03 | And 11 more authors.
Clinical Chemistry and Laboratory Medicine | Year: 2013

Background: In Tunisia, thalassemia and sickle cell disease (SS) represent the most prevalent monogenic hemoglobin disorders with 2.21% and 1.89% of carriers, respectively. This study aims to evaluate the diagnosis reliability of 12 red blood cell (RBC) indices in differentiation of β-thalassemia trait (β-TT) from iron deficiency anemia (IDA) and between homozygous SS and sickle cell thalassemia (ST). Methods: The study covered 384 patients divided into three groups. The first one is composed of 145 control group, the second consists of 57 β-TT and 52 IDA subjects and the last one with 88 SS and 42 ST patients. We calculated sensitivity, specificity, positive-predictive values, negative-predictive values, percentage of correctly identified patients and Youden's Index (YI) for each indice. We also established new cut-off values by receiver operating characteristic curves for each indice. An evaluation study was performed on another population composed of 106 β-TT, 125 IDA, 31 SS, and 17 ST patients. Results: Srivastava Index (SI) shows the highest reliability in discriminating β-TT from IDA at 5.17 as a cut-off and also SS from ST with 7.7 as another threshold. Mentzer Index (MI) and RBC appear also useful in both groups with new cut-offs slightly different from those described in literature for β-TT and IDA. Conclusions: The effectiveness and the simplicity of calculation of these indices make them acceptable and easy to use. They can be relied on for differential diagnosis and even for diagnosis of β-TT with atypical HbA2 levels. © 2013 by Walter de Gruyter Berlin Boston 2013. Source

Haloui S.,Research Laboratory LR00SP03 | Laouini N.,Research Laboratory LR00SP03 | Sahli C.A.,Research Laboratory LR00SP03 | Daboubi R.,Research Laboratory LR00SP03 | And 14 more authors.
Annales de Biologie Clinique | Year: 2016

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common enzymopathy. More than 200 mutations in the G6PD gene have been described. In Tunisia, the A-African and the B-Mediterranean mutations predominate the mutational spectrum. The purpose of this study was to apply the amplification refractory mutation system (ARMS-PCR) to the identification of Gd A+, Gd A-and Gd B-variants in a cohort of deficient individuals and to establish a phenotype/genotype association. 90 subjects were screened for enzymatic deficiency by spectrophotometric assay. The molecular analyses were performed in a group of 50 unrelated patients. Of the 54 altered chromosomes examined, 60% had the Gd A-mutation, 18% showed the Gd Bmutation and in 20% of cases, no mutations have been identified. The ARMSPCR showed complete concordance with the endonuclease cleavage reference method and agreed perfectly with previous Tunisian studies where Gd A-and Gd B-were the most encountered. Also, similarities in spectrum mutations with North African and Mediterranean countries suggest gene migration from Africa to Europe through Spain. In conclusion, ARMS has been introduced in this study for common G6PD alleles identification in Tunisia. It gives some advantages compared to the traditional endonuclease digestion method since it is more convenient and timesaving and also offers the possibility to be applied in mass screening surveys. Copyright © 2016 JLE. Source

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