Salima Ferchichi

Gaucher Disease: Clinical, Biological and Therapeutic Aspects.

We present a brief review of Gaucher disease (GD), the most common lysosomal storage disease. GD is a rare autosomal recessive disorder characterized by the defective function of the catabolic enzyme β-glucocerebrosidase (GBA), leading to an accumulation of its substrate, glucocerebroside. Clinical signs and symptoms include neurological dysfunctions, bone infarcts and malformations, hepatosplenomegaly and hypersplenism leading to anemia, neutropenia and thrombocytopenia. Enzyme replacement therapy with recombinant GBA is the mainstay of treatment for GD, which became the first successfully managed lipid storage disease. Future treatments may include oral enzyme replacement and/or gene therapy interventions.

Mucopolysaccharidosis type I: molecular characteristics of two novel alpha-L-iduronidase mutations in Tunisian patients.

BackgroundMucopolysaccharidosis type I (MPS I) is an autosomal storage disease resulting from defective activity of the enzyme α-L-iduronidase (IDUA). This glycosidase is involved in the degradation of heparan sulfate and dermatan sulfate. MPS I has severe and milder phenotypic subtypes.Aim of study: This study was carried out on six newly collected MPS I patients recruited from many regions of Tunisia.Patients and methods: Mutational analysis of the IDUA gene in unrelated MPS I families was performed by sequencing the exons and intron-exon junctions of IDUA gene.ResultsTwo novel IDUA mutations, p.L530fs (1587_1588 insGC) in exon 11 and p.F177S in exon 5 and two previously reported mutations p.P533R and p.Y581X were detected. The patient in family 1 who has the Hurler phenotype was homozygous for the previously described nonsense mutation p.Y581X.The patient in family 2 who also has the Hurler phenotype was homozygous for the novel missense mutation p.F177S. The three patients in families 3, 5 and 6 were homozygous for the p.P533R mutation. The patient in family 4 was homozygous for the novel small insertion 1587_1588 insGC. In addition, eighteen known and one unknown IDUA polymorphisms were identified.ConclusionThe identification of these mutations should facilitate prenatal diagnosis and counseling for MPS I in Tunisia.BackgroundMucopolysaccharidosis type I (MPS I) is an autosomal recessive lysosomal storage disorder caused by the deficient activity of the enzyme of α-L-iduronidase (IDUA, EC 3.2.1.76). This glycosidase is involved in the degradation of heparan sulfate and dermatan sulfate. The clinical phenotype of MPS I ranges from the very severe in Hurler syndrome (MPS IH) to the relatively benign in Scheie syndrome (MPS IS), with an intermediate phenotype designated Hurler/Scheie (MPS IH/S) [1]. Isolation of complementary and genomic DNAs encoding human α -L- iduronidase [2, 3] have enable the identification of mutations underlying the enzyme defect and resulting in MPS I clinical phenotype. More than 100 mutations have been reported in patients with the MPS I subtypes (Human Gene Mutation Database; http://www.hgmd.org). High prevalence of the common mutations p.W402X and p.Q70X has been described; both of them in the severe clinical forms [4, 5]. A high prevalence of common mutation p.P533R has also been described in MPS I patients with various phenotypes [5, 6]. In addition, rare mutations including single base substitution, deletion, insertion and splicing site mutation have been identified [7], indicating a high degree of allelic heterogeneity in IDUA gene.Here, we described two novel IDUA mutations in MPS I Tunisian patients. These lesions were homoallelic in all the patients of the six families investigated as consanguineous marriages are still frequent in Tunisia [8].

Molecular analysis of mucopolysaccharidosis type I in Tunisia: identification of novel mutation and eight Novel polymorphisms

Mucopolysaccharidosis type I (MPS I) is an autosomal recessive lysosomal storage disorder caused by a genetic defect in alpha-L-iduronidase (IDUA) which is involved in the degradation of dermatan and heparan sulfates. The disease has severe and milder phenotypic subtypes. The aim of this study was the detection of mutations in the IDUA gene from 12 additional MPS I patients with various clinical phenotypes (severe, 8 cases; intermediate, 3 cases; mild, 1 case).Patients and methodsIn this study, the IDUA mutations in eight unrelated Tunisian families were performed by amplifying and sequencing the IDUA exons and intron-exon jonctions.ResultsFive IDUA mutations were detected: one is the L578Q, a novel mutation found, in milder patient. The others were the previously described: P533R, Y581X, F602X and R628X that produce a severe and intermediate phenotype. In addition, eighteen variants, including eight previously unreported polymorphisms (IVS6+21c > a, IVS7+79c > t, IVS7-45 g > c, IVS9+36t > c, IVS10+140c > a, IVS11+33c > t, IVS12+13c > t and IVS12-31c > g), were detected.ConclusionThis paper, showed a heterogeneous pattern of mutations and polymorphisms among Tunisian patients.

Clinical Utility of Serum Cystatin C in Predicting Coronary Artery Disease in Patients Without Chronic Kidney Disease

Cystatin C has been proposed as a novel marker of renal function and predictor of cardiovascular risk. The aim of this study was to investigate the role of cystatin C level as a predictor of cardiovascular events in patients with coronary artery disease (CAD).

Low erythrocyte catalase enzyme activity is correlated with high serum total homocysteine levels in Tunisian patients with acute myocardial infarction.

BackgroundAn imbalance between pro-oxidants and antioxidant systems has been suggested to be implicated in the physiopathology of acute myocardial infarction (AMI). We aimed to evaluate the antioxidant capacity in Tunisian patients and to assess the possible relationship between erythrocyte catalase enzyme activity and hyperhomocysteinaemia.Methods108 patients with AMI and 81 healthy subjects were enrolled in this study. Catalase erythrocyte enzyme activity was determined spectrophotometrically whereas “total antioxidant status” (TAS) concentration was measured by a commercially available method. Serum total homocysteine (tHcy) level was determined by a fluorescence polarization immunoassay (FPIA). Lipid peroxidation was measured with a fluorimetric method as “thiobarbituric acid reactive substances” (TBARS).ResultsCompared with healthy subjects, patients with AMI had significantly lower catalase activity (P<0.001), TAS concentrations (P<0.001), and significantly higher serum tHcy (P<0.001) and TBARS levels (P<0.001). Erythrocyte catalase enzyme activity was negatively correlated with serum tHcy and TBARS while serum tHcy and TBARS were in positive correlation. Furthermore, the unbalance between pro-oxidants and antioxidants seems to be more aggravated in patients with Q wave AMI compared to patients with non-Q wave AMI.ConclusionOur results suggest the involvement of hyperhomocysteinaemia in the drop of erythrocyte catalase activity related to myocardial ischemia reperfusion. Hyperhomocysteinaemia may increase the myocardial wall dysfunction under ischemia reperfusion by excessive production of reactive oxygen species which is made evident by increased lipid peroxidation.Virtual slidesThe virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1623509866881834

Hsp70-2 gene polymorphism: susceptibility implication in Tunisian patients with coronary artery disease

AbstractCoronary artery disease (CAD) is a multifactorial disease where genetic and environmental factors interact in complex ways to cause the disease. Heat shock protein genes are involved in the progress of CAD. This implies that genetic variants of Hsp70–2 genes might contribute to the development of the CAD.Aim of studyThe aim of this study was to characterize statistical correlation of linkage between lipid profiles, polymorphism PstI site of Hsp70–2 gene and CAD.Patients and methodsThis study was carried out on Tunisian patients with CAD recruited from Hospital of Fattouma Bourguiba of Monastir-Tunisia. Polymerase chain reaction and restriction enzymes were used to determine the genotypic distributions in 252 unrelated patients and 151 healthy control subjects. Further, ApoA-I and ApoB as well as the serum total of cholesterol, HDL, triglyceride, and hs-CRP levels were measured.ResultsWe showed a decreased level of ApoA-I, whereas the levels of each of ApoB and hs-CRP were increased in patients with CAD compared with control group. In addition our studies of a polymorphic PstI site of Hsp70-2 gene at position 1267 of the Hsp70–2 gene have revealed that the allelic frequency of P2 was significantly more frequent in CAD patients than controls group (p=0.007, OR=1.495). The genotypic distribution showed a high incidence of P2/P2 genotype in CAD patients (0.190) compared to healthy control (0.009) with reach significant difference (p=0.006). The P2 carriers showed a significantly increased of Total-Cholesterol (CT) and C-reactive protein (hs-CRP) levels in CAD patients (p=0.008 and p=0.018, respectively).ConclusionThe high incidence of P2-Hsp70-2 genotype in CAD patients and the significantly association of P2/P2 genotype with elevated Total Cholesterol and hs-CRP levels, supported that P2–Hsp70–2 genotype has susceptibility implication in CAD and could increased the risk of CAD in Tunisian population.Virtual slidesThe virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1118340895703689

Polymorphisms in Tunisian patients with N-acetylgalactosamine-6-sulfate sulfatase gene deficiency: Implication in Morquio A disease

AbstractMucopolysaccharidosis type IVA or Morquio A syndrome is characterized by the lack of N-acetylgalactosamine-6-sulfate-sulfatase and the accumulation of keratan sulfate and chondroitin-6-sulfate in the lysosomes. At least, 148 mutations and 16 polymorphisms were identified in the GALNS gene.The aim of this study was the screening of polymorphisms within 7 patients recruited from many regions of Tunisia in order to determine the haplotypes and their association with the mutations previously reported.Patients and methodsWe have used the PCR sequencing to analyse the different haplotypes and to identify the polymorphisms within 7 affected MPS IVA patients.ResultsNine GALNS polymorphisms were detected in the 7 studied patients. Five of these polymorphisms are within the GALNS gene exons. Six polymorphisms have been previously described and used for linkage analysis in MPS IVA patients and determination of haplotypes. We have identified two novel heterozygous polymorphisms in intron 13 and intron 3ConclusionPolymorphisms may be useful for carrier detection and prenatal diagnosis in informative families whose specific mutations have not been identified. The determination of haplotypes can also determine the origin of some mutations in a population.

Paramètres du stress oxydant dans le diabète de type 2

Resume Introduction. – Des etudes recentes ont montre l’intervention des radicaux libres dans la genese des complications chroniques du diabete sucre. Il est admis que les LDL oxydees sont impliquees dans l’induction de l’atherosclerose. But. – Notre travail vise a mettre en evidence la variation des parametres metaboliques, le statut anti-oxydant et oxydant chez des diabetiques non insulinodependants (DNID). Methodes. – Cette etude a porte sur 39 DNID compares a 41 sujets temoins. La glycemie, l’hemoglobine glyquee (HbA1c), l’uree, la creatinine, l’acide urique, les triglycerides (TG), le cholesterol total (Chol-T), le HDL-cholesterol (HDL-chol), le LDL-cholesterol (LDL-chol), l’apolipoproteine A1 (Apo A1), l’apolipoproteine B (Apo B), le statut anti-oxydant total (Sat), les substances reagissant avec l’acide thiobarbiturique liees aux LDL (LDL-TBARS), l’ α-tocopherol, le cuivre et le zinc plasmatiques ont ete mesures ainsi que l’activite enzymatique de la superoxyde dismutase (Sod) et de la gluthation peroxydase (GPX). Resultats. – Dans la population diabetique etudiee par rapport aux temoins, l’activite de la GPX erythrocytaire et la concentration en uree plasmatique etaient inchangees, le statut anti-oxydant total (Sat), l’activite de Sod erythrocytaire, l’α-tocopherol, le zinc etaient significativement diminues. La concentration des LDL-TBARS etait augmentee. Conclusion. – La diminution des parametres Sat, Sod et l’augmentation des LDL-TBARS semblent constituer un signe d’alarme des complications graves qui apparaitront a moyen et long terme chez les DNID.

Founder effect confirmation of c.241A>G mutation in the L2HGDH gene and characterization of oxidative stress parameters in six Tunisian families with L-2-hydroxyglutaric aciduria

L-2-hydroxyglutaric aciduria (L2HGA) is an autosomal recessive neurometabolic disorder characterized essentially by the presence of elevated levels of L-2-hydroxyglutaric acid (LGA) in plasma, cerebrospinal fluid and urine. L2HGA is caused by a deficiency in the L2-Hydroxyglutaric dehydrogenase (L2HGDH) enzyme involved in the oxidation of LGA to the alpha 2-ketoglutarate. LGA has been proposed as an endo- and exogenous cytotoxic organic acid that induces free radical formation and generation of reactive oxygen species (ROS). In this report, we analyzed 14 L2HGA patients belonging to six unrelated consanguineous families the south of Tunisia. The patients were diagnosed with L2HGA disease confirmed on the presence of high level of LGA in urine. We analyzed the L2HGDH gene in all probands and identified the same c.241A>G homozygous mutation, which was previously reported in Tunisia. We also used intragenic single nucleotide length polymorphisms (SNPs) and two extragenic microsatellites flanking the L2HGDH gene to confirm the founder effect of c.241A>G mutation in the 14 studied cases. In addition, we carried out the measurement of the oxidative stress parameters in the plasma of L2HGA patients which revealed a significant increase in the malondialdehyde levels (MDA), a biomarker of lipid peroxydation, and the reduced glutathione (GSH). A diminution of the antioxidant enzyme activities including superoxide dismutase (SOD), glutathione peroxidase (GPx), was also observed.

Mucopolysaccharidosis IVA within Tunisian patients: Confirmation of the two novel GALNS gene mutations.

UNLABELLED Mucopolysaccharidosis type IVA or Morquio A disease is an autosomal recessive disease resulting from a deficiency of the lysosomal enzyme N-acetylgalactosamine-6-sulfate-sulfatase, which hydrolyses N-acetylgalactosamine-6-sulfate and galactose-6-sulfate in glycosaminoglycans. Phenotypes in Morquio A disease vary from the classical form with severe bone dysplasia, heart valve involvement, corneal opacity, short trunk dwarfism and a life span of 20 to 30 years, to attenuated forms with normal life span, mild bone involvement and mild visceral organ involvement. Unlike the other forms of mucopolysaccharidoses, Morquio A disease is characterized by normal intelligence. AIM OF THE STUDY The aims of this study were to determine if the novel GALNS anomalies IVS1+1G-A and G66R identified in Tunisia are mutations or polymorphisms. PATIENTS AND METHODS This study was carried out on six Morquio A patients recruited from many regions of Tunisia. We have used SCCP, sequencing and enzymatic digestion. RESULTS IVS1+1G-A and G66R were two deleterious mutations and not polymorphisms. CONCLUSION Screening of mutations and polymorphisms in GALNS gene provide useful information on genotype/phenotype correlations. It should also facilitate more accurate genetic counselling of newly diagnosed cases and their family members.