[Molecular diagnosis of Gaucher disease in Tunisia]. / Diagnostic moléculaire de la maladie de Gaucher en Tunisie.

Gaucher disease is a lysosomal storage disorder caused by a deficiency of the enzyme acid ß-glucosidase. In order to determine the mutation spectrum in Tunisia, we performed recurrent mutation screening in 30 Tunisian patients with Gaucher disease. Screening of recurrent mutation by PCR/RFLP and direct sequencing had shown that N370S was the most frequent mutation (22/50 mutant alleles, 44%), followed by L444P mutation, which is found in 16% (8/50 mutant alleles). The recombinant allele (RecNciI) represented 14%. Our findings revealed that the genotype N370S/RecNciI was mosst frequent in patients with childhood onset and it was associated with severe visceral involvement. The screening of these three mutations provided a simple tool for molecular diagnosis of Gaucher disease in Tunisian patients and allowed also genetic counselling for their family members.

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.

[Rosai-Dorfman disease: therapeutic issues in 2 cases]. / La maladie de Rosai - Dorfman : enjeux thérapeutiques à propos de 2 observations.

Rosai-Dorfman disease (RDD) is a benign lymphoproliferative disorder characterized by cervical lymph node enlargement with a consistent risk of airway compression and esthetic damage. Extranodal localizations are also described. There is no therapeutic consensus for pediatric forms of RDD. Through 2 pediatric cases with nodal involvement in 1 patient and a sinonasal and soft tissue localization in the other, we focus on the management problems of both nodal and extranodal RDD.

Molecular characterization of MPS IIIA, MPS IIIB and MPS IIIC in Tunisian patients.

Sanfilippo syndrome (mucopolysaccharidosis type III, MPS III) is a progressive disorder in which patients are characterized by severe central nervous system degeneration together with mild somatic disease. MPS III results from a deficiency in one of the four enzymes involved in the heparan sulfate degradation, with sulfamidase (SGSH), α-N-acetylglucosaminidase (NAGLU), acetyl-coenzyme A: α-glucosaminide N-acetyltransferase (HGSNAT), and N-acetylglucosamine-6-sulfatase (GNS) being deficient respectively in MPS IIIA, MPS IIIB, MPS IIIC and MPS IIID. Mutation screening using PCR reaction/sequencing analysis on genomic DNA fragments was performed in seven Tunisian index cases with MPS IIIA, three with MPS IIIB and two with MPS IIIC. QMPSF (Quantitative Multiplex PCR of Short fluorescent Fragments) analysis was developed for the detection of genomic deletions and duplications in the SGSH gene. These approaches allowed the identification of 11 mutations, 8 of them were novel including a mutation involving the start codon (p.Met1?), one small duplication (p.Leu11AlafsX22), one small deletion (p.Val361SerfsX52) and a large deletion of exon 1 to exon 5 in the SGSH gene, one missense mutation (p.Pro604Leu) and one nonsense mutation (p.Tyr558X) in the NAGLU gene and, finally, one missense mutation (p.Trp627Cys) and one nonsense mutation (p.Trp403X) in the HGSNAT gene.

Phenotypic continuum of type 2 Gaucher's disease: an intermediate phenotype between perinatal-lethal and classic type 2 Gaucher's disease.

The natural history and clinical presentation of the perinatal-lethal Gaucher's disease, a severe variant of acute type 2 Gaucher's disease, is quite different from classic type 2 Gaucher's disease. Rare reported patients had an overlapping phenotype between these two forms confirming that phenotyping may be difficult. Here we report three patients with an intermediate phenotype. The first two patients showed at birth cholestatic jaundice, hepatosplenomegaly and hematological involvement consistent with hemophagocytosis in one patient, the death occurred from a severe liver involvement in one and lung disease in the second in the absence of neurological symptoms. The third patient displayed ichthyosis and facial dysmorphism but with neurological degeneration course and survival consistent with classic type 2 Gaucher's disease.

[Congenital generalized lipodystrophy: a case report with neurological involvement]. / Lipodystrophie congénitale généralisée de type 1 avec atteinte neurologique.

Congenital generalized lipodystrophy (CGL) is a rare disorder characterized by near complete absence of adipose tissue from birth. At least 2 genes located in 9q34 (AGPAT2) and 11q13 (Seipin) are implicated in type 1 and 2, respectively, and result in insulin resistance. We report here a novel case of CGL type 1 resulting from a novel homozygote mutation in the AGPAT2 gene. The clinical picture included pseudoathletic muscular hypertrophy, hypertrophic cardiomyopathy, enlarged liver, hypermetabolism rate, and hyperinsulinemia in a 1-year-old child from Libya. Peripheral hypertonia and reflex excitability revealed signal abnormalities in white matter on magnetic resonance imagery, which has not been described previously in the literature.

Mucopolysaccharidoses type I and IVA: clinical features and consanguinity in Tunisia.

UNLABELLED: Mucopolysaccharidoses (MPS) are a group of lysosomal storage disorders caused by the deficiency of specific enzymes which leads to the lysosomal accumulation of glycosaminoglycanes. Mucopolysaccharidosis type I or Hurler disease is characterized by the deficiency of alpha-l-iduronidase enzyme. Mucopolysaccharidosis type IVA or Morquio A disease is due to the lack of N-acetylgalactosamine-6-sulfate-sulfatase. Theses deficiencies result in a progressive accumulation of the substrates: dermatan and heparan sulfates for Mucopolysaccharidosis type I and keratan sulfate for MPS type IVA. This process leads to progressive and chronic course for visceral attacks of the affected organs such as lungs and heart. In the Hurler disease, the nervous system is particularly affected while in Morquio a disease, a skeletal dysplasia and a normal intelligence are characteristic. AIM OF THE STUDY: This study was carried out on MPS type I and MPS type IVA unrelated families recruited from many regions of Tunisia in order to determine the relation between consanguinity and these types of disorders. PATIENTS AND METHODS: Clinical and molecular analyses confirmed the diagnosis for four MPS type I and five MPS type IVA studied families. RESULTS: First cousins unions characterize all families except one Hurler family and one Morquio A family where the consanguinity is third cousin degree. CONCLUSION: MPS type I and type IVA seems to be associated with consanguinity in Tunisia.

[Atypical presentation of Wegener disease in childhood]. / Présentation atypique de la maladie de Wegener de l'enfant.

The pediatric forms of Wegener granulomatosis (WG) are rare. The clinical picture and the profile have specificities compared to those of adults. We report a case of a girl aged of four years and a half who presented initially with a clinical picture of Henoch Schönlein purpura. Physical examination revealed additionally to purpura, scabby lesions on the buttocks. The histopathological examination of a skin biopsy disclosed histiocyte infiltration. There were no Ig A deposits on direct immunofluorescence study. One year later, the diagnosis of WG was suspected, when the patient developed a respiratory problem related to left pulmonary infarction. Screening for thromboembolic factors was positive for antiphosphilipid antibodies. Diagnosis of WG was confirmed by the histopathological study lung tissue and a significant titre of serum ANCA. Blood tests failed to provide evidence of renal involvement. Cyclophosphamide and prednisolone therapy was administrated. A relapse occurred one year later on the controlateral lung; but no biological marker of disease activity could be detected.

Glycogen storage disease type I in Tunisia: an epidemiological analysis.

OBJECTIVE: Analysis of epidemiological data concerning GSD I in Tunisia. SUBJECTS AND METHODS: All the cases diagnosed as GSD I between 1992 and 2005 in a paediatric department recruiting all the metabolic diseases referred from the North of Tunisia were reviewed. Individual data (sex, socioeconomic and educational background, geographic origins, insurance coverage) were collected and pedigrees were reconstituted. RESULTS: Twenty-two cases (9 boys and 13 girls from 20 homes) were identified. Fourteen belonged to 11 families originating from the North of Tunisia; ten of them are still alive. Both parents in 4 homes (21%) and one parent in 9 homes (47%) were illiterate. Most of the homes (60%) had a low income and 45% comprised at least 3 children. Only 7 homes (35%) had health insurance. Pedigrees indicated 44 infant deaths and at least 10 other cases fulfilling the clinical features of GSD I but not diagnosed. CONCLUSION: The paediatric prevalence of GSD I in the North of Tunisia can be estimated to 7.93 cases per one million inhabitants and its incidence to 1/100,000 births. However, it is likely to be more frequent because of underreporting or underdiagnosis leading to precocious deaths.

Phenotypic spectrum of fucosidosis in Tunisia.

Fucosidosis (OMIM 230000) is a rare autosomal recessive lysosomal disorder due to deficient α-L-fucosidase activity(EC 3.2.1.51), leading to the accumulation of fucose-containing glycolipids and glycoproteins in various tissues. This study contained the largest ever Tunisian survey of fucosidosis patients, diagnosed during the period 1987-2007. The clinical pictures and outcomes of these patients are compared with literature data. Ten patients (8 boys and 2 girls) from six unrelated families were diagnosed at a mean age of 29 ± 10.3 months. Six of the patients were diagnosed as having the more severe phenotype. The other four cases presented the low progressive phenotype. This distinction was determined by the presence or absence of angiokeratoma and age of death. For all of the patients in our survey, early motor development was more severely delayed than described in the literature. Six patients presented psychomotor decline during the second year of life. Clinical features consist of variable mental retardation (all patients), progressive spastic quadriplegia (6/10 cases), coarse facies (9/10 cases), growth retardation (7/9 cases), visceromegaly (3 cases), angiokeratoma corporis diffusum (4 cases), recurrent bronchopneumonias (all cases), seizures (4 cases) and variable degrees of dysostosis multiplex (all cases). Portal cavernoma, never described in the literature, was observed in one patient. The outcomes were severe in this survey, probably owing to restricted health care; death occurred in 6 of the 10 patients before age 10 years, following recurrent pulmonary infections and neurological deterioration. No intrafamilial variability was noted in the multiplex families. The clinical presentation and outcomes of some of these patients were consistent with the continuous clinical spectrum of severity in fucosidosis attested by most clinical studies.

Mutation spectrum of glycogen storage disease type Ia in Tunisia: implication for molecular diagnosis.

Glycogen storage disease type Ia (GSD Ia; OMIM 232200) is an autosomal recessive disorder of glycogen metabolism caused by a deficiency of the microsomal glucose-6-phosphatase (G6Pase). It is characterized by short stature, hepatomegaly, hypoglycaemia, hyperuricaemia, and lactic acidaemia. Various mutations have been reported in the G6Pase gene (G6PC). In order to determine the mutation spectrum in Tunisia, we performed mutation analysis in 22 Tunisian type I glycogen storage disease (GSD I) patients belonging to 18 unrelated families. All patients were clinically classified as GSD Ia. The R83C mutation was found to be the major cause of GSD Ia, accounting for 24 of 36 mutant alleles (66.6%), The R170Q mutation was the second most frequent mutation; it accounts for 10 of 36 mutant alleles (27.7%). The R83C and R170Q mutations could be rapidly detected by PCR/RFLP. Since the majority of Tunisian patients carried R83C and/or R170Q mutations, we propose direct screening of these mutations as a rapid, valuable and noninvasive tool for diagnosis of GSD Ia in Tunisian as well as in Northern African populations.

[Renal involvement in Fabry disease]. / Atteinte renale au cours de la maladie de Fabry.

BACKGROUND: Fabry disease is an X-linked recessive lysosomial storage disorder that is caused by deficient activity of alpha galactosidase A. Renal involvement occurs generally in hemizygous forms. AIM: We report one case of renal involvement in Fabry disease. CASE REPORT: A 47 year-old-man had focal and segmental glomerulosclerosis with moderate renal failure. As the patient presented history of acroparesthesias, hearing loss, left ventricular hypertrophy with arrhythmia and corneal deposits, hemizygous Fabry disease was suspected. This diagnosis was confirmed with low alpha galactosidase activity. After a follow up of 5 years, the renal function remains stable but the patient died by cardiac arrhythmia. CONCLUSION: Occurrence of a glomerulonephritis associated with an hypertrophic cardiopathy without hypertension should advocate Fabry disease.

[Mutation spectrum of Gaucher disease in Tunisia: high frequency of N370S/Rec NciI compound heterozygous]. / Spectre mutationnel de la maladie de Gaucher en Tunisie: forte fréquence des hétérozygotes composites N370S/Rec NciI.

Gaucher disease is the most common lysosomal storage disorder, it results from the inherited deficiency of the enzyme glucocerebrosidase, the accumulation of its substrate causes many clinical manifestations. Since the discovery of GBA gene, more than 200 different mutations have been identified, but only handful mutations are recurrent (N370S, L444P and c.84insG). In order to determine the mutation spectrum in Tunisia, we performed recurrent mutation screening in ten unrelated Tunisian children with Gaucher disease. Screening of recurrent mutation by PCR/RFLP and direct sequencing, has shown that N370S is the most frequent mutation (6/20 mutant alleles, 30%), followed by recombinant allele (RecNciI) which is found in five patients (5/20 mutant alleles, 25%), the L444P mutation represent 20% (4/20 mutant alleles). Our findings revealed that five among ten studied patients, were compound heterozygous N370S/RecNciI (50%). The screening of these mutations provides a simple tool for molecular diagnosis of Gaucher disease in Tunisian patients and allows also genetic counselling for their family members.