[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.

A novel 22bp deletion in a Tunisian phenylketonuria family.

Phenylketonuria (PKU) is an autosomal recessive metabolic disorder caused by a deficiency of phenylalanine hydroxylase. To date, more than 530 mutations in the PAH gene have been reported. In Tunisia, this disease seems to be the result of point mutations, few studies have been published about molecular defects of PKU in our country. In this study, we report a novel deletion in exon 6 of two brothers in a Tunisian family after DHPLC analysis and sequencing of the exon 6 of the PAH gene.

[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.

[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.

[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.

Clinical and mutational investigations of tyrosinemia type II in Northern Tunisia: identification and structural characterization of two novel TAT mutations.

Tyrosinemia type II or Richner-Hanhart Syndrome (RHS) is an autosomal recessive disorder characterized by keratitis, palmoplantar keratosis, mental retardation, and elevated blood tyrosine levels. The disease is due to a deficiency of hepatic cytosolic tyrosine aminotransferase (TATc), an enzyme involved in the tyrosine catabolic pathway. Because of the high rate of consanguinity this disorder seems to be relatively common among the Arab and Mediterranean populations. RHS is characterized by inter and intrafamilial phenotypic variability. A large spectrum of mutations within TATc gene has been shown to be responsible for RHS. In the present study, we report the clinical features and the molecular investigation of RHS in three unrelated consanguineous Tunisian families including 7 patients with confirmed biochemical diagnosis of tyrosinemia type II. Mutation analyses were performed and two novel missense mutations were identified (C151Y) and (L273P) within exon 5 and exon 8, respectively. The 3D-structural characterization of these mutations provides evidence of defective folding of the mutant proteins, and likely alteration of the enzymatic activity. Phenotype variability was observed even among individuals sharing the same pathogenic mutation.

[Gaucher's disease in Tunisia (multicenter study)]. / La maladie de Gaucher en Tunisie (étude multicentrique).

UNLABELLED: Gaucher's disease is one of the rare lysosomial disease that could receive substitutive enzymatic treatment which may improve considerably the prognosis of certain forms. The purpose of this work is to study the epidemiology of the disease in Tunisia, to highlight the diagnostic and therapeutic difficulties and also to precise our subsequent needs for substitutive medication. PATIENTS AND METHODS: We have conducted a retrospective survey of the hospital wards that were susceptible to take care of patients having Gaucher's disease. These wards are the paediatric, neonatology, internal medicine, haematology, neurology and cardiology wards. RESULTS: In this study we have observed 27 cases of Gaucher's disease over a period of 18 years (1983-2001). The age at onset ranges from birth to 73 years of age, with an average age of 14.5 years. According to the age at onset and the clinical presentation, we classify our patients into: 20 cases of type 1 (74%), three cases of type 2 (12%), and three cases of type 3 (12%), and one case of unspecified type.Gaucher's disease type 1: The age at onset ranged from 10 months to 73 years with an average of 19 years. The main clinical signs that we have observed were splenomegaly, hepatomegaly, pallor, haemorrhagic appearance and also osteoporosis and bone pain observed in 40% of the cases. The diagnosis was based on histology showing the Gaucher's cells in various tissues while the diagnosis obtained by the dosage of glucocerebrosidase took place only in 50% of the cases. The treatment has always been symptomatic (analgesics, transfusion). A splenectomy was performed in 47% of the cases and none of the patients received a specific treatment. The follow-up period ranged from 1 month to 18 years with an average follow-up of 4 years. Among the 12 patients having a follow-up of at least 1 year, we have noticed an improvement after splenectomy in three cases, a stability in three cases and two worsening cases dealing mainly with bone problems. One patient aged 73 died from respiratory problem and three were lost to follow-up. Gaucher's disease type 2: We have observed three cases of Gaucher's disease type 2 diagnosed at 1 day, 45 days and 3 months of age. The visceral manifestations were serious and the neurological features included seizures, hypertony, ocular-nerve palsies and psychometric decline. The three patients died. Gaucher's disease type 3: Three patients were probably suffering from Gaucher's disease type 3 with visceral manifestations observed at the ages of 9 months, 1 year and 3 years, and also neurological signs observed at respective ages of 2.5 and 3 years. Two patients died and the remaining one was lost to follow-up. CONCLUSION: Gaucher's disease is not exceptional in Tunisia. Type 1 is by far the most common one. We have noticed some insufficiency in the diagnosis as the glucocerebrosidase enzymatic dosage was performed only in 50% of the cases as well as therapeutic insufficiency with no prescription of the specific treatment.

[Neurologic Behçet disease]. / Neurobehçet.

BACKGROUND: Behçet's disease is very occasionally revealed by neurological abnormalities. This report describes such a case. CASE REPORT: A 13 year-old girl was admitted because of status epilepticus and fever. Clinical examination showed horizontal nystagmus, cerebellar syndrome, right hemiplegia, ophthalmoplegia and meningitis. Her CSF contained 80 lymphocytes/mm3, 0.75 milligram proteins and 0.5 milligram glucose. CT scan showed a hypodense area in the internal capsule. Two similar episodes occurred 4 and 6 months later, but all attempts at determining the etiology were negative. A diagnosis of neurological Behçet's disease was considered 10 months after the first episode when the patient developed oral ulcers followed by pseudofolliculitis of the scalp. The disease recurred several times despite treatment with prednisone, colchicine and antiaggregant drugs. CONCLUSION: Recurrent aseptic meningitis is a classic manifestation of neurological Behçet's disease. It usually appears 2 months to 27 years after the first extraneurological signs and not, as in this case, several months before.