Clinical and genetic characterization of Bardet-Biedl syndrome in Tunisia: defining a strategy for molecular diagnosis.

Bardet-Biedl syndrome (BBS, OMIM 209900) is a rare genetic disorder characterized by obesity, retinitis pigmentosa, post axial polydactyly, cognitive impairment, renal anomalies and hypogonadism. The aim of this study is to provide a comprehensive clinical and molecular analysis of a cohort of 11 Tunisian BBS consanguineous families in order to give insight into clinical and genetic spectrum and the genotype-phenotype correlations. Molecular analysis using combined sequence capture and high-throughput sequencing of 30 ciliopathies genes revealed 11 mutations in 11 studied families. Five mutations were novel and six were previously described. Novel mutations included c.1110G>A and c.39delA (p.G13fs*41) in BBS1, c.115+5G>A in BBS2, c.1272+1G>A in BBS6, c.1181_1182insGCATTTATACC in BBS10 (p.S396Lfs*6). Described mutations included c.436C>T (p.R146*) and c.1473+4A>G in BBS1, c.565C> (p.R189*) in BBS2, deletion of exons 4-6 in BBS4, c.149T>G (p.L50R) in BBS5, and c.459+1G>A in BBS8; most frequent mutations were described in BBS1 (4/11, 37%) and BBS2 (2/11, 18%) genes. No phenotype-genotype correlation was evidenced. This data expands the mutations profile of BBS genes in Tunisia and suggests a divergence of the genetic spectrum comparing Tunisian and other populations.

[Rubella seroprevalence in Tunisian childbearing women two years after vaccination program introduction]. / Séroprévalence de la rubéole chez la femme en âge de procréer deux ans après l'introduction de la vaccination en Tunisie.

UNLABELLED: Acquiring rubella during the first 20 weeks of pregnancy can lead to teratogenic effects. AIM: The aim of the study was to investigate the impact of rubella vaccination strategy two years after its introduction in Tunisia in 2005. METHODS: This study was conducted over two periods, 2000 and 2007-2008. A total of 15,776 childbearing women were enrolled in the sample. Serological studies were performed by using the ELISA method. RESULTS: Overall, rubella infection seroprevalence did not increase between 2000 and 2007-2008. Nevertheless, a significant increase in seroprevalence, from 78.2% in 2000 to 92% in 2007-2008 (P=0.006), was especially noted in the age group under 20 years. Seroprevalence did also statistically increase with parity in 2007-2008 from 77.4% in women without any parity to 89.8% in women with over three parities (P=0.01). CONCLUSIONS: Results improvements seem most likely due to mass vaccination campaign for girls aged from 13 to 18 years in 2005, and also routinely post-partum vaccination of seronegative pregnant women or women ignoring their rubella status. In the coming years, systematic selective immunization of 12-year-old schoolgirls who are not yet entering their prime childbearing years will achieve female population sufficient immunity.

[Nonketotic hyperglycemia-induced hemiballism]. / Hémiballisme secondaire à une hyperglycémie sans cétose.

Nonketotic hyperglycemia-induced hemichorea or hemiballism is a well-recognized entity that is rarely encountered. Particular computed tomography and magnetic resonance imaging findings have been described. The pathophysiological mechanism of this disease remains uncertain. We report here on two female patients that presented with hemiballism secondary to nonketotic hyperglycemia and underwent brain computed tomography and magnetic resonance imaging.

Only two mutations detected in 15 Tunisian patients with 11ß-hydroxylase deficiency: the p.Q356X and the novel p.G379V.

Steroid 11ß-hydroxylase deficiency is the second most common cause of congenital adrenal hyperplasia, resulting in virilization, glucocorticoid deficiency and hypertension. The 11ß-hydroxylase enzyme is encoded by the CYP11B1 gene and mutations in this gene are responsible for this disease. The aim of this study was to characterize mutations in the CYP11B1 gene and to determine their frequencies in a cohort of Tunisian patients. The molecular genetic analysis was performed by direct nucleotide sequencing of the CYP11B1 gene in 15 unrelated Tunisian patients suffering from classical 11ß-hydroxylase deficiency. Only two mutations were detected in homozygous state in the CYP11B1 gene of all patients, the p.Q356X in exon 6 (26.6%) and the novel p.G379V in exon 7 with large prevalence (73.3%). This is the first report of screening for mutations of CYP11B1 gene in the Tunisian population and even in the Arab population.

A novel UBE3A truncating mutation in large Tunisian Angelman syndrome pedigree.

We identified in a large Tunisian pedigree a novel UBE3A frameshift mutation in exon 16 coding region, and we expect that the resulting UBE3A truncated protein in our patients is non-functional since the mutation implies the catalytic region of the enzyme. The family includes 14 affected patients born from four sisters. This mutation was found in all surviving affected individuals and their mothers pointing out the importance of genetic counseling possibility in Angelman syndrome (AS). All patients had severe mental retardation with epilepsy and microcephaly. Minor clinical expression variation was observed among the investigated patients. The severity of clinical expression is related to the detected molecular variation: deletion of 15 bp and insertion of 7 bp. These results are concordant with the gene expression observed in previously reported individuals with AS and truncated UBE3A protein.

SQSTM1 mutation: Description of the first Tunisian case and literature review.

BACKGROUND: Mutations in SQSTM1 gene have been recently identified as a rare cause of progressive childhood neurodegenerative disorder. So far, only 25 patients from 10 unrelated families were reported. METHODS AND RESULTS: We report on the first Tunisian case of an 11-year-old girl with cerebellar ataxia, chorea and ophthalmoparesis. Brain MRI was normal. Whole-exome sequencing revealed a homozygous mutation c.823_824del(p.Ser275Phefs*17) in SQSTM1 gene (GenBank: NM_003900.4). CONCLUSION: By pooling our data to the data of literature, we delineated the phenotypic spectrum and stressed on genetic heterogeneity of this rare neurodegenerative disease.

Comparison of hepatitis A seroprevalence in blood donors in South Tunisia between 2000 and 2007.

The aim of the study was to assess hepatitis A virus (HAV) seroprevalence in blood donors from South Tunisia in two periods 2000 and 2007. Serum samples collected from 376 blood donors in each period aged 18 to 30 years from different regions of South Tunisia were analysed for anti-HAV IgG. The global seroprevalence of HAV infection was 85.9% in 2007 as compared with 94.9% in 2000. The seroprevalence in the 18-20 years age group was 91.9% in 2000 vs 80.6% in 2007, and increased to 99% in 2000 and 92% in 2007 in the subjects over 26. Taking account of geographic area, the HAV seroprevalence in Sfax city decreased from 88.9% in 2000 to 62.7% in 2007 (p < 0.001), but it is still approximatively the same in rural areas (98.4% and 96%) and in the governorates of South Tunisia (97.6% and 99.2%). In conclusion, the number of adults in the city of Sfax which are not immunized against HAV is increasing. Thus, adolescents and young adults are at risk to develop symptomatic and potentially severe hepatitis A.

[Genetic analysis of Turner syndrome: 89 cases in Tunisia]. / Analyse génétique du syndrome de Turner : étude tunisienne de 89 cas.

Turner's syndrome (TS) affects about 1/2500 female infants born alive. The syndrome results from total or partial absence of one of the two X chromosomes normally present in females. We report the results of a retrospective analysis of 89 cases of TS observed during a six-year period (2000-2005). The patients' age ranged from two days to 51 years at the time of this analysis. Most patients were adults (48%). The aim of this study is to ascertain the principal clinical features leading to a request for a karyotype, searching for a possible relationship between chromosomal anomalies and clinical expression of TS. Pediatric patients were referred for statural retardation or dysmorphic features, while reproduction anomalies were the main indication for karyotyping in patients aged over 20 years. Mosaicism was prevalent (47%), whereas the homogeneous karyotype 45,X was found in only 32% of the patients; structural anomalies were found in 21%. Regarding the advanced age of our patients, we established a relationship between chromosome anomalies and the clinical expression of TS, based on an analysis of stature and reproduction disorders. Short stature and primary amenorrhea were correlated with total deletion of one chromosome X or imbalanced gene dosage due to structural X anomalies. Whereas cases of infertility, recurrent miscarriages and secondary amenorrhea were associated with a mosaic karyotype pattern (45,X/46,XX or 45,X/46,XX/47,XXX ...), with a slight mosaicism in most cases. Thus, chromosome investigations should be performed in cases of reproduction failure even for women with normal stature.

[Diagnostic strategy of mucopolysaccharidosis type I in Tunisia]. / La mucopolysaccharidose de type I: stratégie diagnostique en Tunisie.

A Tunisian patient affected by mucopolysaccharidosis (MPS) was investigated for a biological analysis (quantitative and qualitative glycosaminoglycans (GAG) screening). We have also done an enzymatic determination of alpha-L-iduronidase activity (IDUA). The most common mutation (p.Gln 70 X, p.Trp 402X and p.Pro 533 Arg) were researched by an enzymatic restriction and sequencing of the IDUA gene. Enzymatic and urinary diagnostics suggested a MPS I phenotype. The patient investigated had the mutation p.Pro 533 Arg in the homozygous status, whereas his parents were heterozygous for this mutation.

[Clinical, biologic and molecular characteristics of two Tunisian MPS IV A patients]. / Etude de la maladie de Morquio A dans une famille tunisienne présentant deux enfants atteints.

Mucopolysaccharidosis type IV A (MPS IV A) is an autosomal recessive disorder resulting from the deficient activity of the lysosomal enzyme, N-acetylgalactosamine-6-sulfate sulfatase (GALNS) and the progressive lysosomal accumulation of keratane sulfate. Clinically, the MPS IV A differs from the other MPS by the localisation of the keratane sulfate in skelet and in eyes associated to the conservation of a normal intelligence. To date, the characterization and purification of the GALNS gene made a research for pathogenic mutations in patients with MPS IV A easier. These mutations are responsible of severe, intermediate or mild phenotype. The aim for this work was the research of clinical, biologic and molecular characteristics of two Tunisian MPS IV A patients who were offsprings of consanguineous mating. Enzymatic and urinary diagnostics suggested a MPS IV A phenotype. A novel homozygous mutation IVS1+1G-A was identified by direct sequencing in the GALNS gene of the two patients. Identification of GALNS mutations provide genotype/phenotype correlations and permit the precision of anomalies responsible of Morquio A phenotype in concerned families.

[Mucopolysaccharidosis type I: identification of alpha-L-iduronidase mutations in Tunisian families]. / La mucopolysaccharidose de type I: identification des mutations du gène alpha-L-iduronidase dans des familles tunisiennes.

UNLABELLED: Mucopolysaccharidosis type I (MPS I) is a lysosomal disease due to mutations in the gene encoding alpha-l-iduronidase (IDUA) leading to variable clinical phenotypes with progressive severe organomegaly, bone and neurological involvement in the most severe forms. The aim of our study was to propose in Tunisia a strategy of molecular and prenatal diagnosis of the MPS I. POPULATION AND METHODS: Our study was carried out on 8 MPS I patients recruited from different Tunisian regions and issued from 5 unrelated families. All the patients were offspring of consanguineous marriages. RESULTS: The clinical and biological study led to diagnose 5 Hurler patients and 3 Hurler-Scheie patients. Three IDUA mutations were identified by molecular analysis within 6 different families: a novel mutation p.F602X and 2 already described mutations p.P533R and p.R628X. DISCUSSION: MPS I is a heterogeneous disease characterized by variability of the phenotypes. The missense mutation p.P533R associated with the intermediate phenotype was the most frequent in the Tunisian but also in the Moroccan population. In Tunisia, the incidence of p.P533R mutation seems to be associated with the high frequency of consanguineous marriages. CONCLUSION: The identification of known MPS I mutations (p.P533R and p.R628X) and of the novel mutation p.F602X permits reliable genetic counselling of at-risk relatives and molecular prenatal diagnosis.

[Devic's neuromyelitis optica in children: a case report and review of the literature]. / Neuromyélite optique de Devic chez l'enfant: à propos de 1 cas, avec revue de la littérature.

UNLABELLED: Devic neuromyelitis optica (NMO) or Devic's syndrome is an uncommon clinical syndrome associating unilateral or bilateral optic neuritis and transverse myelitis. Usually reported in adults, childhood cases constitute a distinctive clinical entity. CASE REPORT: We report a case of NMO occurring in a 9-year-old girl, admitted for paraplegia, sphincter troubles as acute installation bladder retention and of a sudden decline of the visual acuity. Magnetic resonance imaging (MRI) revealed abnormalities of spinal cord signal with hypo intensity in T1-weighted images and hyper intensity in T2-weighted images along the spinal cord. However, the cerebral region was normal. Visual evoked potentials were consistent with retrobulbar optic neuropathy. Our patient received corticosteroids (methyl prednisolone) during 5 days followed by oral prednisone. At week three, an immunosuppressant (azathioprine) was added. Clinical outcome was favourable with disappearance of sphincter troubles, a correction of the visual acuity and a progressive disappearance of motor troubles. CONCLUSION: Pediatric Devic's NMO is rare. It is a different clinical entity with an excellent visual and neurological prognosis. Review of the literature shows that recurrence is rare in children and seems to be without long-term sequelae with corticosteroids and immunosuppressant therapy.

[Parathyromatosis: An uncommon cause of recurrent hyperparathyroidism]. / Parathyromatose : une cause rare d'hyperparathyroïdie récidivante.

INTRODUCTION: Parathyromatosis is a rare cause of recurrent hyperparathyroidism. It results from hyperfunctioning parathyroid tissue scattered throughout the thyroid bed region. CASE REPORT: A 51-year-old man with a history of parathyroidectomy, presented 18 years later with recurrent primary hyperparathyroidism. Surgical exploration identified a single parathyroid gland. The act was completed by a central compartment dissection and ipsilateral lobectomy. The patient was free of recurrence after a one-year follow-up. CONCLUSION: Parathyromatosis a rare cause of recurrent hyperparathyroidism. Its management is challenging. Extensive surgery is required with clearance of the central neck compartment and homolateral lobectomy. Medical therapy could be used to decrease parathormone level in recurrent parathyromatosis.

Prenatal diagnosis and molecular characterization of an interstitial 1q24.2q25.2 deletion.

We report on the observation of an interstitial deletion of the long arm of chromosome 1 diagnosed prenatally in a 28 weeks gestation fetus by standard karyotype. Amniocentesis was performed because of an increased Down syndrome maternal serum screening and ultrasonographic abnormalities. Fetus autopsy showed an intrauterine growth retardation, dysmorphic features and limbs abnormalities. Using fluorescent in situ hybridization technique (FISH), we characterized the deletion boundaries corresponding to the bacterial artificial chromosomes (BAC) RP11-193J5 and RP11-162L13. Molecular studies identified the deletion of paternal origin. Therefore the karyotype was interpreted as 46,XY,del(1)(q24.2q25.2). This is the smallest deletion of the long arm of chromosome 1 reported prenatally and characterized at the molecular level. Its phenotype is compared to other similar cases described in the literature.

Molecular cytogenetic analysis of five 2q37 deletions: refining the brachydactyly candidate region.

Deletions of the 2q37 region are associated with a recognizable pattern of MCA/MR so-called the AHO-like syndrome. Brachydactyly is a variable but characteristic feature of this clinical entity. Here we report on five cases of cytogenetically visible de novo deletions of this 2q37 chromosome region. Using FISH, we characterized at the molecular level the breakpoints of these deletions using a set of 15 BACs, PACs and YACs. In four patients, terminal deletions of variable size ranged between 6.2 and 10 Mb. The fifth patient had an interstitial deletion with an AHO-like phenotype including brachydactyly. These findings when compared to previous observations allowed us to narrow down the brachydactyly critical region between BACs RP11-585E12 and RP11-351E10. It contains HDAC4 and STK25 candidate genes loci.

Burkitt lymphoma in a child with Bloom syndrome.

BACKGROUND: Bloom syndrome is a rare disease characterized by chromosomal instability and increased risk of developing lymphoma. OBSERVATION: We report on a case of Bloom syndrome in a 5-year-old boy with Burkitt lymphoma. The diagnosis was suspected by growth retardation, repeated respiratory infections, facial telangiectasia, and a low immunoglobulin level, then confirmed cytogenetically by sister chromatid exchanges. Chemotherapy was poorly tolerated, which required reducing the doses. Unfortunately, it was not sufficient to control the neoplasm and the patient died 14 months after diagnosis. CONCLUSIONS: Cancers in Bloom syndrome are a challenge since the potentially life-threatening side effects of the chemotherapy may require modifications in standard treatment such as dose reduction, which can compromise the tumor prognosis.

[Retinal detachment after Excimer laser (myopic LASIK or PRK). A retrospective multicentric study: 15 cases]. / Décollement de rétine post laser Excimer (Lasik/PKR myopique). Etude multicentrique rétrospective (15 cas).

INTRODUCTION: Refractive surgery by LASIK or photorefractive keratectomy (PRK) generaly aims at a myopic population that has a high probability of developing rhegmatogenous retinal detachment (RD). The authors report a multicenter study with 15 cases of RD appearing after refractive surgery by Excimer laser and discuss the role played by the techniques used. MATERIAL AND METHODS: Five centers fitted with nine Excimer laser devices took part in this study. Of 22,700 eyes undergoing refractive myopic surgery during the period 1994-2002, 15 eyes developed rhegmatogenous RD. The average age of the patients with RD was 37 years. The average myopia was 13.5 D. RD occurred a mean of 20 months after refractive laser. RESULTS: Fifteen eyes of 13 patients developed a rhegmatogenous RD, two of which were bilateral. Eight of these cases had LASIK surgery and six had photorefractive keratectomy; one of the latter patients was retreated with LASIK because of substantial regression after PRK. RD was total or subtotal in five eyes, partial superior with a temporal tear in six eyes, and nasal in three eyes. One case with inferior RD, two cases with giant retinal tear and one case with posterior tear were also repaired. Fourteen eyes were suitable for operation. The retina was reattached in 12 cases. Mean postoperative visual acuity was 7/10. DISCUSSION: The occurrence of rhegmatogenous RD in the myopic population is estimated at 2.2%. It is estimated at 0.1% in the emmetropic population. The Excimer laser, through its thermic effects, shock wave, traumatism undergone by the suction ring at the time of LASIK surgery, could increase this risk in myopic patients. A review of the literature cast doubt on the cause and effect hypothesis. Personal and multicenter studies (including ours) show that the frequency rate of rhegmatogenous RD after Excimer laser is equivalent and even lower than that estimated with an emmetropic population. The low percentage of RD after Excimer surgery found in the literature as well as in our study (<0.1%) may be explained by patient selection, the systematic monitoring of the peripheral fundus, and the prophylactic treatment of degenerative lesions by photocoagulation. In RD surgery, the cornea must be manipulated carefully, a case of flap dehiscence has been reported in the literature. CONCLUSION: Refractive surgery by LASIK or PRK for severe myopia increases the risk of RD. Systematically monitoring the peripheral fundus and preventive photocoagulation have mitigated its occurrence, and the risk incurred in the myopic population has fallen to the emmetropic population's rate. Nevertheless, candidates for LASIK or PRK surgery must be informed because severe myopia constitutes a non-negligible risk factor.

A novel locus for Usher syndrome type II, USH2B, maps to chromosome 3 at p23-24.2.

Usher type II syndrome is defined by the association of retinitis pigmentosa, appearing in the late second to early third decade of life, with congenital moderate to severe non-progressive hearing loss. This double sensory impairment is not accompanied by vestibular dysfunction. To date, only one Usher type II locus, USH2A, at chromosome band 1q41, has been defined. Here, we demonstrate by linkage analysis, that the gene responsible for Usher type II syndrome in a Tunisian consanguineous family maps to chromosome 3 at position p23-24.2, thus providing definitive evidence for the genetic heterogeneity of the syndrome. A maximum lod score of 4.3 was obtained with the polymorphic microsatellite markers corresponding to loci D3S1578, D3S3647 and D3S3658. This maps the gene underlying USH2B to a chromosomal region which overlaps the interval defined for the non-syndromic sensorineural recessive deafness DFNB6, raising the possibility that a single gene underlies both defects. However, the audiometric features in the patients affected by USH2B and DFNB6 are very different.

[Determination of anti-transglutaminase antibodies in the diagnosis of coeliac disease in children: results of a five year prospective study]. / Dosage des anticorps anti-transglutaminase dans le diagnostic de la maladie coeliaque de l'enfant: résultats d'une étude prospective sur cinq ans.

AIM: To evaluate the interest of IgA antibodies to tissue transglutaminase in the diagnosis of children coeliac disease compared with anti-endomysium and anti-gliadin antibodies. SUBJECTS AND METHODS: Seventy children with coeliac disease (mean age: 5 years and 8 months) and 99 disease controls (mean age: 4 years and 5 months). IgA anti-transglutaminase were tested by ELISA using a human recombinant tissue transglutaminase. IgA anti-endomysium were detected by indirect immunofluorescence on monkey oesophagus. RESULTS: The middle rate of IgA anti-transglutaminase was 101.06 units in patients and only 0.47 unit in controls. IgA anti-transglutaminase and IgA anti-endomysium were in agreement in 98.8% of cases; only two cases were discordant (+/- and -/+). Globally, the two markers had the same sensitivity (90%), specificity (98%), negative (93.2%) and positive (96.9%) predictive values. For anti-gliadin antibodies, the IgG were more sensitive (88.6%) and the IgA more specific (93.9%). CONCLUSION: IgA anti-tissue transglutaminase can be used instead of IgA anti-endomysium as a serological marker of screening and diagnosis of coeliac disease in children after 3 years.