Stroke in the Middle-East and North Africa: A 2-year prospective observational study of intravenous thrombolysis treatment in the region. Results from the SITS-MENA Registry.

BACKGROUND AND METHODS: Intravenous thrombolysis for acute ischemic stroke in the Middle-East and North African (MENA) countries is still confined to the main urban and university hospitals. This was a prospective observational study to examine outcomes of intravenous thrombolysis-treated stroke patients in the MENA region compared to the non-MENA stroke cohort in the SITS International Registry. RESULTS: Of 32,160 patients with ischemic stroke registered using the SITS intravenous thrombolysis protocol between June 2014 and May 2016, 500 (1.6%) were recruited in MENA. Compared to non-MENA (all p < 0.001), median age in MENA was 55 versus 73 years, NIH Stroke Scale score 12 versus 9, onset-to-treatment time 138 versus 155 min and door-to-needle time 54 min versus 64 min. Hypertension was the most reported risk factor, but lower in MENA (51.7 vs. 69.7%). Diabetes was more frequent in MENA (28.5 vs. 20.8%) as well as smoking (20.8 vs. 15.9%). Hyperlipidemia was less observed in MENA (17.6 vs. 29.3%). Functional independence (mRS 0-2) at seven days or discharge was similar (53% vs. 52% in non-MENA), with mortality slightly lower in MENA (2.3% vs. 4.8%). SICH rates by SITS-MOST definition were low (<1.4%) in both groups. CONCLUSIONS: Intravenous thrombolysis patients in MENA were younger, had more severe strokes and more often diabetes. Although stroke severity was higher in MENA, short-term functional independency and mortality were not worse compared to non-MENA, which could partly be explained by younger age and shorter OTT in MENA. Decreasing the burden of stroke in this young population should be prioritized.

Exome sequencing: an efficient diagnostic tool for complex neurodegenerative disorders.

BACKGROUND AND PURPOSE: Autosomal recessive cerebellar ataxia (ARCA) comprises a large and heterogeneous group of neurodegenerative disorders. We studied three families diagnosed with ARCA. METHODS: To determine the gene lesions responsible for their disorders, we performed high-density single-nucleotide polymorphism genotyping and exome sequencing. RESULTS: We identified a new mutation in the SACS gene and a known mutation in SPG11. Notably, we also identified a homozygous variant in APOB, a gene previously associated with ataxia. CONCLUSIONS: These findings demonstrate that exome sequencing is an efficient and direct diagnostic tool for identifying the causes of complex and genetically heterogeneous neurodegenerative diseases, early-stage disease or cases with limited clinical data.

Microscopic polyangiitis presenting with peripheral and central neurological manifestations.

Although peripheral neuropathy is a common complication of microscopic angiitis, manifestations involving the muscle and the central nervous system have been rarely reported. We describe a 48-year-old man who rapidly developed a clinical picture of mononeuritis multiplex. A month after the appearance of the primary symptoms, he became comatose and had left hemiplegia in relation with a massive cerebral haematoma. Laboratory data revealed signs of inflammation, glomerular dysfunction with microhaematuria, and positive myeloperoxidase-antineutrophil cytoplasmic antibodies. The neuromuscular biopsy disclosed a small-vessel vasculitis, consisting with microscopic angiitis, associated with myositis and extensive axonal loss. The patient had surgical evacuation of the haematoma and received immunosuppressive therapy with good outcome. Thus, microscopic angiitis should be considered as a differential diagnosis in cases of myositis and intracerebral haemorrhage.

Molecular diagnosis of known recessive ataxias by homozygosity mapping with SNP arrays.

The diagnosis of rare inherited diseases is becoming more and more complex as an increasing number of clinical conditions appear to be genetically heterogeneous. Multigenic inheritance also applies to the autosomal recessive progressive cerebellar ataxias (ARCAs), for which 14 genes have been identified and more are expected to be discovered. We used homozygosity mapping as a guide for identification of the defective locus in patients with ARCA born from consanguineous parents. Patients from 97 families were analyzed with GeneChip Mapping 10K or 50K SNP Affymetrix microarrays. We identified six families homozygous for regions containing the autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) gene, two families homozygous for the ataxia-telangiectasia gene (ATM), two families homozygous for the ataxia with oculomotor apraxia type 1 (AOA1) gene, and one family homozygous for the AOA type 2 (AOA2) gene. Upon direct gene testing, we were able to identify a disease-related mutation in all families but one of the two kindred homozygous at the ATM locus. Although linkage analyses pointed to a single locus on chromosome 11q22.1-q23.1 for this family, clinical features, normal levels of serum alpha-foetoprotein as well as absence of mutations in the ATM gene rather suggest the existence of an additional ARCA-related gene in that interval. While the use of homozygosity mapping was very effective at pointing to the correct gene, it also suggests that the majority of patients harbor mutations either in the genes of the rare forms of ARCA or in genes yet to be identified.

Phenotype genotype analysis in 15 patients presenting a congenital myasthenic syndrome due to mutations in DOK7.

Congenital myasthenic syndromes (CMSs) are a heterogeneous group of diseases caused by genetic defects affecting neuromuscular transmission. Mutations of DOK7 have recently been described in recessive forms of CMS. Dok-7 is a cytoplasmic post-synaptic protein co-activator of the muscle-specific receptor-tyrosine kinase (MuSK) involved in neuromuscular synaptogenesis and maintenance. We report clinical, morphological and molecular data on 15 patients with mutations in DOK7. Eleven different mutations (5 novel) were identified and all patients but one were found to carry at least the common c.1124_1127dupTGCC mutation. Patients with DOK7 mutations have a particular limb-girdle pattern, without tubular aggregates but a frequent lipidosis on the muscle biopsy. Changes in pre- and post-synaptic compartments of the neuromuscular junction were also observed in muscle biopsies: terminal axons showed defective branching which resulted in a unique terminal axon contacting en passant postsynaptic cups. Clinical features, muscle biopsy findings or response to therapy were confusing in several patients. Characterization of this distinct phenotype is essential to provide clues for targeted genetic screening and to predict the therapeutic response to anticholinesterase treatments or ephedrine as has been suggested.

Characterization of DCTN1 genetic variability in neurodegeneration.

OBJECTIVE: Recently, mutations in DCTN1 were found to cause Perry syndrome, a parkinsonian disorder with TDP-43-positive pathology. Previously, mutations in DCTN1 were identified in a family with lower motor neuron disease, in amyotrophic lateral sclerosis (ALS), and in a family with ALS/frontotemporal dementia (FTD), suggesting a central role for DCTN1 in neurodegeneration. METHODS: In this study we sequenced all DCTN1 exons and exon-intron boundaries in 286 samples diagnosed with Parkinson disease (PD), frontotemporal lobar degeneration (FTLD), or ALS. RESULTS: This analysis revealed 36 novel variants (9 missense, 5 silent, and 22 noncoding). Segregation analysis in families and association studies in PD, FTLD, and ALS case-control series did not identify any variants segregating with disease or associated with increased disease risk. CONCLUSIONS: This study suggests that pathogenic mutations in DCTN1 are rare and do not play a common role in the development of Parkinson disease, frontotemporal lobar degeneration, or amyotrophic lateral sclerosis.

The CHRNE 1293insG founder mutation is a frequent cause of congenital myasthenia in North Africa.

OBJECTIVE: Mutations in various genes of the neuromuscular junction cause congenital myasthenic syndrome (CMS). A single truncating mutation (epsilon1293insG) in the acetylcholine receptor epsilon subunit gene (CHRNE) was most often identified in CMS families originating from North Africa and was possibly a founder mutation. METHODS: Twenty-three families were studied with an early onset form of CMS and originating from Tunisia, Algeria, Morocco, and Libya. Screening for the mutation epsilon1293insG was performed by direct sequencing. Haplotype analysis was done with 9 (CA)n repeat microsatellite markers and 6 SNPs flanking epsilon1293insG on chromosome 17p13-p12. Dating was calculated using the ESTIAGE method for rare genetic diseases. RESULTS: The epsilon1293insG mutation was identified in 14 families (about 60% of the initial 23). The expression of the CMS in affected members of these families was relatively homogeneous, without fetal involvement or being life-threatening, with moderate hypotonia and oculobulbar involvement, mild and stable disease course, and good response to cholinesterase inhibitors. Haplotype analysis revealed a common conserved haplotype encompassing a distance of 63 kb. The estimated age of the founder event was at least 700 years. CONCLUSIONS: These results strongly support the hypothesis that epsilon1293insG derives from an ancient single founder event in the North African population. Identification of founder mutations in isolated or inbred populations may have important implications in the context of molecular diagnosis and genetic counseling of patients and families by detection of heterozygous carriers.

Wilson's disease: appreciable improvement of sub-cortical white matter abnormalities after copper chelating treatment: five years follow-up.

Severe sub-cortical white matter abnormalities are unusual features in Wilson's disease and are reported to be poorly or not responsive to copper chelating therapy or to be worsened by it. We report on a 12-year-old boy with Wilson's disease and extensive sub-cortical white matter involvement. After five years of copper chelating therapy, an appreciable improvement of these lesions was obtained. The physiopathology of these unusual cerebral white matter abnormalities is discussed.

L-2-hydroxyglutaric aciduria: clinical and molecular study in three Tunisian families. Identification of a new mutation and inter-familial phenotype variability.

We report clinical and molecular studies in three unrelated Tunisian families containing seven patients with L2HGA. Although the age of onset is similar in all these patients at nearly 6 years, they progressively developed peculiar clinical phenotypes different from family to family. The three patients of family 1 showed mental retardation, epilepsy, cerebellar ataxia and pyramidal and pseudobulbar syndromes. The two patients of family 2 showed mental retardation and parkinsonism especially extrapyramidal stiffness, dystonia and myoclonus. The two patients of family 3 showed an intermediate phenotype; they share some clinical signs of the patients of family 1 (epilepsy, pyramidal and extrapyramidal syndromes) and some clinical signs of the patients of family 2 (extrapyramidal stiffness and dystonia). Molecular study identified a novel homozygous c.185C>A, p.A62D mutation on the L2HGDH gene in families 1 and 3 and the already known homozygous c.241A>G, p.K81E mutation in family 2. We suppose that the type of mutation in the L2HGDH gene does not play a complete role in the inter-familial phenotype variability. Disturbance of other unknown metabolic pathways related to L2HGA may contribute to this phenomenon.

Variable cardiac involvement in Tunisian siblings harboring FKRP gene mutations.

Mutations in the gene encoding fukutin-related protein (FKRP) cause limb-girdle muscular dystrophy 2I (LGMD2I) and congenital muscular dystrophy (MDC1C). Cardiac involvement was frequently reported with numerous mutations including C826A and 1364C > A mutations. The original Tunisian family with LGMD2I included 12 patients sharing the LGMD phenotype and homozygous to the 1486T > A mutation but who did not display any cardiac involvement. In this study, we report the clinical data, cardiac assessment and mutation analysis in four sibs belonging to a second Tunisian LGMD2I family. All patients showed the LGMD phenotype, the oldest brother and sister had mild cardiac involvement, whereas two twin sisters displayed severe cardiomyopathy leading to death. The patients shared the compound heterozygous 1486T > A, 1364C > A mutation in the FKRP gene suggesting that the association of a compound heterozygous state of mutation responsible for LGMD2I and the MDC1C phenotype could lead to cardiac involvement.

PINK1 mutations and parkinsonism.

BACKGROUND: PINK1 loss-of-function causes recessive, early-onset parkinsonism. In Tunisia there is a high rate of consanguineous marriage but PINK1 carrier frequency and disease prevalence have yet to be assessed. OBJECTIVES: The frequency of PINK1 mutations in familial parkinsonism, community-based patients with idiopathic Parkinson disease (PD) (non-familial PD), and control subjects was determined. Demographic and clinical characteristics of individuals with PINK1 homozygous or heterozygous variants, or without PINK1 mutations, were compared. METHODS: A total of 92 kindreds (with 208 affected and 340 unaffected subjects), 240 nonfamilial PD, and 368 control participants were recruited from the Institut National de Neurologie, Tunis. Clinical examinations included Hoehn &Yahr, UPDRS, and Epworth scales. PINK1 sequencing and dosage analysis was performed in familial index patients, the variants identified screened in all subjects. Parkin and LRRK2 genes were also examined. RESULTS: Four PINK1 homozygous mutations, three novel (Q129X, Q129fsX157, G440E, and one previously reported; Q456X), segregate with parkinsonism in 46 individuals in 14 of 92 families (15%). Six of 240 patients with nonfamilial PD were found with either homozygous Q456X or Q129X (2.5%) substitutions. In patients with familial disease, PINK1 homozygotes were younger at disease onset (36 +/- 12 years) than noncarriers (57 +/- 15 years) and more often had an akinetic-rigid presentation at examination and slow progression. CONCLUSIONS: Segregation of PINK1 mutations with parkinsonism within families, and frequency estimates within population controls, suggested only four PINK1 mutations were pathogenic. Several PINK1 sequence variants are potentially benign and there was no evidence that PINK1 heterozygosity increases susceptibility to idiopathic Parkinson disease.

Mathematical modeling of T-cell activation kinetic.

T-cell activation is a crucial step in mounting of the immune response. The dynamics of T-cell receptor (TCR) specific recognition of peptide presented by major histocompatibility complex (MHC) molecule decides the fate of the T cell. Several biochemical interactions interfere resulting in a highly complex mechanism that would be difficult to understand without computer help. The aim of the present study was to define a mathematical model in order to approach the kinetics of monoclonal T-cell-specific activation. The reaction scheme was first described and the model was tested using experimental parameters from the published data. Simulations were concordant with experimental data showing proportional decrease of membrane TCR and production of interleukin-2 (IL-2). Agonist and antagonist peptides induce different levels of intracellular signal that could make the yes or no decision for entry to cell cycle. Different conditions (peptide concentrations, initial TCR density and exogenous IL-2 levels) can be tested. Several parameters are missing for parameters estimation and adjustment before it could be adapted for a polyclonal T-cell reaction model. However, the model should be of interest in setting experiments, simulation of clinical responses and optimization of preventive or therapeutic immunotherapy.

A founding LRRK2 haplotype shared by Tunisian, US, European and Middle Eastern families with Parkinson's disease.

The Leucine-rich repeat kinase 2 (LRRK2) gene has been identified as a disease susceptibility gene for Parkinson's disease (PD), with G2019 (6055G>A) being the most frequent mutation. This mutation was present in 42% (38/91) of Tunisian families and 2% (1/39) of US families we have studied. A founding haplotype was identified in our data and it is shared by families from Tunisia, US, European and Middle Eastern countries. The most recent common founder of the mutation was dated to 2600 (95% CI: 1950-3850) years ago although additional studies are warranted to ensure an accurate age estimate for this mutation.

Osteoma of the calvaria in L-2-hydroxyglutaric aciduria.

L-2-Hydroxyglutaric aciduria (L-2-OHGA) is a rare autosomal recessive neurometabolic disease linked to chromosome 14q21.1 and is caused by mutations in the gene that most likely encodes L: -2-hydroxyglutarate dehydrogenase, which normally catalyses L: -2-hydroxyglutarate to alpha-ketoglutarate. It is characterized by progressive mental deterioration, pyramidal and cerebellar syndromes, macrocephaly and marked polycystic white-matter degeneration mainly involving frontal lobes. Brain tumours of variable nature have frequently been observed in L-2-OHGA. We report a patient affected by this disease who at the age of 20 years developed a bone tumour involving the right frontal region of the calvaria. He had first presented at the age of 10 years with psychomotor delay, clumsy gait and moderate mental impairment. Examination showed macrocephaly, cerebellar ataxia and quadripyramidal syndrome. Brain MRI showed low signal intensities on T1-weighted images and high signal intensities on T2-weighted images in cerebral subcortical white matter. Serum and urinary amino acid assay was normal. Urinary 2-hydroxyglutaric acid was 1418 mmol/mol creatinine (controls <25). Analysis of the L-2-hydroxyglutarate dehydrogenase gene revealed a homozygous mutation in exon 2 (A320G). At the age of 20 years, an osteoma of the right frontal bone was diagnosed. This finding reinforces the opinion concerning the association of L-2-OHGA and tumorigenesis and prompted us to verify the possible responsibility of some overproduced substances in this disease for the development of tumours and to look for any correlation between the type of mutation in the L-2-OHGA gene and the tumorigenic potential observed in some patients affected by this disease.

Reversible metronidazole-induced encephalopathy.

We report the neuroimaging findings of a case of reversible metronidazole-induced encephalopathy. Magnetic resonance imaging (MRI) demonstrated lesions in highly suggestive locations. Follow-up imaging performed 1 month after cessation of metronidazole therapy demonstrated resolution of imaging findings.

[Cardiac involvement in Emery-Dreifuss muscular dystrophy: a case report]. / L'atteinte cardiaque dans la dystrophie musculaire d'Emery-Dreifuss. A propos d'un cas.

Emery Dreifuss muscular dystrophy (EDMD) is an uncommon hereditary myopathy characterized by 3 symptoms: slow progressive muscular atrophy, muscular contractures and cardiac disease which affect prognosis. We report a 22 year-old patient with EDMD which shows the typical features of the associated dilated cardiomyopathy, ventricular arrhythmia, atrio-ventricular block, atrial standstill then atrial paralysis.

[A comparative study of clinical and paramedical aspects of multiple sclerosis in Tunisia]. / Etude comparative des aspects cliniques et paracliniques de la sclérose en plaques en Tunisie.

INTRODUCTION: Tunisia is considered as a low zone of prevalence for multiple sclerosis (MS). Consequently, only very few studies have taken an interest in this disorder in North Africa. The objective of this study was to compare the clinical and paraclinical parameters and the outcome of the disease in patients affected with MS in Tunisia during two periods (1974-1978 and 1996-2000) and to determine the incidence of the disease and the impact of the use of diagnostic criteria, including the MRI. PATIENTS AND METHODS: We report the results of a retrospective study concerning patients classified with MS and followed in the National Institute of Neurology in Tunis between 1974 and 2000, with 1058 records examined. We divided the patients into two groups belonging to two periods: Group I (1974-1978, 125 patients classified according to the McAlpine criteria) and Group II (1996-2000, 247 patients classified according to Poser's criteria. We compared the clinical and paraclinical parameters of the two groups. RESULTS: The incidence of the disease was evaluated at 1.3 per 100,000 individuals, placing Tunisia in the middle zone of prevalence. There was no significant difference in the mean age of onset (32.4+/-10.1 years) between the two groups. A slight male preponderance was observed in Group I (M/F sex ratio=1.25). The clinical outcome factors were age of onset after 40 years, pyramidal signs as the first symptom, and the progressive forms of the disease. Although Group II had an earlier diagnosis of the disease and a more systematic treatment of relapses, the functional outcome was similar between the two groups. CONCLUSION: MS in Tunisia has the same clinical characteristics and disease outcome as in other countries. The use of MRI allowed earlier diagnosis but did not increase the overall proportion of definite MS.