Innovative Therapeutic Approaches in Congenital Myasthenic Syndromes.

Background and Objectives: To provide real-word clinical follow-up data on patients carrying variations of congenital myasthenic syndromes (CMS) and who respond to some innovative drugs. Methods: Patients recruited from the Neurology Department of the Mustapha Bacha university hospital in Algiers. Treated with innovative drugs, they were monitored and their clinical progress was evaluated on the basis of clinical arguments suggestive of CMSs, but also para clinical arguments (electromyography and genetic study). Results: Six patients carrying different mutations in different genes of CMSs were studied. They had different pathophysiologic profiles (slow or fast channel syndromes, low expressor of receptor). Their therapeutic management was based on innovative drugs, normally indicated in other, non-neurological pathologies. Their outcome was toward a clear clinical improvement. Discussion: This work relates the interest of proposing treatments (outside of Pyridostigmine) in the management of CMSs. These therapies can greatly modify the prognosis of patients suffering from this orphan disease. Classification of Evidence: This study provides Class IV evidence that for patients with congenital myasthenic syndromes, some innovative treatments are effective.

[Congenital myasthenic syndromes with kinetic abnormalities of the acetylcholine receptor]. / Les syndromes myasthéniques congénitaux avec anomalies cinétiques du récepteur à l'acétylcholine.

Congenital myasthenic syndromes (CMS) are genetically and phenotypically very heterogeneous conditions resulting in a defect in the neuromuscular transmission. Post-synaptic forms are the most frequent CMSs, and acetyl choline receptor (low expressor) deficiency is the most commonly involved pathophysiological mechanism. CMS with kinetic abnormalities of the acetylcholine receptor (AChr) are much rarer and can give rise to potentially life-threatening phenotypes. Among them, two types have been described: the slow channel syndrome (SCS) and the fast channel syndrome (FCS). Diagnosis and therapeutic management of such entities are specific to each type. In this work, we will illustrate the phenotypic aspects of CMS with kinetic abnormalities of the AChR by a narrative review of three Algerian families.

Title: Les syndromes myasthéniques congénitaux avec anomalies cinétiques du récepteur à l'acétylcholine. Abstract: Les syndromes myasthéniques congénitaux (SMC) sont des affections génétiquement et phénotypiquement très hétérogènes responsables d'un déficit de la transmission neuromusculaire. Les formes dites post-synaptiques sont les plus fréquentes des SMC, et parmi elles, le déficit en récepteur à l'acétylcholine (low expressor) est le mécanisme physiopathologique le plus souvent en cause. Les SMC avec anomalies cinétiques du récepteur à l'acétylcholine sont beaucoup plus rares et à l'origine de tableaux cliniques à l'issue parfois dramatique. On en dénombre deux types : le syndrome du canal lent et le syndrome du canal rapide. Leur diagnostic et leur prise en charge thérapeutique sont spécifiques à chaque type. Dans ce travail, nous détaillerons leurs aspects phénotypiques respectifs en les illustrant par les observations de trois familles algériennes.

Clinical management and disease-modifying treatment for amyotrophic lateral sclerosis in African hospital centers: the TROPALS study.

Objective: To assess the availability of health workers and medications for clinical management of amyotrophic lateral sclerosis (ALS) in African hospital centers. Availability and affordability analyses of disease-modifying treatments were performed. Methods: A multicenter observational study involving African hospitals was conducted. A standard questionnaire was developed based on the European Federation of the Neurological Societies (EFNS) guidelines. We collected data on multidisciplinary care and availability of medicines. The availability and affordability were evaluated according to the WHO guidelines. Results: Nine hospital centers from eight African countries participated. We observed a low degree of implementation of multidisciplinary care in ALS management. Riluzole was only available in centers from South Africa, Senegal, Tunisia, and Togo. This treatment was unaffordable and the adjusted price was highly variable among countries. The cost of riluzole was partly or fully covered by patients, which implies a substantial economic burden. Conclusion: Our findings strengthen the need to promote multidisciplinary care in the clinical management of ALS in Africa. Disease-modifying medication should be both available and affordable. Local and international collaboration is needed to improve ALS health care access in Africa.

[The high phenotypic variability of RYR1 gene mutations]. / La grande variabilité phénotypique des mutations du gène RYR1.

The RYR1 gene encodes the ryanodine-receptor 1, a key protein in the excitation-contraction coupling that takes place in muscle fibers. This receptor is the main channel responsible for calcium release from the endoplasmic reticulum [1]. A number of clinical phenotypes are linked to various mutations in this large gene as shown in a compilation established by ORPHANET (see table). In this work we describe two distinct, somewhat misleading, phenotypes in relation to pathogenic variants in this gene.

Title: La grande variabilité phénotypique des mutations du gène RYR1. Abstract: Le gène RYR1 (Ryanodine-Receptor-1) code pour une protéine-clé dans le processus de couplage excitation-contraction de la fibre musculaire. Ce récepteur est le principal canal de libération du calcium à partir du réticulum endoplasmique [1]. Un certain nombre de phénotypes cliniques sont imputables aux mutations de ce gène de grande taille comme rappelé dans la liste établie par ORPHANET (voir Encadré). Nous décrivons, dans ce travail, deux phénotypes distincts, et trompeurs à certains égards, en rapport avec des mutations de ce gène.

In-vitro immunomodulatory effects of nicotine on Nitric Oxide, interleukin 1ß and interleukin 37 production in human peripheral blood mononuclear cells (PBMC) from patients with Behçet disease.

Behçet's disease is a chronic systemic inflammatory disorder associated with a cytokine profile disruption and increased nitric oxide levels. In our current study we sought to evaluate the in-vitro modulatory effect of nicotine, the principal alkaloid of tobacco, on nitric oxide (NO), interleukin 1ß (IL-1ß) and interleukin 37 (IL-37) production during Behçet's disease. Peripheral blood mononuclear cells cultures were performed with or without nicotine (200 µg/ml). Culture supernatants were harvested after 24 h of incubation. NO, IL-1ß and IL-37 measurements were, respectively, performed by modified Griess method and ELISA sandwich. Our results showed that nicotine significantly reduced NO and IL-1ß levels in patients with Behçet's disease, while it increased IL-37 production. Our results showed no sex differences in the effects of nicotine on the production of nitric oxide and IL-1ß nor IL-37 in PBMC of patients. Our findings suggest that nicotine may provide a potential therapeutic strategy targeting inflammation during Behçet's disease.

Clinical features and prognosis of amyotrophic lateral sclerosis in Africa: the TROPALS study.

OBJECTIVE: We describe and compare the sociodemographic and clinical features, treatments, and prognoses and survival times of patients with amyotrophic lateral sclerosis (ALS) in Africa. METHODOLOGY: We conducted a multicentre, hospital-based cohort study in Africa. Patients with ALS diagnosed in the neurology departments of participating hospitals from 2005 to 2017 were included. Subgroup analysis was performed by subcontinent. Survival analyses were conducted using the Cox proportional hazards model. RESULTS: Nine centres from eight African countries participated. A total of 185 patients with ALS were included: 114 from Northern Africa, 41 from Western Africa and 30 from Southern Africa. A male predominance (male to female ratio 2.9) was evident. The median age at onset was 53.0 years (IQR 44.5-64.0 years). The onset was bulbar in 22.7%. Only 47 patients (26.3%) received riluzole, mainly in Northern and Western Africa. The median survival from the time of diagnosis was 14.0 months (95% CI 10.7 to 17.2 months). The median survival was longer in Northern Africa (19.0 months, 95% CI 10.8 to 27.2 months) than in Western (4.0 months, 95% CI 0.8 to 7.1 months) and Southern (11.0 months, 95% CI 5.6 to 16.4 months) Africa (Breslow test, p<0.0001). Both subcontinental location and riluzole treatment independently affected survival. CONCLUSION: More African patients with ALS were male and younger and exhibited a lower proportion of bulbar onset compared with patients with ALS from Western nations. Survival was consistent with that in Western registers but far shorter than what would be expected for young patients with ALS. The research improves our understanding of the disease in Africa.

Validation of a clinical practice-based algorithm for the diagnosis of autosomal recessive cerebellar ataxias based on NGS identified cases.

Establishing a molecular diagnosis of autosomal recessive cerebellar ataxias (ARCA) is challenging due to phenotype and genotype heterogeneity. We report the validation of a previously published clinical practice-based algorithm to diagnose ARCA. Two assessors performed a blind analysis to determine the most probable mutated gene based on comprehensive clinical and paraclinical data, without knowing the molecular diagnosis of 23 patients diagnosed by targeted capture of 57 ataxia genes and high-throughput sequencing coming from a 145 patients series. The correct gene was predicted in 61 and 78 % of the cases by the two assessors, respectively. There was a high inter-rater agreement [K = 0.85 (0.55-0.98) p < 0.001] confirming the algorithm's reproducibility. Phenotyping patients with proper clinical examination, imaging, biochemical investigations and nerve conduction studies remain crucial for the guidance of molecular analysis and to interpret next generation sequencing results. The proposed algorithm should be helpful for diagnosing ARCA in clinical practice.

Molecular and clinical study of a cohort of 110 Algerian patients with autosomal recessive ataxia.

BACKGROUND: Autosomal recessive cerebellar ataxias (ARCA) are a complex group of neurodegenerative disorders with great genetic and phenotypic heterogeneity, over 30 genes/loci have been associated with more than 20 different clinical forms of ARCA. Genetic heterogeneity combined with highly variable clinical expression of the cerebellar symptoms and overlapping features complicate furthermore the etiological diagnosis of ARCA. The determination of the most frequent mutations and corresponding ataxias, as well as particular features specific to a population, are mandatory to facilitate and speed up the diagnosis process, especially when an appropriate treatment is available. METHODS: We explored 166 patients (115 families) refered to the neurology units of Algiers central hospitals (Algeria) with a cerebellar ataxia phenotype segregating as an autosomal recessive pattern of inheritance. Genomic DNA was extracted from peripheral blood samples and mutational screening was performed by PCR and direct sequencing or by targeted genomic capture and massive parallel sequencing of 57 genes associated with inherited cerebellar ataxia phenotypes. RESULTS: In this work we report the clinical and molecular results obtained on a large cohort of Algerian patients (110 patients/76 families) with genetically determined autosomal recessive ataxia, representing 9 different types of ARCA and 23 different mutations, including 6 novel ones. The five most common ARCA in this cohort were Friedreich ataxia, ataxia with isolated vitamin E deficiency, ataxia with oculomotor apraxia type 2, autosomal recessive spastic ataxia of Charlevoix-Saguenay and ataxia with oculomotor apraxia type 1. CONCLUSION: We report here a large cohort of patients with genetically determined autosomal recessive ataxia and the first study of the genetic context of ARCA in Algeria. This study showed that in Algerian patients, the two most common types of ataxia (Friedreich ataxia and ataxia with isolated vitamin E deficiency) coexist with forms that may be less common or underdiagnosed. To refine the genotype/phenotype correlation in rare and heteregeneous diseases as autosomal recessive ataxias, more extensive epidemiological investigations and reports are necessary as well as more accurate and detailed clinical characterizations. The use of standardized clinical and molecular protocols would thus enable a better knowledge of the different forms of ARCA.

ADCK3, an ancestral kinase, is mutated in a form of recessive ataxia associated with coenzyme Q10 deficiency.

Muscle coenzyme Q(10) (CoQ(10) or ubiquinone) deficiency has been identified in more than 20 patients with presumed autosomal-recessive ataxia. However, mutations in genes required for CoQ(10) biosynthetic pathway have been identified only in patients with infantile-onset multisystemic diseases or isolated nephropathy. Our SNP-based genome-wide scan in a large consanguineous family revealed a locus for autosomal-recessive ataxia at chromosome 1q41. The causative mutation is a homozygous splice-site mutation in the aarF-domain-containing kinase 3 gene (ADCK3). Five additional mutations in ADCK3 were found in three patients with sporadic ataxia, including one known to have CoQ(10) deficiency in muscle. All of the patients have childhood-onset cerebellar ataxia with slow progression, and three of six have mildly elevated lactate levels. ADCK3 is a mitochondrial protein homologous to the yeast COQ8 and the bacterial UbiB proteins, which are required for CoQ biosynthesis. Three out of four patients tested showed a low endogenous pool of CoQ(10) in their fibroblasts or lymphoblasts, and two out of three patients showed impaired ubiquinone synthesis, strongly suggesting that ADCK3 is also involved in CoQ(10) biosynthesis. The deleterious nature of the three identified missense changes was confirmed by the introduction of them at the corresponding positions of the yeast COQ8 gene. Finally, a phylogenetic analysis shows that ADCK3 belongs to the family of atypical kinases, which includes phosphoinositide and choline kinases, suggesting that ADCK3 plays an indirect regulatory role in ubiquinone biosynthesis possibly as part of a feedback loop that regulates ATP production.