Therapeutic tools for familial ALS.

Familial ALS (FALS) accounts for 10 to 15% of ALS cases. In more than 70% of FALS patients, a causal gene is identified and animal models have been developed for a subset of them, mainly for the most frequently mutated genes. Therapeutic tools to treat those patients are dominated by gene-specific therapy and the most advanced approaches target the SOD1 gene mutations. Either by direct delivery of antisense oligonucleotides (ASO) or using viral vectors such as adenoviruses (AAV) to deliver ASOs, gene specific therapies have shown promising results in animal models. The recent use of subpial injections of AAV9+anti SOD1 ASO now shows that the disease is completely prevented or stopped in the animal, depending on the moment of injection, e.g., before or after disease onset. However, the use of viral vectors in humans seems to be limited at least by their immunogenicity. Antibody-based therapies are also efficient to treat animal models, but to a lesser extent. Most of the experiments targeted the SOD1 protein in its misfolded conformation. This approach seems better tolerated than the AAV one, an important limit being the choice of the epitope. Unexpectedly, some advances in treating the C9ORF72 animal model have been obtained using a modulation of microbiota, and this strategy has the great advantage to have an easy route of administration and a good safety profile. The landscape of experimental FALS treatment is rapidly evolving and results are promising. This is an important unmet need for ALS patients and several human phase I, II and III trials are ongoing.

An amyotrophic lateral sclerosis hot spot in the French Alps associated with genotoxic fungi.

Between 1990 and 2018, 14 cases of amyotrophic lateral sclerosis (ALS) were diagnosed in residents of, and in visitors with second homes to, a mountainous hamlet in the French Alps. Systematic investigation revealed a socio-professional network that connected ALS cases. Genetic risk factors for ALS were excluded. Several known environmental factors were scrutinized and eliminated, notably lead and other chemical contaminants in soil, water or home-grown vegetation used for food, radon and electromagnetic fields. Some lifestyle-related behavioral risk factors were identified: Prior to clinical onset of motor neuron disease, some patients had a high degree of athleticism and smoked tobacco. Recent investigations on site, based on a new hypothesis, showed that all patients had ingested wild mushrooms, notably poisonous False Morels. Half of the ALS cohort reported acute illness following Gyromitra gigas mushroom consumption. This finding supports the hypothesis that genotoxins of fungal origin may induce motor neuron degeneration.

Autosomal dominant SPG9: intrafamilial variability and onset during pregnancy.

INTRODUCTION: The ALDH18A1 gene, encoding delta-1-pyrroline-5-carboxylate synthase (P5CS), is responsible for an autosomal recessive disease with severe developmental delay; more recently, ALDH18A1 was found to be responsible for SPG9, an autosomal dominant (AD) spastic paraplegia. CASE REPORT: We report a three-generation family with AD SPG9, initially suspected because of low citrulline on fasting plasma amino acid chromatography (AAC). Interestingly, in two patients, the spastic paraplegia appeared during pregnancy. One subject presented a severe childhood-onset form while another subject had a mild late-onset disease. CONCLUSION: The description of this family is of particular interest: it highlights the possibility of transient or permanent aggravation of spastic paraplegia due to SPG9 during pregnancy, suggesting a direct link between neurological symptoms and amino acid defect in a period of higher requirements and the potential benefit of amino acid supplementation; it underscores the value of plasma citrulline on fasting plasma AAC as a biomarker for this disease; it shows the variable expression of the disease.

Pre-symptomatic diagnosis in ALS.

Pathophysiology of amyotrophic lateral sclerosis (ALS) remains partially understood even though it is accepted worldwide that motor neuron death results from a pluri-factorial process with a variable role of genetic factors. Although not distinguishable from a clinical point of view, familial forms of ALS (fALS, 10% of cases) and sporadic forms (sALS, 90% of cases) can be described. Since the identification of superoxide dismutase 1 gene (SOD1) mutations, more than 30 genes have been linked to fALS. Among these genes, five (C9ORF72, SOD1, TARDBP, FUS, TBK1) seem predominant with mutation frequencies of 40%, 20%, 5%, <5%, <5% in fALS and 6%, 3%, and <1% for the last three in sALS, respectively. The situation that classically leads to request genetic screening is the presence of a familial history of motor neuron disorders (MND) or fronto-temporal lobar dementia (FTLD). However, this dichotomy between fALS and sALS based on familial history can lead to mistakes since illegitimacy, ignorance of MND, FTD or psychiatric disorders within the family due to a familial censorship or lack of familial relationship, or a recessive autosomal inheritance could wrongly lead to failing to recognize a familial form. The significant development of genetic research and easier access to genetic tests in fALS increase the number of situations for which gene mutations are identified. The consequence is an increase in genetic requests from relatives of ALS patients who are eager to know their own genetic status and their own individual risk to develop ALS. Pre-symptomatic testing is thus becoming a daily issue in ALS Centers. This led us to propose a framework for such pre-symptomatic genetic testing for people at risk for developing ALS.

Serum neurofilament light chain at time of diagnosis is an independent prognostic factor of survival in amyotrophic lateral sclerosis.

BACKGROUND AND PURPOSE: The prognostic value of serum neurofilament light chain (sNfL), a biomarker of neurodegeneration, compared to other prognostic factors of amyotrophic lateral sclerosis (ALS) at the time of diagnosis, remains unclear. METHODS: Sera from ALS patients were prospectively collected at the first diagnostic visit in our centre. sNfL levels were determined by single molecule array in 207 ALS patients and in 21 healthy controls. The prognostic value of sNfL was compared with that of other known clinical prognostic factors using a Cox regression model and multivariate analysis. RESULTS: Serum neurofilament light chain levels were higher in ALS patients than in controls (P < 0.0001). Seven parameters were predictive of death in ALS: older age, bulbar onset, higher ALS Functional Rating Scale revised (ALSFRS-R) score, greater weight loss, lower maximal inspiratory pressure, forced vital capacity and higher sNfL levels. A Cox regression model showed that sNfL (P < 0.0001), weight loss (P = 0.040) and site at onset (P = 0.048) were independent predictive factors of death. In a sub-cohort restricted to 139 patients with complete spirometry data, sNfL level (P < 0.005) and forced vital capacity (P = 0.022) were independent factors predictive of death. In a subgroup of 142 patients in whom ALSFRS-R score was available at several time points, sNfL levels positively correlated with ALSFRS-R rate of decline (r = 0.571, P < 10-12 ). CONCLUSIONS: Higher sNfL concentration is a strong and independent prognostic factor of death in ALS as early as the time of diagnosis.

ALS and environment: Clues from spatial clustering?

A role for environmental factors in the etiology of amyotrophic lateral sclerocis (ALS) has been suspected for many years. A large body of work has implicated common exposures, conjugal cases, at-risk activities, heavy metals, organic solvents, and electric shocks, among others. One of the most demonstrative relationships between ALS and the environment is spatial clustering. We reviewed the most important and recent spatial clusters in a given area, whatever the geographical size, with either substantial epidemiological approaches or with highly significant associations, and with precise hypotheses. We present a broad, albeit incomplete overview of investigations in different areas, including examples of the difficulties and contradictions of some approaches. Most of the time, the implication of neurotoxins is suspected and, although not always strictly identified, some candidates are emerging: cycasin, MAM, L-BMAA, hydrazine, for example. One other important point is the possibility of interaction among risk/causal factors that increase the complexity of investigation. Additionally, with the exception of Western Pacific ALS, studies of spatial clustering are lacking a major methodological approach, namely a large cohort analysis extended over a long period of time, and probably for decades. Nevertheless, any spatial cluster needs to be identified, described and studied as deeply as possible to illuminate knowledge of the origin of this devastating disorder and to promote primary or secondary disease prevention.

Adult-onset spinal muscular atrophy: An update.

Spinal muscular atrophy (SMA) refers to a group of disorders affecting lower motor neurons. The age of onset of these disorders is variable, ranging from the neonatal period to adulthood. Over the last few years, there has been enormous progress in the description of new genes and phenotypes that throw new light on the molecular pathways involved in motor neuron degeneration. Advances in our understanding of the pathophysiology of the most frequent forms, SMA linked to SMN1 gene mutations and Kennedy disease, has led to the development of therapeutic strategies currently being tested in clinical trials. This report provides a general overview of the clinical features and pathophysiological mechanisms in adult-onset genetic SMA disorders in which the causative gene has been identified (SMN1-related SMA, Kennedy disease, CHCHD10, TRPV4, DYNC1H1 and BICD2). Sporadic lower motor neuron disease, also known as progressive muscular atrophy (PMA), is also discussed. The finding of TDP-43 aggregates in immunohistochemical studies of PMA strongly supports the idea that it is a phenotypic variant of amyotrophic lateral sclerosis (ALS).

Chitinase 3-like proteins as diagnostic and prognostic biomarkers of multiple sclerosis.

BACKGROUND: Despite sensitivity of MRI to diagnose multiple sclerosis (MS), prognostic biomarkers are still needed for optimized treatment. OBJECTIVE: The objective of this paper is to identify cerebrospinal fluid (CSF) diagnostic biomarkers of MS using quantitative proteomics and to analyze their expression at different disease stages. METHODS: We conducted differential analysis of the CSF proteome from control and relapsing-remitting MS (RRMS) patients followed by verification by ELISA of candidate biomarkers in CSF and serum in control, clinically isolated syndrome (CIS), RRMS and progressive MS (PMS) patients. RESULTS: Twenty-two of the 527 quantified proteins exhibited different abundances in control and RRMS CSF. These include chitinase 3-like protein 1 (CHI3L1) and 2 (CHI3L2), which showed a strong expression in brain of MS patients, especially in astrocytes and microglial cells from white matter plaques. CSF and serum CHI3L1 levels increased with the disease stage and CIS patients with high CSF (>189 ng/ml) and serum (>33 ng/ml) CHI3L1 converted more rapidly to RRMS (log rank test, p < 0.05 and p < 0.001, respectively). In contrast, CSF CHI3L2 levels were lower in PMS than in RRMS patients. Accordingly, CSF CHI3L1/CHI3L2 ratio accurately discriminated PMS from RRMS. CONCLUSIONS: CSF CHI3L1 and CHI3L2 and serum CHI3L1 might help to define MS disease stage and have a prognostic value in CIS.

Vitamin D is associated with degree of disability in patients with fully ambulatory relapsing-remitting multiple sclerosis.

BACKGROUND AND PURPOSE: Vitamin D deficiency is a recognized risk factor for multiple sclerosis (MS) and is associated with increased disease activity. It has also been proposed that the lower the vitamin D levels are, the higher is the handicap. METHODS: To refine the links between vitamin D insufficiency and disability in MS patients, a retrospective cohort analysis was performed including 181 patients prospectively followed without previous vitamin D supplementation, and age, gender, age at MS onset, MS type, MS activity, Expanded Disability Status Scale (EDSS) were analysed in correlation with plasma vitamin D levels. RESULTS: Vitamin D levels were significantly higher in relapsing-remitting MS than in progressive forms of MS in multivariate analyses adjusted for age, ethnicity, gender, disease duration and season (P = 0.0487). Overall, there was a negative correlation between vitamin D level and EDSS score (P = 0.0001, r = -0.33). In relapsing-remitting MS, vitamin D levels were only correlated with disability scores for EDSS < 4 (P = 0.0012). Patients with >20 ng/ml of vitamin D were 2.78 times more likely to have an EDSS < 4 (P = 0.0011, 95% confidence interval 1.49-5.00). CONCLUSION: Data support previous work suggesting that vitamin D deficiency is associated with higher risk of disability in MS. Vitamin D levels also correlated with the degree of disability in fully ambulatory patients with relapsing-remitting MS. These additional results support the pertinence of randomized controlled trials analysing the interest of an early vitamin D supplementation in MS patients to influence evolution of disability.

A prospective observational post-marketing study of natalizumab-treated multiple sclerosis patients: clinical, radiological and biological features and adverse events. The BIONAT cohort.

BACKGROUND AND PURPOSE: BIONAT is a French multicentric phase IV study of natalizumab (NTZ)-treated relapsing-remitting multiple sclerosis (MS) patients. The purpose of this study was to collect clinical, radiological and biological data on 1204 patients starting NTZ, and to evaluate the clinical/radiological response to NTZ after 2 years of treatment. METHODS: Patients starting NTZ at 18 French MS centres since June 2007 were included. Good response to NTZ was defined by the absence of clinical and radiological activity. Data analysed in this first report on the BIONAT study focus on patients who started NTZ at least 2 years ago (n = 793; BIONAT2Y ). RESULTS: NTZ was discontinued in 17.78% of BIONAT2Y. The proportion of patients without combined disease activity was 45.59% during the first two successive years of treatment. Systematic dosage of anti-NTZantibodies (Abs) detected only two supplementary patients with anti-NTZ Abs compared with strict application of recommendations. A significant decrease of IgG,M concentrations at 2 years of treatment was found. CONCLUSIONS: The efficacy of NTZ therapy on relapsing-remitting MS in a real life setting is confirmed in the BIONAT cohort. The next step will be the identification of biomarkers predicting response to NTZ therapy and adverse events.

[Awaji criteria: new diagnostic criteria for amyotrophic lateral sclerosis]. / Les critères d'Awaji: les nouveaux critères diagnostiques de la sclérose latérale amyotrophique.

Amyotrophic lateral sclerosis is the most common motor neuron disorder in adults. Although the diagnosis appears obvious in theory, clinical practice shows the contrary as diagnosis is delayed in many patients; the average time between symptom onset and diagnosis can reach 12 months. The delay can be explained by the variability of the clinical presentation and by the absence of diagnostic markers. In order to standardize diagnosis for enrollment in clinical research, diagnostic criteria for ALS were created and revisited during the last 20 years. In 2006, the Awaji criteria for the diagnosis of ALS were proposed, adding two major points to the diagnostic criteria: electromyography is considered equivalent to clinical examination for the identification of LMN signs and fasciculation potentials resume their prominent place in the diagnosis. Comparisons of the accuracy of the revisited El Escorial and Awaji criteria support improved diagnostic sensitivity without any effect on specificity with the new classification. The only weakness of the new classification involves patients with UMN signs in one region and LMN in two regions; these patients were previously classified as laboratory-supported probable ALS and currently as possible ALS, a lower level of diagnostic certainty. In all other instances the accuracy appears to be improved by the Awaji criteria. Nevertheless, there is a body of evidence suggesting the need for a revision of these new criteria, giving more weight to clinical and complementary findings of UMN involvement. The need to diagnose and treat ALS quickly could be facilitated by the inclusion of complementary investigations that detect UMN signs.

Phenotype and genotype analysis in amyotrophic lateral sclerosis with TARDBP gene mutations.

OBJECTIVE: To describe the phenotype and phenotype-genotype correlations in patients with amyotrophic lateral sclerosis (ALS) with TARDBP gene mutations. METHODS: French TARDBP+ patients with ALS (n = 28) were compared first to 3 cohorts: 737 sporadic ALS (SALS), 192 nonmutated familial ALS (FALS), and 58 SOD1 + FALS, and then to 117 TARDBP+ cases from the literature. Genotype-phenotype correlations were studied for the most frequent TARDBP mutations. RESULTS: In TARDBP+ patients, onset was earlier (p = 0.0003), upper limb (UL) onset was predominant (p = 0.002), and duration was longer (p = 0.0001) than in patients with SALS. TARDBP+ and SOD1+ groups had the longest duration but diverged for site of onset: 64.3% UL onset for TARDBP+ and 74.1% on lower limbs for SOD1+ (p < 0.0001). The clinical characteristics of our 28 patients were similar to the 117 cases from the literature. In Caucasians, 51.3% of had UL onset, while 58.8% of Asians had bulbar onset (p = 0.02). The type of mutation influenced survival (p < 0.0001), and the G298S1, lying in the TARDBP super rich glycine-residue domain, was associated with the worst survival (27 months). CONCLUSION: Differences in phenotype between the groups as well as the differential influence of TARBDP mutations on survival may help physicians in ALS management and allow refining the strategy of genetic diagnosis.

[Demyelinating disease affecting both central and peripheral nervous system]. / Maladie démyélinisante du système nerveux central et périphérique.

INTRODUCTION: Demyelinating disease affecting both the central and the peripheral nervous systems has rarely been reported. CASE REPORT: A 30-year-old man, presented with ataxia and diffuse areflexia due to polyneuropathy fullfilling demyelination criteria. His medical history was notable for central nervous system demyelination compatible with multiple sclerosis. He improved transiently with intravenous immunoglobulin and then stabilized with methotrexate. CONCLUSION: This case report distinguishes a new kind of inflammatory disease affecting both central and peripheral nervous system. It seems to be different from multiple sclerosis and chronic immune demyelinating polyneuropathy, because of high hyperproteinorachia and absence of oligoclonal bands in the cerebrospinal fluid.

APOE ε4 allele is associated with an increased risk of bulbar-onset amyotrophic lateral sclerosis in men.

OBJECTIVE: Several association studies have identified possible susceptibility factors for sporadic amyotrophic lateral sclerosis (SALS). Studies on the APOE gene provided conflicting results, especially about the effect on bulbar onset. We assessed the possible role of APOE gene in a large cohort of patients with ALS and matched controls. METHODS: The APOE alleles were determined in 1482 patients with SALS and 955 controls and analysed by univariate and multivariate statistics, taking into account gender, site-of-onset and age-at-onset. RESULTS: Patients with bulbar onset were more likely to be women [odds ratio (OR)=2.17; 95% CI: 1.74-2.72] and to be older (OR=3.47; 95% CI: 2.58-4.67). The ε4-carriers were more frequent in the bulbar-onset group than in the limb-onset group (OR=1.39 bulbar onset versus limb onset; 95% CI: 1.08-1.80) but this association was observed amongst men (OR=1.78; 95% CI: 1.25-2.53) and not women (OR=1.09; 95% CI: 0.75-1.59). CONCLUSION: Our study provides evidence for a contribution of the ε4 allele in the occurrence of bulbar-onset ALS amongst men. We propose that men are normally protected by androgens against bulbar onset and that the ε4 allele inhibits this protection, perhaps by interfering with the androgen pathway.

High-risk syndrome for neuromyelitis optica: a descriptive and comparative study.

BACKGROUND: Neuromyelitis optica (NMO) frequently begins with a monofocal episode of optic neuritis or myelitis. A concept named high-risk syndrome (HRS) for NMO has been proposed for patients with monofocal episodes and NMO-IgG antibodies. OBJECTIVE: To describe HRS patients and compare them with NMO patients. METHODS: We identified 30 patients with HRS: 18 with extensive myelitis (HRM) and 12 with optic neuritis (HRON), in a database pooling patients from 25 centres in France. Clinical, laboratory/magnetic resonance imaging (MRI) data and outcome were analysed and compared with a national cohort of 125 NMO patients extracted from the same database. RESULTS: Mean follow-up was 4.8 years. Mean age at onset was 42.8 years (range: 12.4-70) with a female:male ratio of 0.9. Asymptomatic lesions were report on visual evoked potentials in 4/8 tested HRM patients and on spinal cord MRI in 2/7 HRON patients. Three patients died, two owing to a cervical lesion. HRS and NMO patients had similar clinical/paraclinical data, except for a predominance of men in the HRS group and a later mean age at onset in the HRM subgroup. CONCLUSION: The description of HRS patients is compatible with a monofocal form of NMO. Asymptomatic lesions could be included in a new set of NMO diagnostic criteria.

Respiratory onset in an ALS family with L144F SOD1 mutation.

Familial amyotrophic lateral sclerosis (FALS) cases linked to SOD1 mutations may sometimes present with unusual clinical features such as pure lower motor neuron involvement or sensory signs. The authors describe a FALS pedigree with the L144F SOD1 mutation in which all cases had respiratory involvement as a first symptom. Although atypical clinical features are not rare in ALS families, this is the first pedigree with respiratory-onset in three affected members. This unusual presentation led to delayed diagnosis in the proband and highlights the fact that respiratory-onset can occur in familial ALS cases carrying SOD1 mutation.

Strategy for anti-aquaporin-4 auto-antibody identification and quantification using a new cell-based assay.

NMO-IgG is a specific biomarker of neuromyelitis optica (NMO) that targets the aquaporin-4 (AQP4) water channel protein. The current gold standard for NMO-IgG identification is indirect immunofluorescence (IIF). Our aim in this study was to develop a new quantitative cell-based assay (CBA) and to propose a rational strategy for anti-AQP4 Ab identification and quantification. We observed an excellent correlation between the CBA and IIF for NMO-IgG/anti-AQP4 detection. The CBA appeared more sensitive than IIF but on the other hand, IIF allows the simultaneous detection of various auto-Abs, underlining the complementarity between both methods. In conclusion, we propose to use IIF for the screening of patients at diagnosis in order to identify auto-Abs targeting the central nervous system. A highly sensitive, AQP4 specific and quantitative assay such as our CBA could be used thereafter to specifically identify the target of the Ab and to monitor its serum concentration under treatment.