Dysregulation of muscle cholesterol transport in amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder affecting motor neurons, with a typical lifespan of 3-5 years. Altered metabolism is a key feature of ALS that strongly influences prognosis, with an increase in whole-body energy expenditure and changes in skeletal muscle metabolism, including greater reliance on fat oxidation. Dyslipidemia has been described in ALS as part of the metabolic dysregulation, but its role in the pathophysiology of the disease remains controversial. Among the lipids, cholesterol is of particular interest as a vital component of cell membranes, playing a key role in signal transduction and mitochondrial function in muscle. The aim of this study was to investigate whether motor dysfunction in ALS might be associated with dysregulation of muscle cholesterol metabolism. We determined cholesterol content and analyzed the expression of key determinants of the cholesterol metabolism pathway in muscle biopsies from thirteen ALS patients and ten asymptomatic ALS-mutation gene carriers compared to sixteen controls. Using human control primary myotubes, we further investigated the potential contribution of cholesterol dyshomeostasis to reliance on mitochondrial fatty acid. We found that cholesterol accumulates in the skeletal muscle of ALS patients and that cholesterol overload significantly correlates with disease severity evaluated by the Revised ALS Functional Rating Scale. These defects are associated with overexpression of the genes of the lysosomal cholesterol transporters Niemann-Pick type C1 (NPC1) and 2 (NPC2), which are required for cholesterol transfer from late endosomes/lysosomes to cellular membranes. Most notably, a significant increase in NPC2 mRNA levels could be detected in muscle samples from asymptomatic ALS-mutation carriers, long before disease onset. We found that filipin-stained unesterified cholesterol accumulated in the lysosomal compartment in ALS muscle samples, suggesting dysfunction of the NPC1/2 system. Accordingly, we report here that experimental NPC1 inhibition or lysosomal pH alteration in human primary myotubes was sufficient to induce the overexpression of NPC1 and NPC2 mRNA. Finally, acute NPC1 inhibition in human control myotubes induced a shift towards a preferential use of fatty acids, thus reproducing the metabolic defect characteristic of ALS muscle. We conclude that cholesterol homeostasis is dysregulated in ALS muscle from the presymptomatic stage. Targeting NPC1/2 dysfunction may be a new therapeutic strategy for ALS to restore muscle energy metabolism and slow motor symptom progression.

Cognitive impairment in children and adults with cerebrotendinous xanthomatosis: A French cohort study.

Cerebrotendinous xanthomatosis is a rare and treatable metabolic disorder related to the accumulation of cholestanol. This disorder is primarily associated with motor and cognitive impairments, although the latter has not been extensively characterized. The objectives of this work were to define the cognitive profile found in cerebrotendinous xanthomatosis patients, investigate the progression of cognitive impairment over time, and search for radio-clinical correlations. Through a multicentric chart review study, we collected cognitive and radiological data from nine children and eighteen adults with genetically proven cerebrotendinous xanthomatosis. We performed a volumetric and morphological analysis of the brain magnetic resonance imaging. In our cohort, 44% (4/9) of children and 78% (14/18) of adults exhibited cognitive impairment that can be severe. The study revealed a significant impairment in various cognitive domains, specifically executive, attentional, language, and visuo-spatial. Among adults, 16% (3/18) developed dementia after age 50. These three patients had delayed chenodeoxycholic acid treatment and important cerebral atrophy. Besides these three cases of late-onset cognitive decline, Mini-Mental State Evaluation was generally stable, suggesting cognitive impairment due to a neurodevelopmental disorder and persisting in adulthood. Cognitive impairment was less common in children, possibly related to early chenodeoxycholic acid treatment in our cohort. The severity of magnetic resonance imaging abnormalities did not predict cognitive impairment in patients. Overall, in cerebrotendinous xanthomatosis, cognitive impairment can be severe and mainly neurodevelopmental. Early chenodeoxycholic acid treatment might be associated with a reduced risk of cognitive decline.

Impact of a frequent nearsplice SOD1 variant in amyotrophic lateral sclerosis: optimising SOD1 genetic screening for gene therapy opportunities.

OBJECTIVE: Mutations in superoxide dismutase 1 gene (SOD1), encoding copper/zinc superoxide dismutase protein, are the second most frequent high penetrant genetic cause for amyotrophic lateral sclerosis (ALS) motor neuron disease in populations of European descent. More than 200 missense variants are reported along the SOD1 protein. To limit the production of these aberrant and deleterious SOD1 species, antisense oligonucleotide approaches have recently emerged and showed promising effects in clinical trials. To offer the possibility to any patient with SOD1-ALS to benefit of such a gene therapy, it is necessary to ascertain whether any variant of unknown significance (VUS), detected for example in SOD1 non-coding sequences, is pathogenic. METHODS: We analysed SOD1 mutation distribution after SOD1 sequencing in a large cohort of 470 French familial ALS (fALS) index cases. RESULTS: We identified a total of 27 SOD1 variants in 38 families including two SOD1 variants located in nearsplice or intronic regions of the gene. The pathogenicity of the c.358-10T>G nearsplice SOD1 variant was corroborated based on its high frequency (as the second most frequent SOD1 variant) in French fALS, the segregation analysis confirmed in eight affected members of a large pedigree, the typical SOD1-related phenotype observed (with lower limb onset and prominent lower motor neuron involvement), and findings on postmortem tissues showing SOD1 misaccumulation. CONCLUSIONS: Our results highlighted nearsplice/intronic mutations in SOD1 are responsible for a significant portion of French fALS and suggested the systematic analysis of the SOD1 mRNA sequence could become the method of choice for SOD1 screening, not to miss these specific cases.

Treatment with chenodeoxycholic acid in cerebrotendinous xanthomatosis: clinical, neurophysiological, and quantitative brain structural outcomes.

BACKGROUND: Cerebrotendinous xanthomatosis (CTX) is a rare neurodegenerative disease related to sterols metabolism. It affects both central and peripheral nervous systems but treatment with chenodeoxycholic acid (CDCA) has been reported to stabilize clinical scores and improve nerve conduction parameters. Few quantitative brain structural studies have been conducted to assess the effect of CDCA in CTX. METHODS AND RESULTS: We collected retrospectively clinical, neurophysiological, and quantitative brain structural data in a cohort of 14 patients with CTX treated by CDCA over a mean period of 5 years. Plasma cholestanol levels normalized under treatment with CDCA within a few months. We observed a significant clinical improvement in patients up to 25 years old, whose treatment was initiated less than 15 years after the onset of neurological symptoms. Conversely, patients whose treatment was initiated more than 25 years after neurological disease onset continued their clinical deterioration. Eleven patients presented with a length-dependent peripheral neuropathy, whose electrophysiological parameters improved significantly under CDCA. Volumetric analyses in a subset of patients showed no overt volume loss under CDCA. Moreover, diffusion weighted imaging showed improved fiber integrity of the ponto-cerebellar and the internal capsule with CDCA. CDCA was well tolerated in all patients with CTX. CONCLUSION: CDCA may reverse the pathophysiological process in patients with CTX, especially if treatment is initiated early in the disease process. Besides tendon xanthoma, this study stresses the need to consider plasma cholestanol measurement in any patient with infantile chronic diarrhea and/or jaundice, juvenile cataract, learning disability and/or autism spectrum disorder, pyramidal signs, cerebellar syndrome or peripheral neuropathy.

Involvement of peripheral III nerve in multiple sclerosis patient: Report of a new case and discussion of the underlying mechanism.

Multiple sclerosis (MS) is a chronic disorder that affects the central nervous system myelin. However, a few radiological cases have documented an involvement of peripheral cranial nerves, within the subarachnoid space, in MS patients. We report the case of a 36-year-old female with a history of relapsing-remitting (RR) MS who consulted for a subacute complete paralysis of the right III nerve. Magnetic resonance imaging (MRI) examination showed enhancement and thickening of the cisternal right III nerve, in continuity with a linear, mesencephalic, acute demyelinating lesion. Radiological involvement of the cisternal part of III nerve has been reported only once in MS patients. Radiological involvement of the cisternal part of V nerve occurs more frequently, in almost 3% of MS patients. In both situations, the presence of a central demyelinating lesion, in continuity with the enhancement of the peripheral nerve, suggests that peripheral nerve damage is a secondary process, rather than a primary target of demyelination.

Cerebrospinal fluid metabolomics highlights dysregulation of energy metabolism in overt hepatic encephalopathy.

BACKGROUND & AIMS: Hepatic encephalopathy (HE) is a neurological complication observed in patients with liver disease and/or porto-systemic shunt. The proportion of cirrhotic patients developing overt HE is about 20%, and 60-80% of cirrhotic patients exhibit mild cognitive impairment potentially related to minimal HE. However, the pathophysiological mechanisms of HE remain poorly understood. In this context, metabolomics was used to highlight dysfunction of metabolic pathways in cerebrospinal fluid (CSF) samples of patients suffering from HE. METHODS: CSF samples were collected in 27 control patients without any proven neurological disease and 14 patients with symptoms of HE. Plasma samples were obtained from control patients, and from cirrhotic patients with and without HE. Metabolomic analysis was performed using liquid chromatography coupled to high-resolution mass spectrometry. RESULTS: Concentrations of 73 CSF metabolites, including amino acids, acylcarnitines, bile acids and nucleosides, were altered in HE patients. Accumulation of acetylated compounds, which could be due to a defect of the Krebs cycle in HE patients, is reported for the first time. Furthermore, analysis of plasma samples showed that concentrations of metabolites involved in ammonia, amino-acid and energy metabolism are specifically and significantly increased in CSF samples of HE patients. Lastly, several drugs were detected in CSF samples and could partially explain worsening of neurological symptoms for some patients. CONCLUSION: By enabling the simultaneous monitoring of a large set of metabolites in HE patients, CSF metabolomics highlighted alterations of metabolic pathways linked to energy metabolism that were not observed in plasma samples. LAY SUMMARY: CSF metabolomics provides a global picture of altered metabolic pathways in CSF samples of HE patients and highlights alterations of metabolic pathways linked to energy metabolism that are not observed in plasma samples.

Heterozygous HTRA1 mutations are associated with autosomal dominant cerebral small vessel disease.

Cerebral small vessel disease represents a heterogeneous group of disorders leading to stroke and cognitive impairment. While most small vessel diseases appear sporadic and related to age and hypertension, several early-onset monogenic forms have also been reported. However, only a minority of patients with familial small vessel disease carry mutations in one of known small vessel disease genes. We used whole exome sequencing to identify candidate genes in an autosomal dominant small vessel disease family in which known small vessel disease genes had been excluded, and subsequently screened all candidate genes in 201 unrelated probands with a familial small vessel disease of unknown aetiology, using high throughput multiplex polymerase chain reaction and next generation sequencing. A heterozygous HTRA1 variant (R166L), absent from 1000 Genomes and Exome Variant Server databases and predicted to be deleterious by in silico tools, was identified in all affected members of the index family. Ten probands of 201 additional unrelated and affected probands (4.97%) harboured a heterozygous HTRA1 mutation predicted to be damaging. There was a highly significant difference in the number of likely deleterious variants in cases compared to controls (P = 4.2 × 10(-6); odds ratio = 15.4; 95% confidence interval = 4.9-45.5), strongly suggesting causality. Seven of these variants were located within or close to the HTRA1 protease domain, three were in the N-terminal domain of unknown function and one in the C-terminal PDZ domain. In vitro activity analysis of HTRA1 mutants demonstrated a loss of function effect. Clinical features of this autosomal dominant small vessel disease differ from those of CARASIL and CADASIL by a later age of onset and the absence of the typical extraneurological features of CARASIL. They are similar to those of sporadic small vessel disease, except for their familial nature. Our data demonstrate that heterozygous HTRA1 mutations are an important cause of familial small vessel disease, and that screening of HTRA1 should be considered in all patients with a hereditary small vessel disease of unknown aetiology.

Pearls & Oy-sters: Spinal Cord Candidiasis Linked to CARD9 Deficiency Masquerading as a Longitudinally Extensive Transverse Myelitis.

Candida spp. myelopathies are very rare. We report a case of subacute longitudinally extensive transverse myelitis in an apparently immunocompetent 55-year-old man. After a negative infectious workup, corticosteroids and plasma exchange were initiated. Although there was a transient initial improvement, symptoms then worsened, and the lumbar puncture was repeated. Candida albicans was isolated in the CSF, and a diagnosis of spinal cord candidiasis was made. Gene panel sequencing for inborn immune deficiencies identified a homozygous disease-causing CARD9 variant. Despite antifungal treatment, necrotic myelitis, meningoencephalitis, and cerebral vasculitis developed. Fungal spinal cord infections can mimic inflammatory myelitis, and beta-D-glucan testing of both serum and CSF may help narrow down the diagnosis. In cases of severe or unexpected invasive Candida spp. infection, even adults and apparently immunocompetent patients should be screened for inborn immune deficiencies and CARD9 deficiency in particular.

Clinical trials in pediatric ALS: a TRICALS feasibility study.

Background: Pediatric investigation plans (PIPs) describe how adult drugs can be studied in children. In 2015, PIPs for Amyotrophic Lateral Sclerosis (ALS) became mandatory for European marketing-authorization of adult treatments, unless a waiver is granted by the European Medicines Agency (EMA).Objective: To assess the feasibility of clinical studies on the effect of therapy in children (<18 years) with ALS in Europe.Methods: The EMA database was searched for submitted PIPs in ALS. A questionnaire was sent to 58 European ALS centers to collect the prevalence of pediatric ALS during the past ten years, the recruitment potential for future pediatric trials, and opinions of ALS experts concerning a waiver for ALS.Results: Four PIPs were identified; two were waived and two are planned for the future. In total, 49 (84.5%) centers responded to the questionnaire. The diagnosis of 44,858 patients with ALS was reported by 46 sites; 39 of the patients had an onset < 18 years (prevalence of 0.008 cases per 100,000 or 0.087% of all diagnosed patients). The estimated recruitment potential (47 sites) was 26 pediatric patients within five years. A majority of ALS experts (75.5%) recommend a waiver should apply for ALS due to the low prevalence of pediatric ALS.Conclusions: ALS with an onset before 18 years is extremely rare and may be a distinct entity from adult ALS. Conducting studies on the effect of disease-modifying therapy in pediatric ALS may involve lengthy recruitment periods, high costs, ethical/legal implications, challenges in trial design and limited information.

Four-dimensional digital subtraction angiography for exploration of spinal cord vascular malformations: preliminary experience.

BACKGROUND: The precise understanding of the angioarchitecture of spinal vascular malformations (SVMs) is often difficult to reach with conventional digital subtraction angiography (DSA). The purpose of our study was to evaluate the potential of four-dimensional DSA (4D-DSA) (Siemens Healthcare) in the exploration of SVMs. METHODS: We retrospectively studied all patients who underwent spinal DSA, including 4D-DSA acquisition, from July 2018 to June 2019 at a single institution. All spinal DSA acquisitions were performed under general anesthesia. 4D-DSA acquisitions were acquired with the protocol '12 s DSA Dyna4D Neuro'. 12 mL of iodixanol 320 mg iodine/mL were injected via a 5 F catheter (1 mL/s during the 12 s 4D-DSA acquisition). Inter-rater (three independent reviewers) and intermodality agreements were assessed. RESULTS: Nine consecutive patients (six men, three women, mean age 55.3±19.8 years) with 10 SVMs (spinal dural arteriovenous fistulas n=3, spinal epidural arteriovenous fistulas n=2, spinal pial arteriovenous fistulas n=2, and spinal arteriovenous malformations n=2; one patient had two synchronous pial fistulas) had spinal DSA, including 4D-DSA acquisition. Inter-rater agreement was good and moderate for the venous drainage pattern and the SVM subtype, respectively. In 9 of 10 cases, the quality of the acquisition was graded as good. Satisfactory concordance between 4D-DSA and the selective microcatheterization was observed in 90% of cases for the location of the shunt point. CONCLUSION: 4D-DSA acquisition may be helpful for a better understanding of the angioarchitecture of SVMs. Larger series are warranted to confirm these preliminary results.

Who and Why? Requests for Presymptomatic Genetic Testing for Amyotrophic Lateral Sclerosis/Frontotemporal Dementia vs Huntington Disease.

OBJECTIVE: We aimed to describe the population of subjects seeking presymptomatic counseling for amyotrophic lateral sclerosis and/or frontotemporal dementia (ALS/FTD) and compared them with those demanding the well-established presymptomatic test for Huntington disease (HD). METHODS: We retrospectively examined the requests of a cohort of individuals at risk of familial ALS/FTD and 1 at risk of HD over the same time frame of 11 years. The individuals were seen in the referral center of our neurogenetics unit. RESULTS: Of the 106 presymptomatic testing (PT) requests from subjects at risk of ALS/FTD, 65% were seen in the last 3 years. Over two-thirds of the subjects were at risk of carrying mutations responsible for ALS, FTD, or both. Sixty-two percent of the subjects came from families with a known hexanucleotide repeat expansion in C9ORF72. During the same period, we counseled 840 subjects at risk of HD. Subjects at risk of ALS/FTD had the presymptomatic test significantly sooner after being aware of their risk, but were older than those at risk of HD. The youngest subjects requesting the test had the highest disease load in the family (p < 0.05). CONCLUSIONS: Demands for PT for ALS/FTD have been increasingly growing, particularly since the discovery of the C9ORF72 gene. The major specificity of the genetic counseling for these diseases is the unpredictability of the clinical phenotype for most of the genes involved. Awareness of this added uncertainty does not prevent individuals from taking the test, as the dropout rate is not higher than that for HD.

Development of new outcome measures for adult SMA type III and IV: a multimodal longitudinal study.

OBJECTIVE: The aim of this study was the comprehensive characterisation of longitudinal clinical, electrophysiological and neuroimaging measures in type III and IV adult spinal muscular atrophy (SMA) with a view to propose objective monitoring markers for future clinical trials. METHODS: Fourteen type III or IV SMA patients underwent standardised assessments including muscle strength testing, functional evaluation (SMAFRS and MFM), MUNIX (abductor pollicis brevis, APB; abductor digiti minimi, ADM; deltoid; tibialis anterior, TA; trapezius) and quantitative cervical spinal cord MRI to appraise segmental grey and white matter atrophy. Patients underwent a follow-up assessment with the same protocol 24 months later. Longitudinal comparisons were conducted using the Wilcoxon-test for matched data. Responsiveness was estimated using standardized response means (SRM) and a composite score was generated based on the three most significant variables. RESULTS: Significant functional decline was observed based on SMAFRS (p = 0.019), pinch and knee flexion strength (p = 0.030 and 0.027), MUNIX and MUSIX value in the ADM (p = 0.0006 and 0.043) and in TA muscle (p = 0.025). No significant differences were observed based on cervical MRI measures. A significant reduction was detected in the composite score (p = 0.0005, SRM = -1.52), which was the most responsive variable and required a smaller number of patients than single variables in the estimation of sample size for clinical trials. CONCLUSIONS: Quantitative strength testing, SMAFRS and MUNIX readily capture disease progression in adult SMA patients. Composite multimodal scores increase predictive value and may reduce sample size requirements in clinical trials.

Genetic screening of ANXA11 revealed novel mutations linked to amyotrophic lateral sclerosis.

ANXA11 mutations have previously been discovered in amyotrophic lateral sclerosis (ALS) motor neuron disease. To confirm the contribution of ANXA11 mutations to ALS, a large exome data set obtained from 330 French patients, including 150 familial ALS index cases and 180 sporadic ALS cases, was analyzed, leading to the identification of 3 rare ANXA11 variants in 5 patients. The novel p.L254V variant was associated with early onset sporadic ALS. The novel p.D40Y mutation and the p.G38R variant concerned patients with predominant pyramidal tract involvement and cognitive decline. Neuropathologic findings in a p.G38R carrier associated the presence of ALS typical inclusions within the spinal cord, massive degeneration of the lateral tracts, and type A frontotemporal lobar degeneration. This mutant form of annexin A11 accumulated in various brain regions and in spinal cord motor neurons, although its stability was decreased in patients' lymphoblasts. Because most ANXA11 inclusions were not colocalized with transactive response DNA-binding protein 43 or p62 deposits, ANXA11 aggregation does not seem mandatory to trigger neurodegeneration with additional participants/partner proteins that could intervene.

Predictive factors for prognosis after gastrostomy placement in routine non-invasive ventilation users ALS patients.

Due to the expanding use of non-invasive ventilation (NIV) in amyotrophic lateral sclerosis (ALS), the question of enteral nutrition is increasingly raised in NIV users ALS patients. Here, we aimed to determine the prognostic factors for survival after gastrostomy placement in routine NIV users, taking into consideration ventilator dependence. Ninety-two routine NIV users ALS patients, who underwent gastrostomy insertion for severe dysphagia and/or weight loss, were included. We used a Cox proportional hazards model to identify factors affecting survival and compared time from gastrostomy to death and 30-day mortality rate between dependent (daily use ≥ 16 h) and non-dependent NIV users. The hazard of death after gastrostomy was significantly affected by 3 factors: age at onset (HR 1.047, p = 0.006), body mass index < 20 kg/m2 at the time of gastrostomy placement (HR 2.012, p = 0.016) and recurrent accumulation of airway secretions (HR 2.614, p = 0.001). Mean time from gastrostomy to death was significantly shorter in the dependent than in the non-dependent NIV users group (133 vs. 250 days, p = 0.04). The 30-day mortality rate was significantly higher in dependent NIV users (21.4% vs. 2.8%, p = 0.03). Pre-operative ventilator dependence and airway secretion accumulation are associated with worse prognosis and should be key decision-making criteria when considering gastrostomy tube placement in NIV users ALS patients.

Homoplasmic deleterious MT-ATP6/8 mutations in adult patients.

To address the frequency of complex V defects, we systematically sequenced MT-ATP6/8 genes in 512 consecutive patients. We performed functional analysis in muscle or fibroblasts for 12 out of 27 putative homoplasmic mutations and in cybrids for four. Fibroblasts, muscle and cybrids with known deleterious mutations underwent parallel analysis. It included oxidative phosphorylation spectrophotometric assays, western blots, structural analysis, ATP production, glycolysis and cell proliferation evaluation. We demonstrated the deleterious nature of three original mutations. Striking gradation in severity of the mutations consequences and differences between muscle, fibroblasts and cybrids implied a likely under-diagnosis of human complex V defects.

Cursive Eye-Writing With Smooth-Pursuit Eye-Movement Is Possible in Subjects With Amyotrophic Lateral Sclerosis.

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder causing a progressive motor weakness of all voluntary muscles, whose progression challenges communication modalities such as handwriting or speech. The current study investigated whether ALS subjects can use Eye-On-Line (EOL), a novel eye-operated communication device allowing, after training, to voluntarily control smooth-pursuit eye-movements (SPEM) so as to eye-write in cursive. To that aim, ALS participants (n = 12) with preserved eye-movements but impaired handwriting were trained during six on-site visits. The primary outcome of the study was the recognition of eye-written digits (0-9) from ALS and healthy control subjects by naïve "readers." Changes in oculomotor performance and the safety of EOL were also evaluated. At the end of the program, 69.4% of the eye-written digits from 11 ALS subjects were recognized by naïve readers, similar to the 67.3% found for eye-written digits from controls participants, with however, large inter-individual differences in both groups of "writers." Training with EOL was associated with a transient fatigue leading one ALS subject to drop out the study at the fifth visit. Otherwise, itching eyes was the most common adverse event (3 subjects). This study shows that, despite the impact of ALS on the motor system, most ALS participants could improve their mastering of eye-movements, so as to produce recognizable eye-written digits, although the eye-traces sometimes needed smoothing to ease digit legibility from both ALS subjects and control participants. The capability to endogenously and voluntarily generate eye-traces using EOL brings a novel way to communicate for disabled individuals, allowing creative personal and emotional expression.

Spastic paraplegia due to recessive or dominant mutations in ERLIN2 can convert to ALS.

OBJECTIVE: The aim of this study was to evaluate whether mutations in ERLIN2, known to cause SPG18, a recessive hereditary spastic paraplegia (SP) responsible for the degeneration of the upper motor neurons leading to weakness and spasticity restricted to the lower limbs, could contribute to amyotrophic lateral sclerosis (ALS), a distinct and more severe motor neuron disease (MND), in which the lower motor neurons also profusely degenerates, leading to tetraplegia, bulbar palsy, respiratory insufficiency, and ultimately the death of the patients. METHODS: Whole-exome sequencing was performed in a large cohort of 200 familial ALS and 60 sporadic ALS after a systematic screening for C9orf72 hexanucleotide repeat expansion. ERLIN2 variants identified by exome analysis were validated using Sanger analysis. Segregation of the identified variant with the disease was checked for all family members with available DNA. RESULTS: Here, we report the identification of ERLIN2 mutations in patients with a primarily SP evolving to rapid progressive ALS, leading to the death of the patients. These mutations segregated with the disease in a dominant (V168M) or recessive (D300V) manner in these families or were found in apparently sporadic cases (N125S). CONCLUSIONS: Inheritance of ERLIN2 mutations appears to be, within the MND spectrum, more complex that previously reported. These results expand the clinical phenotype of ERLIN2 mutations to a severe outcome of MND and should be considered before delivering a genetic counseling to ERLIN2-linked families.

The motor unit number index (MUNIX) profile of patients with adult spinal muscular atrophy.

OBJECTIVE: Objective of this study is the comprehensive characterisation of motor unit (MU) loss in type III and IV Spinal Muscular Atrophy (SMA) using motor unit number index (MUNIX), and evaluation of compensatory mechanisms based on MU size indices (MUSIX). METHODS: Nineteen type III and IV SMA patients and 16 gender- and age-matched healthy controls were recruited. Neuromuscular performance was evaluated by muscle strength testing and functional scales. Compound motor action potential (CMAP), MUNIX and MUSIX were studied in the abductor pollicis brevis (APB), abductor digiti minimi (ADM), deltoid, tibialis anterior and trapezius muscles. A composite MUNIX score was also calculated. RESULTS: SMA patients exhibited significantly reduced MUNIX values (p < 0.05) in all muscles, while MUSIX was increased, suggesting active re-innervation. Significant correlations were identified between MUNIX/MUSIX and muscle strength. Similarly, composite MUNIX scores correlated with disability scores. Interestingly, in SMA patients MUNIX was much lower in the ADM than in the ABP, a pattern which is distinctly different from that observed in Amyotrophic Lateral Sclerosis. CONCLUSIONS: MUNIX is a sensitive measure of MU loss in adult forms of SMA and correlates with disability. SIGNIFICANCE: MUNIX evaluation is a promising candidate biomarker for longitudinal studies and pharmacological trials in adult SMA patients.

Multicenter evaluation of neurofilaments in early symptom onset amyotrophic lateral sclerosis.

OBJECTIVE: To examine neurofilament (Nf) concentrations according to symptom onset and clinical diagnostic certainty categories of amyotrophic lateral sclerosis (ALS). METHODS: We measured Nf light chain (NfL) and phosphorylated Nf heavy chain (pNfH) CSF and NfL serum levels in patients with ALS with first symptom onset ≤6 months (n = 54) or >6 months (n = 135) from sampling, and patients with other neurologic diseases, differential diagnoses of a motor neuron disease (MND mimics), and other MND variants to determine the diagnostic accuracy in patients with ALS with early symptom onset. Samples were received multicentric and analyzed by ELISA and Simoa platform and related to other clinical measures. RESULTS: NfL and pNfH in CSF and NfL in serum were increased in early and later symptomatic phase ALS (p < 0.0001). CSF and serum NfL and CSF pNfH discriminated patients with ALS with early symptom onset from those with other neurologic diseases and MND mimics with high sensitivity (94%, 88%, 98%, and 89%, 100%, 78%) and specificity (86%, 92%, 91%, and 94%, 90%, 98%) and did not vary between clinical diagnostic categories of ALS in the early symptomatic phase group. Baseline NfL and pNfH levels were not significantly different in patients with ALS with clinical progression to definite or probable ALS at follow-up. CONCLUSION: The measurement of Nf has potential to enhance diagnostic accuracy of ALS in those presenting soon after symptom onset, and is measurable across multiple centers. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that CSF and serum Nf concentrations discriminate ALS with early symptom onset from other neurologic diseases.