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OBJECTIVE: Amyotrophic lateral sclerosis (ALS) is a multi-system disorder characterized primarily by motor neuron degeneration, but may be accompanied by cognitive dysfunction. Statistically appropriate criteria for establishing cognitive impairment (CI) in ALS are lacking. We evaluate quantile regression (QR), that accounts for age and education, relative to a traditional 2 standard deviation (SD) cut-off for defining CI. METHODS: QR of cross-sectional data from a multi-center North American Control (NAC) cohort of 269 healthy adults was used to model the 5(th) percentile of cognitive scores on the Edinburgh Cognitive and Behavioral ALS Screen (ECAS). The QR approach was compared to traditional 2 SD cut-off approach using the same NAC cohort (2SD-NAC) and to existing UK-based normative data derived using the 2SD approach (2SD-UK) to assess the impact of cohort selection and statistical model in identifying CI in 182 ALS patients. RESULTS: QR-NAC models revealed that age and education impact cognitive performance on the ECAS. Based on QR-NAC normative cutoffs, the frequency of CI in the 182 PENN ALS patients was 15.9% for ALS Specific, 12.6% for ALS Non-Specific and 15.4% for ECAS Total. This frequency of CI is substantially more conservative in comparison to the 2SD-UK (20.3%−34.6%) and modestly more conservative to the 2SD-NAC (14.3%−16.5%) approaches for estimating CI. CONCLUSIONS: The choice of normative cohort has a substantial impact and choice of statistical method a modest impact on defining CI in ALS. This report establishes normative ECAS thresholds to identify whether ALS patients in the North American population have CI.

Refereed/Peer-reviewed Background and purpose: The aim was to evaluate urinary neopterin, a marker of pro-inflammatory state, as a potential biomarker of disease prognosis and progression in amyotrophic lateral sclerosis (ALS); and to compare its utility to urinary neurotrophin receptor p75 extracellular domain (p75ECD). Methods: This was an observational study including 21 healthy controls and 46 people with ALS, 29 of whom were sampled longitudinally. Neopterin and p75ECD were measured using enzyme-linked immunoassays. Baseline and longitudinal changes in clinical measures, neopterin and urinary p75ECD were examined, and prognostic utility was explored by survival analysis. ResultsAt baseline, urinary neopterin was higher in ALS compared to controls (181.7 ± 78.9 μmol/mol creatinine vs. 120.4 ± 60.8 μmol/mol creatinine, p = 0.002, Welch's t test) and correlated with the Revised ALS Functional Rating Scale (r = −0.36, p = 0.01). Combining previously published urinary p75ECD results from 22 ALS patients with a further 24 ALS patients, baseline urinary p75ECD was also higher compared to healthy controls (6.0 ± 2.7 vs. 3.2 ± 1.0 ng/mg creatinine, p < 0.0001) and correlated with the Revised ALS Functional Rating Scale (r = −0.36, p = 0.01). Urinary neopterin and p75ECD correlated with each other at baseline (r = 0.38, p = 0.009). In longitudinal analysis, urinary neopterin increased on average (±SE) by 6.8 ± 1.1 µmol/mol creatinine per month (p < 0.0001) and p75ECD by 0.19 ± 0.02 ng/mg creatinine per month (p < 0.0001) from diagnosis in 29 ALS patients. Conclusion: Urinary neopterin holds promise as marker of disease progression in ALS and is worthy of future evaluation for its potential to predict response to anti-inflammatory therapies.

Interest in amyotrophic lateral sclerosis (ALS) biomarkers has grown exponentially over the course of the last 25 years, with great hope that they might serve as tools to facilitate the development of meaningful therapies for this otherwise inexorably progressive and invariably fatal disease. Effective use of biomarkers, however, requires an understanding of what it means for them to be ‘fit-for-purpose’ as well as an appreciation of the nuances of the clinical context(s) in which they will be applied. Neurofilament light chain (NfL) has emerged as a leading candidate with enormous potential to aid ALS therapy development; it is, however, also profoundly misunderstood. Within the conceptual framework of the BEST (Biomarkers, EndpointS, and other Tools) Resource, developed by the National Institutes of Health and the Food and Drug Administration in the USA, we consider the evidence supporting the use of NfL for a variety of purposes in different clinical contexts. We conclude that: (i) it may serve as a susceptibility/risk biomarker in populations at elevated risk for ALS; (ii) it has value as a prognostic biomarker when measured early in the course of established disease, empowering stratification or dynamic randomization to amplify the signal-to-noise ratio of promising therapeutics; and (iii) there is sufficient evidence to support the use of a reduction in NfL in response to an experimental therapeutic as a pharmacodynamic biomarker that may aid in phase 2 trial go/no-go decisions. Moreover, the basis for expecting that a reduction in NfL is a reasonably likely surrogate end-point (i.e. reasonably likely to predict clinical benefit—which may be more than simply survival) is nuanced, and depends on when in the course of disease the experimental therapeutic is administered.

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized primarily by progressive loss of motor neurons. Although ALS occurs worldwide and the frequency and spectrum of identifiable genetic causes of disease varies across populations, very few studies have included African subjects. In addition to a hexanucleotide repeat expansion (RE) in C9orf72, the most common genetic cause of ALS in Europeans, REs in ATXN2, NIPA1 and ATXN1 have shown variable associations with ALS in Europeans. Intermediate range expansions in some of these genes (e.g. ATXN2) have been reported as potential risk factors, or phenotypic modifiers, of ALS. Pathogenic expansions in NOP56 cause spinocerebellar ataxia-36, which can present with prominent motor neuron degeneration. Here we compare REs in these genes in a cohort of Africans with ALS and population controls using whole genome sequencing data. Targeting genotyping of short tandem repeats at known loci within ATXN2, NIPA1, ATXN1 and NOP56 was performed using ExpansionHunter software in 105 Southern African (SA) patients with ALS. African population controls were from an in-house SA population control database (n = 25), the SA Human Genome Program (n = 24), the Simons Genome Diversity Project (n = 39) and the Illumina Polaris Diversity Cohort (IPDC) dataset (n = 50). We found intermediate RE alleles in ATXN2 (27–33 repeats) and ATXN1 (33–35 repeats), and NIPA1 long alleles (≥8 repeats) were rare in Africans, and not associated with ALS (p > 0.17). NOP56 showed no expanded alleles in either ALS or controls. We also compared the differences in allele distributions between the African and n = 50 European controls (from the IPDC). There was a statistical significant difference in the distribution of the REs in the ATXN1 between African and European controls (Chi-test p 8) in Europeans vs. Africans (Fisher’s p = 0.016). The distribution of RE alleles in ATXN2 and NOP56 were similar amongst African and European controls. In conclusion, repeat expansions in ATXN2, NIPA1 and ATXN1, which showed associations with ALS in Europeans, were not replicated in Southern Africans with ALS., Highlights • No associations with ATXN2, ATXN1, NIPA1 expansion mutations, and ALS in Africans. • Repeat expansion allele distribution in ATXN1 and NIPA1 were different in Africans compared with European populations. • ALS cases with diverse genetic ancestry should included in ALS gene discovery studies.

As novel therapeutic interventions are being developed and tested in the amyotrophic lateral sclerosis (ALS) population, there is a need to better understand the symptoms and issues that have the greatest impact on the lives of individuals with ALS. We aimed to determine the frequency and relative importance of symptoms experienced by adults in a national ALS sample and to identify factors that are associated with the greatest disease burden in this population.We conducted 15 qualitative interviews of individuals with varied ALS phenotypes and analyzed 732 quotes regarding the symptomatic disease burden of ALS between August 2018 and March 2019. We subsequently conducted a national, cross-sectional study of 497 participants with ALS and ALS variants through the Centers for Disease Control and Prevention's (CDC) National ALS Registry between July 2019 and December 2019. Participants reported on the prevalence and relative importance of 189 symptomatic questions representing 17 symptomatic themes that were previously identified through qualitative interviews. Analysis was performed to determine how age, sex, education, employment, time since onset of symptoms, location of symptom onset, feeding tube status, breathing status and speech status relate to symptom and symptomatic theme prevalence.Symptomatic themes with the highest prevalence in our sample were an inability to do activities (93.8%), fatigue (92.6%), problems with hands or fingers (87.7%), limitations with mobility or walking (86.7%), and a decreased performance in social situations (85.7%). Participants identified inability to do activities and limitations with mobility or walking as having the greatest overall effect on their lives.Individuals with ALS experience a variety of symptoms that affect their lives. The prevalence and importance of these symptoms differ among the ALS population. The most prevalent and important symptoms offer potential targets for improvements in future therapeutic interventions.Research funding was provided by ALS Association.

Objective To evaluate the CSF levels of chitinase proteins during the presymptomatic and early symptomatic phases of amyotrophic lateral sclerosis (ALS). Methods CSF samples were obtained from 16 controls, 55 individuals at‐risk for ALS (including 18 carrying a mutation in C9ORF72 , 33 in SOD1 ), 12 ALS patients, and 7 phenoconverters (individuals diagnosed with ALS during follow‐up). At‐risk individuals and phenoconverters were enrolled through the Pre‐fALS study, which includes individuals carrying an ALS‐associated gene mutation without disease manifestations at initial assessment. Longitudinal CSF collections, where possible, took place every 3‐12 months for ALS patients and every 1‐2 years for others. CSF levels of chitotriosidase 1 (CHIT1), chitinase‐3‐like protein 1 (CHI3L1, YKL‐40) and chitinase‐3‐like protein 2 (CHI3L2, YKL‐39) were measured by ELISA, along with CHIT1 activity. Longitudinal changes in at‐risk individuals and phenoconverters were fitted to linear mixed effects models. Results Slowly rising levels of CHIT1 were observed over time in the at‐risk individuals (slope 0.059 log10[CHIT1] per year, P < 0.001). Among phenoconverters, CHIT1 levels and activity rose more sharply (0.403 log10[CHIT1] per year, P = 0.005; 0.260 log10[CHIT1 activity] per year, P = 0.007). Individual levels of both CHI3L1 and CHI3L2 remained relatively stable over time in all participant groups. Interpretation The CHIT1 neuroinflammatory response is a feature of the late presymptomatic to early symptomatic phases of ALS. This study does not suggest a long prodrome of upregulated glial activity in ALS pathogenesis, but strengthens the place of CHIT1 as part of a panel of biomarkers to objectively assess the impact of immune‐modulatory therapeutic interventions in ALS.

Significant progress has been made in understanding the pre-symptomatic phase of amyotrophic lateral sclerosis. While much is still unknown, advances in other neurodegenerative diseases offer valuable insights. Indeed, it is increasingly clear that the well-recognized clinical syndromes of Alzheimer’s disease, Parkinson’s disease, Huntington’s disease, spinal muscular atrophy and frontotemporal dementia are also each preceded by a pre-symptomatic or prodromal period of varying duration, during which the underlying disease process unfolds, with associated compensatory changes and loss of inherent system redundancy. Key insights from these diseases highlight opportunities for discovery in amyotrophic lateral sclerosis. The development of biomarkers reflecting amyloid and tau has led to a shift in defining Alzheimer’s disease based on inferred underlying histopathology. Parkinson’s disease is unique among neurodegenerative diseases in the number and diversity of non-genetic biomarkers of pre-symptomatic disease, most notably REM sleep behaviour disorder. Huntington’s disease benefits from an ability to predict the likely timing of clinically manifest disease based on age and CAG-repeat length alongside reliable neuroimaging markers of atrophy. Spinal muscular atrophy clinical trials have highlighted the transformational value of early therapeutic intervention, and studies in frontotemporal dementia illustrate the differential role of biomarkers based on genotype. Similar advances in amyotrophic lateral sclerosis would transform our understanding of key events in pathogenesis, thereby dramatically accelerating progress towards disease prevention. Deciphering the biology of pre-symptomatic amyotrophic lateral sclerosis relies on a clear conceptual framework for defining the earliest stages of disease. Clinically manifest amyotrophic lateral sclerosis may emerge abruptly, especially among those who harbour genetic mutations associated with rapidly progressive amyotrophic lateral sclerosis. However, the disease may also evolve more gradually, revealing a prodromal period of mild motor impairment preceding phenoconversion to clinically manifest disease. Similarly, cognitive and behavioural impairment, when present, may emerge gradually, evolving through a prodromal period of mild cognitive impairment or mild behavioural impairment before progression to amyotrophic lateral sclerosis. Biomarkers are critically important to studying pre-symptomatic amyotrophic lateral sclerosis and essential to efforts to intervene therapeutically before clinically manifest disease emerges. The use of non-genetic biomarkers, however, presents challenges related to counselling, informed consent, communication of results and limited protections afforded by existing legislation. Experiences from pre-symptomatic genetic testing and counselling, and the legal protections against discrimination based on genetic data, may serve as a guide. Building on what we have learned—more broadly from other pre-symptomatic neurodegenerative diseases and specifically from amyotrophic lateral sclerosis gene mutation carriers—we present a road map to early intervention, and perhaps even disease prevention, for all forms of amyotrophic lateral sclerosis.

Despite extensive research, amyotrophic lateral sclerosis (ALS) remains a progressive and invariably fatal neurodegenerative disease. Limited knowledge of the underlying causes of ALS has made it difficult to target upstream biological mechanisms of disease, and therapeutic interventions are usually administered relatively late in the course of disease. Genetic forms of ALS offer a unique opportunity for therapeutic development, as genetic associations may reveal potential insights into disease etiology. Genetic ALS may also be amenable to investigating earlier intervention given the possibility of identifying clinically presymptomatic, at-risk individuals with causative genetic variants. There is increasing evidence for a presymptomatic phase of ALS, with biomarker data from the Pre-Symptomatic Familial ALS (Pre-fALS) study showing that an elevation in blood neurofilament light chain (NfL) precedes phenoconversion to clinically manifest disease. Tofersen is an investigational antisense oligonucleotide designed to reduce synthesis of superoxide dismutase 1 (SOD1) protein through degradation of SOD1 mRNA. Informed by Pre-fALS and the tofersen clinical development program, the ATLAS study (NCT04856982) is designed to evaluate the impact of initiating tofersen in presymptomatic carriers of SOD1 variants associated with high or complete penetrance and rapid disease progression who also have biomarker evidence of disease activity (elevated plasma NfL). The ATLAS study will investigate whether tofersen can delay the emergence of clinically manifest ALS. To our knowledge, ATLAS is the first interventional trial in presymptomatic ALS and has the potential to yield important insights into the design and conduct of presymptomatic trials, identification, and monitoring of at-risk individuals, and future treatment paradigms in ALS. Errata: Benatar, M., Wuu, J., Andersen, P.M. et al. Correction to: Design of a Randomized, Placebo-Controlled, Phase 3 Trial of Tofersen Initiated in Clinically Presymptomatic SOD1 Variant Carriers: the ATLAS Study. Neurotherapeutics (2022). https://doi.org/10.1007/s13311-022-01286-9

Amyotrophic lateral sclerosis, when viewed as a biological entity rather than a clinical syndrome, probably evolves along a continuum, with the initial clinically silent phase eventually evolving into clinically manifest amyotrophic lateral sclerosis. Since motor neuron degeneration is incremental and cumulative over time, it stands to reason that the clinical syndrome of amyotrophic lateral sclerosis is probably preceded by a prodromal state characterized by minor motor abnormalities that are initially insufficient to permit a diagnosis of amyotrophic lateral sclerosis. This prodromal period, however, is usually missed, given the invariably long delays between symptom onset and diagnostic evaluation. The Pre-Symptomatic Familial ALS Study, a cohort study of pre-symptomatic gene mutation carriers, offers a unique opportunity to observe what is typically unseen. Here we describe the clinical characterization of 20 pre-symptomatic mutation carriers (in SOD1, FUS and C9orf72) whose phenoconversion to clinically manifest disease has been prospectively studied. In so doing, we observed a prodromal phase of mild motor impairment in 11 of 20 phenoconverters. Among the n = 12 SOD1 A4V mutation carriers, phenoconversion was characterized by abrupt onset of weakness, with a short (1-3.5 months) prodromal period observable in a small minority (n = 3); the observable prodrome invariably involved the lower motor neuron axis. By contrast, in all n = 3 SOD1 I113T mutation carriers, diffuse lower motor neuron and upper motor neuron signs evolved insidiously during a prodromal period that extended over a period of many years; prodromal manifestations eventually coalesced into a clinical syndrome that is recognizable as amyotrophic lateral sclerosis. Similarly, in all n = 3 C9orf72 hexanucleotide repeat expansion mutation carriers, focal or multifocal manifestations of disease evolved gradually over a prodromal period of 1-2 years. Clinically manifest ALS also emerged following a prodromal period of mild motor impairment, lasting >4 years and similar to 9 months, respectively, in n = 2 with other gene mutations (SOD1 L106V and FUS c.521del6). On the basis of this empirical evidence, we conclude that mild motor impairment is an observable state that precedes clinically manifest disease in three of the most common genetic forms of amyotrophic lateral sclerosis (SOD1, FUS, C9orf72), and perhaps in all genetic amyotrophic lateral sclerosis; we also propose that this might be true of non-genetic amyotrophic lateral sclerosis. As a diagnostic label, mild motor impairment provides the language to describe the indeterminate (and sometimes intermediate) transition between the unaffected state and clinically manifest amyotrophic lateral sclerosis. Recognizing mild motor impairment as a distinct clinical entity should generate fresh urgency for developing biomarkers reflecting the earliest events in the degenerative cascade, with potential to reduce the diagnostic delay and to permit earlier therapeutic intervention. Having observed ALS phenoconversion in 20 pre-symptomatic gene mutation carriers, Benatar et al. conclude that a prodromal period of mild motor impairment (MMI) precedes many (if not most) forms of ALS. They highlight the implications for reducing diagnostic delay and for early therapeutic intervention.

The electronic health record (EHR) is designed principally to support the provision and documentation of clinical care, as well as billing and insurance claims. Broad implementation of the EHR, however, also yields an opportunity to use EHR data for other purposes, including research and quality improvement. Indeed, effective use of clinical data for research purposes has been a long-standing goal of physicians who provide care for patients with ALS, but the quality and completeness of clinical data, as well as the burden of double data entry into the EHR and into a research database, have been persistent barriers. These factors provided motivation for the development of the ALS Toolkit, a set of interactive digital forms within the EHR that enable easy, consistent, and structured capture of information relevant to ALS patient care (as well as research and quality improvement) during clinical encounters. Routine use of the ALS Toolkit within the context of the CReATe Consortium's institutional review board-approved Clinical Procedures to Support Research in ALS (CAPTURE-ALS) study protocol, permits aggregation of structured ALS patient data, with the goals of empowering research and driving quality improvement. Widespread use of the ALS Toolkit through the CAPTURE-ALS protocol will help to ensure that ALS clinics become a driving force for collecting and aggregating clinical data in a way that reflects the true diversity of the populations affected by this disease, rather than the restricted subset of patients that currently participate in dedicated research studies.

Objective. To evaluate serum and cerebrospinal fluid (CSF) levels of phosphorylated neurofilament heavy (pNfH), and to compare these to levels of neurofilament light (NfL), as biomarkers of pre-symptomatic ALS. Design. The study population includes 34 controls, 79 individuals at-risk for ALS, 22 ALS patients, and 14 phenoconverters. At-risk individuals are enrolled through Pre-Symptomatic Familial ALS (Pre-fALS), a longitudinal natural history and biomarker study of individuals who are carriers of any ALS-associated gene mutation, but who demonstrate no clinical evidence of disease at the time of enrollment. pNfH and NfL in serum and CSF were quantified using established enzyme-linked immunosorbent assays. Results. There is a longitudinal increase in serum pNfH in advance of the emergence of clinically manifest ALS. A similar pattern is observed for NfL, but with the absolute levels also frequently exceeding a normative threshold. Although CSF data are more sparse, similar patterns are observed for both neurofilaments, with absolute levels exceeding a normative threshold prior to phenoconversion. In serum, these changes are observed in the 6–12 months prior to disease among SOD1 A4V mutation carriers, and as far back as 2 and 3.5 years, respectively, in individuals with a FUS c.521del6 mutation and a C9ORF72 hexanucleotide repeat expansion. Conclusions. Serum and CSF pNfH increase prior to phenoconversion. In CSF, the temporal course of these changes is similar to NfL. In serum, however, pNfH is less sensitive to pre-symptomatic disease than NfL. The duration of pre-symptomatic disease, as defined by changes in neurofilaments, may vary depending on underlying genotype.

Numerous reports have suggested that infectious agents could play a role in neurodegenerative diseases, but specific etiological agents have not been convincingly demonstrated. To search for candidate agents in an unbiased fashion, we have developed a bioinformatic pipeline that identifies microbial sequences in mammalian RNA-seq data, including sequences with no significant nucleotide similarity hits in GenBank. Effectiveness of the pipeline was tested using publicly available RNA-seq data and in a reconstruction experiment using synthetic data. We then applied this pipeline to a novel RNA-seq dataset generated from a cohort of 120 samples from amyotrophic lateral sclerosis patients and controls, and identified sequences corresponding to known bacteria and viruses, as well as novel virus-like sequences. The presence of these novel virus-like sequences, which were identified in subsets of both patients and controls, were confirmed by quantitative RT-PCR. We believe this pipeline will be a useful tool for the identification of potential etiological agents in the many RNA-seq datasets currently being generated.

Amyotrophic lateral sclerosis (ALS) is a multi‐system disease characterized primarily by progressive muscle weakness. Cognitive dysfunction is commonly observed in patients; however, factors influencing risk for cognitive dysfunction remain elusive. Using sparse canonical correlation analysis (sCCA), an unsupervised machine‐learning technique, we observed that single nucleotide polymorphisms collectively associate with baseline cognitive performance in a large ALS patient cohort (N = 327) from the multicenter Clinical Research in ALS and Related Disorders for Therapeutic Development (CReATe) Consortium. We demonstrate that a polygenic risk score derived using sCCA relates to longitudinal cognitive decline in the same cohort and also to in vivo cortical thinning in the orbital frontal cortex, anterior cingulate cortex, lateral temporal cortex, premotor cortex, and hippocampus (N = 90) as well as post‐mortem motor cortical neuronal loss (N = 87) in independent ALS cohorts from the University of Pennsylvania Integrated Neurodegenerative Disease Biobank. Our findings suggest that common genetic polymorphisms may exert a polygenic contribution to the risk of cortical disease vulnerability and cognitive dysfunction in ALS., Single nucleotide polymorphisms (SNPs) previously identified through genome‐wide association studies as risk factors for amyotrophic lateral sclerosis (ALS) and/or frontotemporal dementia (FTD) further associate in a polygenic manner with risk for cognitive dysfunction in ALS and related disorders.

ImportanceAmyotrophic lateral sclerosis (ALS) is a multi-system disorder characterized primarily by motor neuron degeneration, but may be accompanied by cognitive dysfunction. Statistically appropriate criteria for establishing cognitive impairment (CI) in ALS are lacking.ObjectiveDefine thresholds for CI in ALS using quantile regression (QR) that accounts for age and education in a North American (NAmer) cohort.DesignQR of cross-sectional data from a multi-center NAmer cohort of healthy adults was used to model the 5th percentile of cognitive scores on the Edinburgh Cognitive and Behavioral ALS Screen (ECAS). The QR approach was compared to a traditional 2 standard deviation (SD) cut-off approach using the same NAmer cohort (2SD-NAmer) and to existing UK-based normative data derived using the 2SD approach (2SD-UK) to assess the impact of cohort selection and statistical model in identifying CI ALS patients.Participants269 healthy adults from NAmer, recruited by the University of Pennsylvania (PENN; N=82), the University of Miami through the CRiALS study (CRiALS; N=40), and the Canadian ALS Neuroimaging Consortium (CALSNIC; N=147) were included to establish ECAS thresholds for defining CI. We then evaluated the frequency of CI in 182 ALS patients from PENN.Main OutcomesWe defined two new sets of normative thresholds, based on NAmer heathy adult performance, for each ECAS domain score and the composite scores using QR and 2SD statistical approaches. We then applied the 2SD-NAmer and QR-NAmer, as well as the previously established and widely-used 2SD-UK, thresholds to evaluate the frequency of CI in ALS patients.ResultsQR-NAmer models revealed that increased age and reduced educational attainment negatively impact cognitive performance on the ECAS. Based on the QR-NAmer normative cutoffs, the prevalence of CI in the 182 PENN ALS patients was 15.9% for ECAS ALS-Specific and 15.4% for ECAS Total. These estimates are more conservative than estimates ranging from 15.4%-34.6% impaired based on 2SD approaches.Conclusions and RelevanceThis report establishes normative thresholds for using ECAS to identify whether ALS patients in the NAmer population have CI. The choice of statistical method and normative cohort has a substantial impact on defining CI in ALS.Key PointsQuestionHow to define cognitive impairment (CI) in amyotrophic lateral sclerosis (ALS) using the Edinburgh Cognitive and Behavioral ALS Screen (ECAS)?FindingsAge- and education-adjusted quantile regression (QR) yields thresholds for defining CI that differ meaningfully from those derived from parametric methods without age- and education-adjustment. Thresholds also differ between UK and North American cohorts. Applying our North American-based QR norms to an American ALS cohort at a single center identified CI based on ECAS performance in ∼16% patients, compared to 15.4%-34.6% patients using other approaches.MeaningThe choice of statistical method and normative cohort has a substantial impact on defining CI in ALS.

An inherent challenge to clinical trials that aim to test the efficacy of experimental therapeutics for patients with amyotrophic lateral sclerosis (ALS) is the relative rarity of the disease. A promising solution to this problem is a multi-center approach that ideally includes sites distributed across a broad geographic area. In support of such an approach, the European E-RARE program and the United States National Institutes of Health (NIH) partnered to support the investigator-initiated ROCK-ALS trial (Eudra-CT-Nr.: 2017-003676-31, NCT03792490) as a multi-national collaboration between centers in Europe and North America that is led by a European investigator. During the set-up of this international trial, however, a number of unanticipated legal, administrative, and financial complexities emerged that required significant adaptation of the proposed trial scheme. Here, we report our experience navigating these obstacles and describe the potential solutions that we explored. Our experience may inform future efforts to implement multi-national investigator-initiated trials that involve both European and United States centers.

Objectives The neural activity of the primary motor cortex is variably synchronised with contralateral peripheral electromyographic signals, which is thought to facilitate long-range communication through the motor system. Such corticomuscular coherence (CMC) is typically observed in the beta-band (15–30 Hz) range during steady force production. We aimed to measure pathological alteration to CMC resulting from ALS. Methods CMC was appraised during a forearm grip task in 17 ALS patients contrasted against age-matched healthy controls. An exploratory comparison with a group of asymptomatic ALS gene carriers and neuropathy disease mimics was also undertaken. Neural signals were acquired by whole-head magnetoencephalography and localised via structural MRI to the motor cortices. Results During light voluntary muscular contraction, beta-band CMC was significantly reduced in ALS patients compared to healthy controls. Propagation of motoric beta rhythms across the cortical hemispheres was also shown to be impaired in ALS patients. CMC was preserved in the asymptomatic gene carrier and did not distinguish ALS patients from neuropathy mimics. Conclusion Functional connectivity metrics reveal an ALS-related decrease in both corticomuscular and interhemispheric communication during bilateral grip force production. Significance MEG-derived beta oscillation coupling may be a potential biomarker of motor system dysfunction in ALS, against which to measure future therapeutic efficacy.

Objective: To evaluate neurofilament light (NfL) as a biomarker of the presymptomatic phase of amyotrophic lateral sclerosis (ALS).Methods: The study population includes 84 individuals at risk for ...

Background and ObjectivesTo perform the first screen of 44 amyotrophic lateral sclerosis (ALS) genes in a cohort of African genetic ancestry individuals with ALS using whole-genome sequencing (WGS) data.MethodsOne hundred three consecutive cases with probable/definite ALS (using the revised El Escorial criteria), and self-categorized as African genetic ancestry, underwent WGS using various Illumina platforms. As population controls, 238 samples from various African WGS data sets were included. Our analysis was restricted to 44 ALS genes, which were curated for rare sequence variants and classified according to the American College of Medical Genetics guidelines as likely benign, uncertain significance, likely pathogenic, or pathogenic variants.ResultsThirteen percent of 103 ALS cases harbored pathogenic variants; 5 different SOD1 variants (N87S, G94D, I114T, L145S, and L145F) in 5 individuals (5%, 1 familial case), pathogenic C9orf72 repeat expansions in 7 individuals (7%, 1 familial case) and a likely pathogenic ANXA11 (G38R) variant in 1 individual. Thirty individuals (29%) harbored ≥1 variant of uncertain significance; 10 of these variants had limited pathogenic evidence, although this was insufficient to permit confident classification as pathogenic.DiscussionOur findings show that known ALS genes can be expected to identify a genetic cause of disease in >11% of sporadic ALS cases of African genetic ancestry. Similar to European cohorts, the 2 most frequent genes harboring pathogenic variants in this population group are C9orf72 and SOD1.

As potential treatments for C9ORF72-associated amyotrophic lateral sclerosis (c9ALS) approach clinical trials, the identification of prognostic biomarkers for c9ALS becomes a priority. We show that levels of phosphorylated neurofilament heavy chain (pNFH) in cerebrospinal fluid (CSF) predict disease status and survival in c9ALS patients, and are largely stable over time. Moreover, c9ALS patients exhibit higher pNFH levels, more rapid disease progression, and shorter survival after disease onset than ALS patients without C9ORF72 expansions. These data support the use of CSF pNFH as a prognostic biomarker for clinical trials, which will increase the likelihood of successfully developing a treatment for c9ALS. Ann Neurol 2017;82:139-146.

Objective:To evaluate urinary neurotrophin receptor p75 extracellular domain (p75ECD) levels as disease progression and prognostic biomarkers in amyotrophic lateral sclerosis (ALS).Methods:The population in this study comprised 45 healthy controls and 54 people with ALS, 31 of whom were sampled longitudinally. Urinary p75ECD was measured using an enzyme-linked immunoassay and validation included intra-assay and inter-assay coefficients of variation, effect of circadian rhythm, and stability over time at room temperature, 4°C, and repeated freeze-thaw cycles. Longitudinal changes in urinary p75ECD were examined by mixed model analysis, and the prognostic value of baseline p75ECD was explored by survival analysis.Results:Confirming our previous findings, p75ECD was higher in patients with ALS (5.6 ± 2.2 ng/mg creatinine) compared to controls (3.6 ± 1.4 ng/mg creatinine, p < 0.0001). Assay reproducibility was high, with p75ECD showing stability across repeated freeze-thaw cycles, at room temperature and 4°C for 2 days, and no diurnal variation. Urinary p75ECD correlated with the revised ALS Functional Rating Scale at first evaluation (r = −0.44, p = 0.008) and across all study visits (r = −0.36, p < 0.0001). p75ECD also increased as disease progressed at an average rate of 0.19 ng/mg creatinine per month (p < 0.0001). In multivariate prognostic analysis, bulbar onset (hazard ratio [HR] 3.0, p = 0.0035), rate of disease progression from onset to baseline (HR 4.4, p < 0.0001), and baseline p75ECD (HR 1.3, p = 0.0004) were predictors of survival.Conclusions:The assay for urinary p75ECD is analytically robust and shows promise as an ALS biomarker with prognostic, disease progression, and potential pharmacodynamic application. Baseline urinary p75ECD provides prognostic information and is currently the only biological fluid–based biomarker of disease progression.

ObjectiveTo identify preferred neurofilament assays and clinically validate serum neurofilament light (NfL) and phosphorylated neurofilament heavy (pNfH) as prognostic and potential pharmacodynamic biomarkers relevant to amyotrophic lateral sclerosis (ALS) therapy development.MethodsIn this prospective, multicenter, longitudinal observational study of patients with ALS (n = 229), primary lateral sclerosis (n = 20), and progressive muscular atrophy (n = 11), biological specimens were collected, processed, and stored according to strict standard operating procedures (SOPs). Neurofilament assays were performed in a blinded manner by independent contract research organizations.ResultsFor serum NfL and pNfH measured using the Simoa assay, there were no missing data (i.e., technical replicates below the lower limit of detection were not encountered). For the Iron Horse and Euroimmun pNfH assays, such missingness was encountered in ∼4% and ∼10% of serum samples, respectively. Mean coefficients of variation for NfL in serum and CSF were both ∼3%. Mean coefficients of variation for pNfH in serum and CSF were ∼4%–5% and ∼2%–3%, respectively, in all assays. Baseline serum NfL concentration, but not pNfH, predicted the future Revised ALS Functional Rating Scale (ALSFRS-R) slope and survival. Incorporation of baseline serum NfL into mixed effects models of ALSFRS-R slopes yields an estimated sample size saving of ∼8%. Depending on the method used to estimate effect size, use of serum NfL (and perhaps pNfH) as pharmacodynamic biomarkers, instead of the ALSFRS-R slope, yields significantly larger sample size savings.ConclusionsSerum NfL may be considered a clinically validated prognostic biomarker for ALS. Serum NfL (and perhaps pNfH), quantified using the Simoa assay, has potential utility as a pharmacodynamic biomarker of treatment effect.

Amyotrophic lateral sclerosis (ALS) is a multi-system disease characterized primarily by progressive muscle weakness. Cognitive dysfunction is commonly observed in patients, however factors influencing risk for cognitive dysfunction remain elusive. Using sparse canonical correlation analysis (sCCA), an unsupervised machine-learning technique, we observed that single nucleotide polymorphisms collectively associate with baseline cognitive performance in a large ALS patient cohort (N=327) from the multicenter Clinical Research in ALS and Related Disorders for Therapeutic Development (CReATe) Consortium. We demonstrate that a polygenic risk score derived using sCCA relates to longitudinal cognitive decline in the same cohort, and also to in vivo cortical thinning in the orbital frontal cortex, anterior cingulate cortex, lateral temporal cortex, premotor cortex, and hippocampus (N=90) as well as post mortem motor cortical neuronal loss (N=87) in independent ALS cohorts from the University of Pennsylvania Integrated Neurodegenerative Disease Biobank. Our findings suggest that common genetic polymorphisms may exert a polygenic contribution to the risk of cortical disease vulnerability and cognitive dysfunction in ALS.

To discover novel genes underlying amyotrophic lateral sclerosis (ALS), we aggregated exomes from 3,864 cases and 7,839 ancestry-matched controls. We observed a significant excess of rare protein-truncating variants among ALS cases, and these variants were concentrated in constrained genes. Through gene level analyses, we replicated known ALS genes including SOD1, NEK1 and FUS. We also observed multiple distinct protein-truncating variants in a highly constrained gene, DNAJC7. The signal in DNAJC7 exceeded genome-wide significance, and immunoblotting assays showed depletion of DNAJC7 protein in fibroblasts in a patient with ALS carrying the p.Arg156Ter variant. DNAJC7 encodes a member of the heat-shock protein family, HSP40, which, along with HSP70 proteins, facilitates protein homeostasis, including folding of newly synthesized polypeptides and clearance of degraded proteins. When these processes are not regulated, misfolding and accumulation of aberrant proteins can occur and lead to protein aggregation, which is a pathological hallmark of neurodegeneration. Our results highlight DNAJC7 as a novel gene for ALS.

Background Receptive and expressive vocabulary in adult and adolescent males with fragile X syndrome (FXS) have been shown as significantly lower than their chronological age; however, receptive vocabulary has been considered a strength relative to mental age. This has not been formally examined, however, and data are needed to compare receptive vocabulary with other language skills and with mental age in individuals with FXS. This is especially important as vocabulary measures are sometimes used as a proxy to estimate language ability. Methods This preliminary study examined receptive vocabulary, global language, and cognitive skills in 42 adults (33 males and 9 females) with FXS as a portion of the baseline evaluation prior to randomization in a clinical trial of ampakine CX516. The battery of standardized tests addressed receptive vocabulary with the Peabody Picture Vocabulary Test, Third Edition (PPVT-III), receptive and expressive language (termed henceforth as global language) via the Preschool Language Scale, Fourth Edition or the Clinical Evaluation of Language Fundamentals, Third Edition, and non-verbal cognition via the Stanford-Binet Intelligence Scales, Fourth Edition (SB-IV). Results Results showed (1) significantly higher receptive vocabulary than global language, (2) significantly better receptive vocabulary than non-verbal cognition, (3) equivalent non-verbal cognition and global language, and (4) severity of autism symptomatology was not correlated to receptive vocabulary or global language once non-verbal cognition was removed as factor. The scores from the PPVT-III did not represent the global language skills in our sample of adults with FXS. Conclusions Findings from this investigation strongly suggest that the PPVT-III should not be used as a screening tool for language levels or cognitive function in clinical studies since the scores from the PPVT-III were not representative of global language or non-verbal cognitive skills in adults with intellectual disabilities. This finding is critical in order to understand how to evaluate, as well as to treat, language in individuals with FXS. Development of efficient and appropriate tools to measure language, cognition, and behavior in individuals with FXS is essential.

ObjectiveIdentify preferred neurofilament assays, and clinically validate serum NfL and pNfH as prognostic and potential pharmacodynamic biomarkers relevant to ALS therapy development.MethodsProspective, multi-center, longitudinal observational study of patients with ALS (n=229), primary lateral sclerosis (PLS, n=20) and progressive muscular atrophy (PMA, n=11). Biological specimens were collected, processed and stored according to strict standard operating procedures (SOPs) 1. Neurofilament assays were performed in a blinded manner by independent contract research organizations (CROs).ResultsFor serum NfL and pNfH measured using the Simoa assay, missing data (i.e. both technical replicates below the lower limit of detection (LLD) was not encountered. For the Iron Horse and Euroimmun pNfH assays, such missingness was encountered in ∼4% and ∼10% of serum samples respectively. Mean coefficients of variation (CVs) for pNfH in serum and CSF were ∼4-5% and ∼2-3% respectively in all assays. Baseline NfL concentration, but not pNfH, predicted the future ALSFRS-R slope and survival.Incorporation of baseline serum NfL into mixed effects models of ALSFRS-R slopes yields an estimated sample size saving of ∼8%. Depending on the method used to estimate effect size, use of serum NfL (and perhaps pNfH) as pharmacodynamic biomarkers, instead of the ALSFRS-R slope, yields significantly larger sample size savings.ConclusionsSerum NfL may be considered a clinically validated prognostic biomarker for ALS. Serum NfL (and perhaps pNfH), quantified using the Simoa assay, have potential utility as pharmacodynamic biomarkers of treatment effect.

The discovery of novel biomarkers has emerged as a critical need for therapeutic development in amyotrophic lateral sclerosis (ALS). For some subsets of ALS, such as the genetic superoxide dismutase 1 (SOD1) form, exciting new treatment strategies, such as antisense oligonucleotide–mediated (ASO-mediated) SOD1 silencing, are being tested in clinical trials, so the identification of pharmacodynamic biomarkers for therapeutic monitoring is essential. We identify increased levels of a 7–amino acid endogenous peptide of SOD1 in cerebrospinal fluid (CSF) of human SOD1 mutation carriers but not in other neurological cases or nondiseased controls. Levels of peptide elevation vary based on the specific SOD1 mutation (ranging from 1.1-fold greater than control in D90A to nearly 30-fold greater in V148G) and correlate with previously published measurements of SOD1 stability. Using a mass spectrometry–based method (liquid chromatography–mass spectrometry), we quantified peptides in both extracellular samples (CSF) and intracellular samples (spinal cord from rat) to demonstrate that the peptide distinguishes mutation-specific differences in intracellular SOD1 degradation. Furthermore, 80% and 63% reductions of the peptide were measured in SOD1(G93A) and SOD1(H46R) rat CSF samples, respectively, following treatment with ASO, with an improved correlation to mRNA levels in spinal cords compared with the ELISA measuring intact SOD1 protein. These data demonstrate the potential of this peptide as a pharmacodynamic biomarker.

Successful treatment of neurodegenerative disease may hinge on early therapeutic intervention. This requires an understanding of early/pre-symptomatic disease, a need that is underscored by advances in antisense oligonucleotide, and viral-vector-based gene therapies. In amyotrophic lateral sclerosis (ALS), the study of pre-symptomatic disease requires a cohesive conceptual framework for describing this phase of disease. Informed by the literature in other neurodegenerative diseases and extensive personal experience, a model is proposed that distinguishes ALS as a clinical syndrome from ALS as a disease, and characterizes pre-symptomatic ALS as having two identifiable stages: pre-manifest and prodromal. The unique and critical importance of biomarker development is articulated and an operational definition of phenoconversion is provided. It is hoped that this framework will accelerate collective efforts to study pre-symptomatic ALS, and aid in the design and implementation of an early intervention- or disease-prevention trial.

Copyright © 2016 World Federation of Neurology on behalf of the Research Group on Motor Neuron Diseases, A large GGGGCC-repeat expansion mutation (HREM) in C9orf72 is the most common known cause of ALS and FTD in European populations. Sequence variations immediately downstream of the HREM region have previously been observed and have been suggested to be one reason for difficulties in interpreting RP-PCR data. Our objective was to determine the properties of these sequence variations with regard to prevalence, the range of variation, and effect on disease prognosis. We screened a multi-national cohort (n = 6981) for the HREM and samples with deviant RP-PCR curves were identified. The deviant samples were subsequently sequenced to determine sequence alteration. Our results show that in the USA and European cohorts (n = 6508) 10.7% carried the HREM and 3% had a sequence variant, while no HREM or sequence variants were observed in the Japanese cohort (n = 473). Sequence variations were more common on HREM alleles; however, certain population specific variants were associated with a non-expanded allele.In conclusion, we identified 38 different sequence variants, most located within the first 50 bp downstream of the HREM region. Furthermore, the presence of an HREM was found to be coupled to a lower age of onset and a shorter disease survival, while sequence variation did not have any correlation with these parameters.

SUMMARYTo discover novel genetic risk factors underlying amyotrophic lateral sclerosis (ALS), we aggregated exomes from 3,864 cases and 7,839 ancestry matched controls. We observed a significant excess of ultra-rare and rare protein-truncating variants (PTV) among ALS cases, which was primarily concentrated in constrained genes; however, a significant enrichment in PTVs does persist in the remaining exome. Through gene level analyses, known ALS genes, SOD1, NEK1, and FUS, were the most strongly associated with disease status. We also observed suggestive statistical evidence for multiple novel genes including DNAJC7, which is a highly constrained gene and a member of the heat shock protein family (HSP40). HSP40 proteins, along with HSP70 proteins, facilitate protein homeostasis, such as folding of newly synthesized polypeptides, and clearance of degraded proteins. When these processes are not regulated, misfolding and accumulation of degraded proteins can occur leading to aberrant protein aggregation, one of the pathological hallmarks of neurodegeneration.

ObjectiveWe sought to assess cortical function in amyotrophic lateral sclerosis (ALS) using noninvasive neural signal recording.MethodsResting-state magnetoencephalography was used to measure power fluctuations in neuronal oscillations from distributed cortical parcels in 24 patients with ALS and 24 healthy controls. A further 9 patients with primary lateral sclerosis and a group of 15 asymptomatic carriers of genetic mutations associated with ALS were also studied.ResultsIncreased functional connectivity, particularly from the posterior cingulate cortex, was demonstrated in both patient groups compared to healthy controls. Directionally similar patterns were also evident in the asymptomatic genetic mutation carrier group.ConclusionIncreased cortical functional connectivity elevation is a quantitative marker that reflects ALS pathology across its clinical spectrum, and may develop during the presymptomatic period. The amelioration of pathologic magnetoencephalography signals might be a marker sensitive enough to provide proof-of-principle in the development of future neuroprotective therapeutics.

© 2018 Elsevier Inc., To identify novel genes associated with ALS, we undertook two lines of investigation. We carried out a genome-wide association study comparing 20,806 ALS cases and 59,804 controls. Independently, we performed a rare variant burden analysis comparing 1,138 index familial ALS cases and 19,494 controls. Through both approaches, we identified kinesin family member 5A (KIF5A) as a novel gene associated with ALS. Interestingly, mutations predominantly in the N-terminal motor domain of KIF5A are causative for two neurodegenerative diseases: hereditary spastic paraplegia (SPG10) and Charcot-Marie-Tooth type 2 (CMT2). In contrast, ALS-associated mutations are primarily located at the C-terminal cargo-binding tail domain and patients harboring loss-of-function mutations displayed an extended survival relative to typical ALS cases. Taken together, these results broaden the phenotype spectrum resulting from mutations in KIF5A and strengthen the role of cytoskeletal defects in the pathogenesis of ALS.

Background Reduction of precuneus choline acetyltransferase activity co-occurs with greater beta-amyloid (Aβ) in Alzheimer's disease (AD). Whether this cholinergic deficit is associated with alteration in nerve growth factor (NGF) signaling and its relation to Aβ plaque and neurofibrillary tangle (NFT) pathology during disease onset is unknown. Methods Precuneus NGF upstream and downstream signaling levels relative to Aβ and NFT pathology were evaluated using biochemistry and histochemistry in 62 subjects with a premortem diagnosis of non–cognitively impaired (NCI; n = 23), mild cognitive impairment (MCI; n = 21), and mild to moderate AD ( n = 18). Results Immunoblots revealed increased levels of proNGF in AD subjects but not MCI subjects, whereas cognate receptors were unchanged. There were no significant differences in protein level for the downstream survival kinase-signaling proteins Erk and phospho-Erk among groups. Apoptotic phospho-JNK, phospho-JNK/JNK ratio, and Bcl-2 were significantly elevated in AD subjects. Soluble Aβ 1–42 and fibrillar Aβ measured by [ 3 H] Pittsburgh compound-B ([ 3 H]PiB) binding were significantly higher in AD subjects compared with MCI and NCI subjects. The density of plaques showed a trend to increase, but only 6-CN-PiB–positive plaques reached significance in AD subjects. AT8-positive, TOC-1–positive, and Tau C3–positive NFT densities were unchanged, whereas only AT8-positive neuropil thread density was statistically higher in AD subjects. A negative correlation was found between proNGF, phospho-JNK, and Bcl-2 levels and phospho-JNK/JNK ratio and cognition, whereas proNGF correlated positively with 6-CN-PiB–positive plaques during disease progression. Conclusions Data indicate that precuneus neurotrophin pathways are resilient to amyloid toxicity during the onset of AD.

Homozygous loss-of-function mutations in optineurin (OPTN) are a rare cause of amyotrophic lateral sclerosis (ALS), whereas heterozygous loss-of-function mutations have been suggested to increase ALS disease risk. We report a patient with ALS and frontotemporal dementia (FTD) from the Clinical Research in ALS and Related Disorders for Therapeutic Development (CReATe) Consortium carrying compound heterozygous loss-of-function variants in OPTN. Quantitative real-time mRNA expression analyses revealed a 75-80% reduction in OPTN expression in blood in the OPTN carrier as compared to controls, suggesting at least partial nonsense-mediated decay of the mutant transcripts. This case report illustrates the diverse inheritance patterns and variable clinical presentations associated with OPTN mutations, and underscores the importance of complete OPTN gene screening in patients with ALS and related disorders, especially in the context of clinical genetic testing.

ObjectiveTo examine the safety and tolerability as well as the preliminary efficacy of arimoclomol, a heat shock protein co-inducer that promotes nascent protein folding, in patients with rapidly progressive SOD1 amyotrophic lateral sclerosis (ALS).MethodsThis was a double-blind, placebo-controlled trial in which patients with rapidly progressive SOD1-mutant ALS were randomized 1:1 to receive arimoclomol 200 mg tid or matching placebo for up to 12 months. Study procedures were performed using a mix of in-person and remote assessments. Primary outcome was safety and tolerability. Secondary outcome was efficacy, with survival as the principal measure. Additional efficacy measures were the rates of decline of the Revised ALS Functional Rating Scale (ALSFRS-R) and percent predicted forced expiratory volume in 6 seconds (FEV6), and the Combined Assessment of Function and Survival (CAFS).ResultsThirty-eight participants were randomized. Thirty-six (19 placebo, 17 arimoclomol) were included in the prespecified intent-to-treat analysis. Apart from respiratory function, groups were generally well-balanced at baseline. Adverse events occurred infrequently, and were usually mild and deemed unlikely or not related to study drug. Adjusting for riluzole and baseline ALSFRS-R, survival favored arimoclomol with a hazard ratio of 0.77 (95% confidence interval [CI] 0.32–1.80). ALSFRS-R and FEV6 declined more slowly in the arimoclomol group, with treatment differences of 0.5 point/month (95% CI −0.63 to 1.63) and 1.24 percent predicted/month (95% CI −2.77 to 5.25), respectively, and the CAFS similarly favored arimoclomol.ConclusionsThis study provides Class II evidence that arimoclomol is safe and well-tolerated at a dosage of 200 mg tid for up to 12 months. Although not powered for therapeutic effect, the consistency of results across the range of prespecified efficacy outcome measures suggests a possible therapeutic benefit of arimoclomol.Clinicaltrials.gov identifierNCT00706147.Classification of evidenceThis study provides Class II evidence that arimoclomol is safe and well-tolerated at a dosage of 200 mg tid for up to 12 months. The study lacked the precision to conclude, or to exclude, an important therapeutic benefit of arimoclomol.

To evaluate neurofilament light (NfL) as a biomarker of the presymptomatic phase of amyotrophic lateral sclerosis (ALS).The study population includes 84 individuals at risk for developing ALS, 34 controls, 17 ALS patients, and 10 phenoconverters (at-risk individuals observed both before and after the emergence of clinically manifest disease). At-risk individuals are enrolled through Pre-Symptomatic Familial ALS (Pre-fALS), a longitudinal natural history and biomarker study of individuals who are carriers of any ALS-associated gene mutation (in SOD1, C9orf72, TARDBP, FUS, VCP, etc), but who, at the time of enrollment, demonstrated no clinical symptoms or signs (including electromyographic evidence) of manifest disease. NfL in serum and cerebrospinal fluid (CSF) were quantified using an electrochemiluminescence immunoassay.Serum and CSF NfL are substantially higher in ALS patients compared to controls and at-risk individuals and remain relatively stable over time. Among phenoconverters, however, NfL levels were elevated (ie, above the range observed in controls) as far back as ∼12 months preceding the emergence of the earliest clinical symptoms or signs of disease.Serum (and CSF) NfL are informative biomarkers of presymptomatic ALS, providing a new tool to quantify presymptomatic disease progression and to potentially predict the timing of clinical phenoconversion. As such, quantification of NfL may aid the design and implementation of early therapeutic intervention for affected individuals and/or disease prevention trials for individuals at short-term risk of developing ALS. Ann Neurol 2018 Ann Neurol 2018;83:130-139.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.