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Purpose of review: To improve our clinical understanding of facial onset sensory and motor neuronopathy (FOSMN). Recent findings: We identified 29 new cases and 71 literature cases, resulting in a cohort of 100 patients with FOSMN. During follow-up, cognitive and behavioral changes became apparent in 8 patients, suggesting that changes within the spectrum of frontotemporal dementia (FTD) are a part of the natural history of FOSMN. Another new finding was chorea, seen in 6 cases. Despite reports of autoantibodies, there is no consistent evidence to suggest an autoimmune pathogenesis. Four of 6 autopsies had TAR DNA-binding protein (TDP) 43 pathology. Seven cases had genetic mutations associated with neurodegenerative diseases. Summary: FOSMN is a rare disease with a highly characteristic onset and pattern of disease progression involving initial sensory disturbances, followed by bulbar weakness with a cranial to caudal spread of pathology. Although not conclusive, the balance of evidence suggests that FOSMN is most likely to be a TDP-43 proteinopathy within the amyotrophic lateral sclerosis-FTD spectrum.

Copyright © 2022 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works., Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease with an estimated heritability between 40 and 50%. DNA methylation patterns can serve as proxies of (past) exposures and disease progression, as well as providing a potential mechanism that mediates genetic or environmental risk. Here, we present a blood-based epigenome-wide association study meta-analysis in 9706 samples passing stringent quality control (6763 patients, 2943 controls). We identified a total of 45 differentially methylated positions (DMPs) annotated to 42 genes, which are enriched for pathways and traits related to metabolism, cholesterol biosynthesis, and immunity. We then tested 39 DNA methylation-based proxies of putative ALS risk factors and found that high-density lipoprotein cholesterol, body mass index, white blood cell proportions, and alcohol intake were independently associated with ALS. Integration of these results with our latest genome-wide association study showed that cholesterol biosynthesis was potentially causally related to ALS. Last, DNA methylation at several DMPs and blood cell proportion estimates derived from DNA methylation data were associated with survival rate in patients, suggesting that they might represent indicators of underlying disease processes potentially amenable to therapeutic interventions., The research reported in this publication was supported by grants from The Dutch Research Council (NWO) (VENI scheme grant 09150161810018 to W.v.R.) and Prinses Beatrix Spierfond (neuromuscular fellowship grant W.F19-03 to W.v.R.), The Prinses Beatrix Spierfonds (W.OR20-08 to J.J.F.A.v.V. and J.H.V.), The Canadian Institutes of Health Research (FRN 159279 to J.P.R.), The Dutch Research Council (NWO) (VIDI grant 91719350 to K.P.K.), The European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (grant agreement no. 772376-EScORIAL to J.H.V.), the Swedish Brain Foundation (grant nos. 2012-0262, 2012-0305, 2013-0279, 2016-0303, 2018-0310, and 2020-0353 to P.M.A.), the Swedish Research Council (grant nos. 2012-3167 and 2017-03100 to P.M.A.), the Knut and Alice Wallenberg Foundation (grant nos. 2012.0091, 2014.0305, and 2020.0232 to P.M.A.), the Ulla-Carin Lindquist Foundation and the Västerbotten County Council (grant no. 56103-7002829 to P.M.A.), and King Gustaf V’s and Queen Victoria’s Freemason’s Foundation. This is an EU Joint Programme–Neurodegenerative Disease Research (JPND) project. The project is supported through the following funding organizations under the aegis of JPND (www.jpnd.eu) [United Kingdom, Medical Research Council (MR/L501529/1; MR/R024804/1) and Economic and Social Research Council (ES/L008238/1)] and through the Motor Neurone Disease Association (MNDA). This study represents independent research part funded by the National Institute for Health Research (NIHR) Biomedical Research Centre at South London and Maudsley NHS Foundation Trust and King’s College London. A.A.-C. is supported by an NIHR Senior Investigator Award. Samples used in this research were entirely/in part obtained from the U.K. National DNA Bank for MND Research, funded by the MND Association and the Wellcome Trust. We would like to thank people with MND and their families for their participation in this project. We acknowledge sample management undertaken by Biobanking Solutions funded by the Medical Research Council at the Centre for Integrated Genomic Medical Research, University of Manchester. R.J.P. is funded through the Gravitation program of the Dutch Ministry of Education, Culture, and Science and the Netherlands Organization for Scientific Research (BRAINSCAPES). G.L.S. was supported by a PhD studentship from the Alzheimer’s Society. S.T.N. acknowledges support through a FightMND Mid-Career Fellowship. V.S. is supported by the Italian Ministry of Health, AriSLA, and E-Rare Joint Transnational Call. A.A.K. is funded by the MNDA and NIHR Maudsley Biomedical Research Centre. D.B., E.T., and H.R. are employees of Biogen. L.H.v.d.B. reports grants from the Netherlands ALS Foundation, grants from The Netherlands Organization for Health Research and Development (Vici scheme), grants from The European Community’s Health Seventh Framework Programme [grant agreement no. 259867 (EuroMOTOR) to L.H.v.d.B.], and grants from The Netherlands Organization for Health Research and Development (the STRENGTH project, funded through the EU Joint Programme–Neurodegenerative Disease Research, JPND), during the conduct of the study. Project MinE Belgium was supported by a grant from IWT (no. 140935), the ALS Liga België, the National Lottery of Belgium, and the KU Leuven Opening the Future Fund. P.V.D. holds a senior clinical investigatorship of FWO-Vlaanderen and is supported by the E. von Behring Chair for Neuromuscular and Neurodegenerative Disorders, the ALS Liga België, and the KU Leuven funds “Een Hart voor ALS”, “Laeversfonds voor ALS Onderzoek”, and the “Valéry Perrier Race against ALS Fund”. This work was supported by the Italian Ministry of Health (Ministero della Salute, Ricerca Sanitaria Finalizzata, grant RF-2016-02362405 to A. Chiò), the Progetti di Rilevante Interesse Nazionale program of the Ministry of Education, University and Research (grant 2017SNW5MB to A. Chiò); the European Commission’s Health Seventh Framework Programme (FP7/2007-2013 under grant agreement 259867 to A. Chiò), and the Joint Programme–Neurodegenerative Disease Research (Strength, ALS-Care and Brain-Mend projects), granted by Italian Ministry of Education, University, and Research. This study was performed under the Department of Excellence grant of the Italian Ministry of Education, University and Research to the “Rita Levi Montalcini” Department of Neuroscience, University of Torino, Italy. We acknowledge funding from the Australian National Health and Medical Research (NHMRC) Council: 1151854, 1083187, 1173790, 1078901, 1113400, 1095215, and 1176913 Enabling Grant #402703 to N.R.W. Additional funding was provided by the Motor Neurone Disease Research Institute of Australia Ice Bucket Challenge grant for the SALSA-SGC consortium. The OATS (used for controls) was facilitated through Twins Research Australia, a national resource in part supported by a Centre for Research Excellence from the Australian NHMRC Council (NHMRC 1079102 to N.R.W.). Funding for this study was awarded by the (NHMRC)/Australian Research Council Strategic Award (grant 401162 to N.R.W.) and NHMRC grants (1405325, 1024224, 1025243, 1045325, 1085606, 568969, and 1093083 to N.R.W.). The collaboration project is cofunded by the PPP Allowance made available by Health~Holland, Top Sector Life Sciences & Health, to stimulate public-private partnerships. This study was supported by the ALS Foundation Netherlands. This work was sponsored by NWO Domain Science for the use of the national computer facilities. A.N.B. is grateful to the Suna and Inan Kirac Foundation and Koc University for the excellent research environment created and for financial support. G.A.R. is supported by the Canadian Institutes of Health. Several authors of this publication are members of the Netherlands Neuromuscular Center (NL-NMD) and the European Reference Network for rare neuromuscular diseases EURO-NMD. French ALS patients of the Pitié-Salpêtrière hospital (Paris) have been collected with ARSla funding support.

Introduction Traumatic brain injury (TBI) is the main cause of death in children around the world. The last Dutch epidemiological study described the incidence over 10 years ago. Mechanism of injury seems to change with the age of the child, therefore it is important to appreciate different age groups. To be able to lower the impact of childhood TBI, an understanding of current incidence, mechanism of injury and outcome is necessary. Methods A nationwide retrospective cohort study was conducted. The Dutch National Trauma Database was used to identify all patients 18 years and younger who were admitted to a Dutch hospital with moderate-severe TBI (Abbreviated Injury Score≥3) in the Netherlands, from January 2015 until December 2017. Subanalyses were done for different age groups. Results In total, 1413 patients were included, of whom 5% died. The incidence rate of moderate-severe TBI was 14/100,000 person years. Median age was 10.4 years. Largest age group was patients

Here, we provide a case-report of an amyotrophic lateral sclerosis (ALS) patient with cognitive deficits best defined as posterior cortical atrophy (PCA). This is an unusual finding as ALS forms a spectrum with frontotemporal dementia (FTD), whereas PCA is predominantly associated with Alzheimer’s disease pathology. We hypothesize on whether ALS with PCA might be an under recognized phenotype considering multiple imaging studies in ALS have also reported (asymptomatic) parietal atrophy.

ObjectiveTo assess time trends in motor neuron disease (MND) incidence, prevalence, and mortality and to investigate geographic clustering of MND cases in the Netherlands from 1998 to 2017, we analyzed data from the Netherlands Personal Records database, the Netherlands MND Center, and the Netherlands Patient Association of Neuromuscular Diseases.MethodsIn this prospective cohort study, Poisson regression was used to assess time trends in MND risk. We calculated age- and sex-standardized, observed, and expected cases for 1,694 areas. Bayesian smoothed risk mapping was used to investigate geographic MND risk.ResultsWe identified 7,992 MND cases, reflecting an incidence of 2.64 (95% confidence interval [CI] 2.62–2.67) per 100,000 person-years and a prevalence of 9.5 (95% CI 9.1–10.0) per 100,000 persons. Highest age-standardized prevalence and mortality rates occurred at a later age in men than in women (p < 0.001). Unadjusted mortality rates increased by 53.2% from 2.57 per 100,000 person-years in 1998 to 3.86 per 100,000 person-years in 2017. After adjustment for age and sex, an increase in MND mortality rate of 14.1% (95% CI 5.7%–23.2%, p < 0.001) remained. MND relative risk ranged from 0.78 to 1.43 between geographic areas; multiple urban and rural high-risk areas were identified.ConclusionsWe found a significant national increase in MND mortality from 1998 through 2017, explained only partly by an aging Dutch population, and a geographic variability in MND risk, suggesting a role for environmental or demographic risk factors.

In the version of this article initially published, the affiliation for Nazli Başak appeared incorrectly. Nazli Başak is at Koç University, School of Medicine, KUTTAM-NDAL, Istanbul, Turkey, and not Bogazici University. The error has been corrected in the HTML and PDF versions of the article.

OBJECTIVE\ud \ud To assess whether genetic subgroups in recent amyotrophic lateral sclerosis (ALS) trials responded to treatment with lithium carbonate, but that the treatment effect was lost in a large cohort of nonresponders.\ud \ud METHODS\ud \ud Individual participant data were obtained from 3 randomized trials investigating the efficacy of lithium carbonate. We matched clinical data with data regarding the UNC13A and C9orf72 genotype. Our primary outcome was survival at 12 months. On an exploratory basis, we assessed whether the effect of lithium depended on the genotype.\ud \ud RESULTS\ud \ud Clinical data were available for 518 of the 606 participants. Overall, treatment with lithium carbonate did not improve 12-month survival (hazard ratio [HR] 1.0, 95% confidence interval [CI] 0.7-1.4; p = 0.96). Both the UNC13A and C9orf72 genotype were independent predictors of survival (HR 2.4, 95% CI 1.3-4.3; p = 0.006 and HR 2.5, 95% CI 1.1-5.2; p = 0.032, respectively). The effect of lithium was different for UNC13A carriers (p = 0.027), but not for C9orf72 carriers (p = 0.22). The 12-month survival probability for UNC13A carriers treated with lithium carbonate improved from 40.1% (95% CI 23.2-69.1) to 69.7% (95% CI 50.4-96.3).\ud \ud CONCLUSIONS\ud \ud This study incorporated genetic data into past ALS trials to determine treatment effects in a genetic post hoc analysis. Our results suggest that we should reorient our strategies toward finding treatments for ALS, start focusing on genotype-targeted treatments, and standardize genotyping in order to optimize randomization and analysis for future clinical trials.

INTRODUCTION: Amyotrophic lateral sclerosis (ALS) is a fatal disorder characterized by the progressive loss of upper and lower motor neurons. ALS has traditionally been classified within the domain of neuromuscular diseases, which are a unique spectrum of disorders that predominantly affect the peripheral nervous system. However, over the past decades compounding evidence has emerged that there is extensive involvement of the central nervous system. Therefore, one can question whether it remains accurate to classify ALS as a neuromuscular disorder. AREAS COVERED: In this review, the authors sought to discuss current approaches toward disease classification and how we should classify ALS based on novel insights from clinical, imaging, pathophysiological, neuropathological and genetic studies. EXPERT OPINION: ALS exhibits the cardinal features of a neurodegenerative disease. Therefore, classifying ALS as a neuromuscular disease in the strict sense has become untenable. Diagnosing ALS however does require significant neuromuscular expertise and therefore neuromuscular specialists remain best equipped to evaluate this category of patients. Designating motor neuron diseases as a separate category in the ICD-11 is justified and adequately deals with this issue. However, to drive effective therapy development the fields of motor neuron disease and neurodegenerative disorders must come together.

Because hyper-excitability has been shown to be a shared pathophysiological mechanism, we used the latest and largest genome-wide studies in amyotrophic lateral sclerosis (n = 36,052) and epilepsy (n = 38,349) to determine genetic overlap between these conditions. First, we showed no significant genetic correlation, also when binned on minor allele frequency. Second, we confirmed the absence of polygenic overlap using genomic risk score analysis. Finally, we did not identify pleiotropic variants in meta-analyses of the 2 diseases. Our findings indicate that amyotrophic lateral sclerosis and epilepsy do not share common genetic risk, showing that hyper-excitability in both disorders has distinct origins. ispartof: NEUROBIOLOGY OF AGING vol:92 ispartof: location:United States status: published

Increasingly, repeat expansions are being identified as part of the complex genetic architecture of amyotrophic lateral sclerosis. To date, several repeat expansions have been genetically associated with the disease: intronic repeat expansions in C9orf72, polyglutamine expansions in ATXN2 and polyalanine expansions in NIPA1. Together with previously published data, the identification of an amyotrophic lateral sclerosis patient with a family history of spinocerebellar ataxia type 1, caused by polyglutamine expansions in ATXN1, suggested a similar disease association for the repeat expansion in ATXN1. We, therefore, performed a large-scale international study in 11 700 individuals, in which we showed a significant association between intermediate ATXN1 repeat expansions and amyotrophic lateral sclerosis (P = 3.33 × 10−7). Subsequent functional experiments have shown that ATXN1 reduces the nucleocytoplasmic ratio of TDP-43 and enhances amyotrophic lateral sclerosis phenotypes in Drosophila, further emphasizing the role of polyglutamine repeat expansions in the pathophysiology of amyotrophic lateral sclerosis., Repeat expansions are being identified as part of the complex genetic architecture of amyotrophic lateral sclerosis. This study shows a significant association between intermediate ATXN1 repeat expansions and amyotrophic lateral sclerosis, possibly via mislocalization of TDP-43, further emphasizing the role of polyglutamine expansions in the pathophysiology of amyotrophic lateral sclerosis., Graphical Abstract Graphical Abstract

Background: Primary lateral sclerosis (PLS) is a rare motor neuron disease characterized by progressive degeneration of upper motor neurons, resulting in spasticity and disability. There is, however, mounting evidence that the disease is not limited to upper motor neurons alone and that cognitive and behavioral changes within the spectrum of frontotemporal dementia (FTD) are part of the clinical phenotype. Objectives: To provide an in-depth classification of the cognitive and behavioral profiles of PLS by using the golden standard, a full neuropsychological evaluation, as well as a comprehensive behavioral assessment in a cohort of 30 cases. Results: Only 7 out of 30 PLS patients scored within normal range on all of the tests within our battery. The neuropsychological profile of PLS consists of deficits in social cognition (affective theory of mind (ToM) in particular), fluency, executive functions and memory. Using the revised Strong criteria, we could classify 57% of patients within the FTD spectrum (of which 17% had behavioral variant FTD). An additional 20% of patients had deficits which were not characteristic of FTD. Conclusions: This study confirms that PLS is not a restricted phenotype (only affecting upper motor neurons) and that behavioral and cognitive changes are common. Therefore, clinicians treating PLS patients should routinely assess cognition and behavior as part of routine care as cognitive and behavioral changes impact management, decision-making and care-giver burden. This assessment should be sensitive to the neuropsychological profile of PLS (social cognition (affective ToM in particular), fluency, executive functions and memory) and behavioral changes.

NIPA1 (nonimprinted in Prader-Willi/Angelman syndrome 1) mutations are known to cause hereditary spastic paraplegia type 6, a neurodegenerative disease that phenotypically overlaps to some extent with amyotrophic lateral sclerosis (ALS). Previously, a genomewide screen for copy number variants found an association with rare deletions in NIPA1 and ALS, and subsequent genetic analyses revealed that long (or expanded) polyalanine repeats in NIPA1 convey increased ALS susceptibility. We set out to perform a large-scale replication study to further investigate the role of NIPA1 polyalanine expansions with ALS, in which we characterized NIPA1 repeat size in an independent international cohort of 3955 patients with ALS and 2276 unaffected controls and combined our results with previous reports. Meta-analysis on a total of 6245 patients with ALS and 5051 controls showed an overall increased risk of ALS in those with expanded (>8) GCG repeat length (odds ratio = 1.50, p = 3.8×10-5). Together with previous reports, these findings provide evidence for an association of an expanded polyalanine repeat in NIPA1 and ALS. ispartof: NEUROBIOLOGY OF AGING vol:74 ispartof: location:United States status: published

ObjectivesCognitive and behavioural changes within the spectrum of frontotemporal dementia (FTD) are observed frequently in patients with amyotrophic lateral sclerosis (ALS). Whether these changes also occur in other forms of motor neuron disease (MND) is not well studied. We therefore systemically screened a large cohort of patients with primary lateral sclerosis (PLS) and progressive muscular atrophy (PMA) for cognitive and behavioural changes, and subsequently compared our findings with a cohort of patients with ALS.MethodsUsing a set of screening instruments (Edinburgh Cognitive and Behavioural ALS Screen, ALS and Frontotemporal Dementia Questionnaire, Frontal Assessment Battery, and Hospital Anxiety and Depression Scale), the presence of cognitive and behavioural changes as well as anxiety and depression in 277 patients with ALS, 75 patients with PLS and 143 patients with PMA was evaluated retrospectively.ResultsWe found a high frequency of cognitive and behavioural abnormalities with similar profiles in all three groups. Subjects with behavioural variant FTD were identified in all groups.ConclusionsThe percentage of patients with PLS and PMA with cognitive dysfunction was similar to patients with ALS, emphasising the importance for cognitive screening as part of routine clinical care in all three patient groups. With a similar cognitive profile, in line with genetic and clinical overlap between the MNDs, the view of PLS as an MND exclusively affecting upper motor neurons and PMA exclusively affecting lower motor neurons cannot be held. Therefore, our findings are in contrast to the recently revised El Escorial criteria of 2015, where PLS and PMA are described as restricted phenotypes. Our study favours a view of PLS and PMA as multidomain diseases similar to ALS.

Amyotrophic lateral sclerosis (ALS) is underpinned by an oligogenic rare variant architecture. Identified genetic variants of ALS include RNA-binding proteins containing prion-like domains (PrLDs). We hypothesized that screening genes encoding additional similar proteins will yield novel genetic causes of ALS. The most common genetic variant of ALS patients is a G4C2-repeat expansion within C9ORF72. We have shown that G4C2-repeat RNA sequesters RNA-binding proteins. A logical consequence of this is that loss-of-function mutations in G4C2-binding partners might contribute to ALS pathogenesis independently of and/or synergistically with C9ORF72 expansions. Targeted sequencing of genomic DNA encoding either RNA-binding proteins or known ALS genes (n = 274 genes) was performed in ALS patients to identify rare deleterious genetic variants and explore genotype-phenotype relationships. Genomic DNA was extracted from 103 ALS patients including 42 familial ALS patients and 61 young-onset (average age of onset 41 years) sporadic ALS patients; patients were chosen to maximize the probability of identifying genetic causes of ALS. Thirteen patients carried a G4C2-repeat expansion of C9ORF72. We identified 42 patients with rare deleterious variants; 6 patients carried more than one variant. Twelve mutations were discovered in known ALS genes which served as a validation of our strategy. Rare deleterious variants in RNA-binding proteins were significantly enriched in ALS patients compared to control frequencies (p = 5.31E-18). Nineteen patients featured at least one variant in a RNA-binding protein containing a PrLD. The number of variants per patient correlated with rate of disease progression (t-test, p = 0.033). We identified eighteen patients with a single variant in a G4C2-repeat binding protein. Patients with a G4C2-binding protein variant in combination with a C9ORF72 expansion had a significantly faster disease course (t-test, p = 0.025). Our data are consistent with an oligogenic model of ALS. We provide evidence for a number of entirely novel genetic variants of ALS caused by mutations in RNA-binding proteins. Moreover we show that these mutations act synergistically with each other and with C9ORF72 expansions to modify the clinical phenotype of ALS. A key finding is that this synergy is present only between functionally interacting variants. This work has significant implications for ALS therapy development.

Identifying large repeat expansions such as those that cause amyotrophic lateral sclerosis (ALS) and Fragile X syndrome is challenging for short-read (100-150 bp) whole genome sequencing (WGS) data. A solution to this problem is an important step towards integrating WGS into precision medicine. We have developed a software tool called ExpansionHunter that, using PCR-free WGS short-read data, can genotype repeats at the locus of interest, even if the expanded repeat is larger than the read length. We applied our algorithm to WGS data from 3,001 ALS patients who have been tested for the presence of the C9orf72 repeat expansion with repeat-primed PCR (RP-PCR). Taking the RP-PCR calls as the ground truth, our WGS-based method identified pathogenic repeat expansions with 98.1% sensitivity and 99.7% specificity. Further inspection identified that all 11 conflicts were resolved as errors in the original RP-PCR results. Compared against this updated result, ExpansionHunter correctly classified all (212/212) of the expanded samples as either expansions (208) or potential expansions (4). Additionally, 99.9% (2,786/2,789) of the wild type samples were correctly classified as wild type by this method with the remaining two identified as possible expansions. We further applied our algorithm to a set of 144 samples where every sample had one of eight different pathogenic repeat expansions including examples associated with fragile X syndrome, Friedreich’s ataxia and Huntington’s disease and correctly flagged all of the known repeat expansions. Finally, we tested the accuracy of our method for short repeats by comparing our genotypes with results from 860 samples sized using fragment length analysis and determined that our calls were >95% accurate. ExpansionHunter can be used to accurately detect known pathogenic repeat expansions and provides researchers with a tool that can be used to identify new pathogenic repeat expansions.

BACKGROUND: The Edinburgh cognitive and behavioral ALS screen (ECAS) was developed specifically to detect cognitive and behavioral changes in patients with amyotrophic lateral sclerosis (ALS). Differences with regard to normative data of different (language) versions of neuropsychological tests such as the ECAS exist. OBJECTIVE: To derive norms for the Dutch version of the ECAS. METHODS: Normative data were derived from a large sample of 690 control subjects and cognitive profiles were compared between a matched sample of 428 patients with ALS and 428 control subjects. RESULTS: Age, level of education, and sex were significantly associated with performance on the ECAS in the normative sample. ECAS data were not normally distributed and therefore normative data were expressed as percentile ranks. The comparison of ECAS scores between patients and control subjects demonstrated that patients obtained significantly lower scores for language, executive function, verbal fluency, and memory, which is in line with the established cognitive profile of ALS. CONCLUSION: For an accurate interpretation of ECAS results, it is important to derive normative data in large samples with nonparametric methods. The present normative data provide healthcare professionals with an accurate estimate of how common or uncommon patients' ECAS scores are and provide a useful supplement to existing cut-off scores. ispartof: AMYOTROPHIC LATERAL SCLEROSIS AND FRONTOTEMPORAL DEGENERATION vol:20 issue:1-2 pages:19-27 ispartof: location:England status: published

Substantial clinical, pathological, and genetic overlap exists between amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). TDP-43 inclusions have been found in both ALS and FTD cases (FTD-TDP). Recently, a repeat expansion in C9orf72 was identified as the causal variant in a proportion of ALS and FTD cases. We sought to identify additional evidence for a common genetic basis for the spectrum of ALS-FTD.We used published genome-wide association studies data for 4,377 ALS patients and 13,017 controls, and 435 pathology-proven FTD-TDP cases and 1,414 controls for genotype imputation. Data were analyzed in a joint meta-analysis, by replicating topmost associated hits of one disease in the other, and by using a conservative rank products analysis, allocating equal weight to ALS and FTD-TDP sample sizes.Meta-analysis identified 19 genome-wide significant single nucleotide polymorphisms (SNPs) in C9orf72 on chromosome 9p21.2 (lowest p = 2.6 × 10(-12) ) and 1 SNP in UNC13A on chromosome 19p13.11 (p = 1.0 × 10(-11) ) as shared susceptibility loci for ALS and FTD-TDP. Conditioning on the 9p21.2 genotype increased statistical significance at UNC13A. A third signal, on chromosome 8q24.13 at the SPG8 locus coding for strumpellin (p = 3.91 × 10(-7) ) was replicated in an independent cohort of 4,056 ALS patients and 3,958 controls (p = 0.026; combined analysis p = 1.01 × 10(-7) ).We identified common genetic variants in C9orf72, but in addition in UNC13A that are shared between ALS and FTD. UNC13A provides a novel link between ALS and FTD-TDP, and identifies changes in neurotransmitter release and synaptic function as a converging mechanism in the pathogenesis of ALS and FTD-TDP.