Abstract The Scottish Travellers are a traditionally nomadic community in Scotland that has historically been marginalised, and remained socially isolated from the settled Scottish population until recently. Little, however, is known about their genetic origins, population structure and risks of Mendelian disease. After an approach from the community to address this gap and increase representation, we analyzed array genotypes and whole-exome sequencing data from up to 125 Gypsy/Traveller individuals, alongside settled British and Irish references. We demonstrate that Scottish Travellers are genetically distinct from Irish Travellers, English Gypsies and European Roma, as well as the settled British and Irish populations. However, they do share autosomal and mitochondrial genetic ancestry with settled Scots. Two genetic subgroups are detectable: one which is more drifted and one more admixed. High levels of autozygosity are apparent, consistent with consanguinity. We detect signals of bottlenecks in autosomal and mitochondrial data. Importantly, we identified an enrichment of rare, pathogenic variants, including at least five putative founder variants associated with recessive Mendelian disorders. These findings provide insights into the genetic history of the Scottish Traveller population and highlight the opportunity and need for community-driven clinical genetics screening initiatives to decrease the scope for further health disparities.

Sex differences, in terms of prevalence, symptoms and disease progression, are established in the aetiology of complex neurodegenerative diseases, including amyotrophic lateral sclerosis, Parkinson's disease and Alzheimer's disease, but the underlying biology driving these differences remains poorly understood. There is emerging evidence from genetic and functional analyses affirming the role of the immune system in such diseases, but a thorough assessment of sex differences in the link between the immune system and neurodegenerative diseases remains lacking.Here, we applied a robust causal inference approach, two-sample Mendelian randomization, to evaluate the causal effect of immune-related protein levels on three neurodegenerative diseases with large-scale sex-stratified genome-wide association data available: amyotrophic lateral sclerosis (females = 10 895 cases, 57 062 controls; males = 15 547 cases, 50 145 controls); Parkinson's disease (females = 7947 cases, 90 662 controls; males = 13 020 cases, 89 660 controls); and Alzheimer's disease (females = 18 822 cases, 281 415 controls; males = 17 293 cases, 213 339 controls). As exposures, we focused on 932 immune system-related proteins with significant protein cis-quantitative trait loci (false discovery rate cut-off < 0.01) from a large sex-combined plasma protein dataset (n = 33 477), for which corresponding genes were included in the Immunology Database and Analysis Portal gene list. We tested for a causal relationship between genetically predicted levels of each of these proteins and each neurodegenerative disease in sex-stratified and sex-combined data, followed by colocalization and estimation of sex-differential effects. We additionally performed exploratory analyses using sex-combined CSF protein cis-quantitative trait loci (n = 971) as exposures.We observed evidence for a sex-differential causal relationship between FCGR2A and Parkinson's disease and between CD2AP, MAMDC2, PCDH17 or CSF3 and Alzheimer's disease. We validated significant results using two independent protein cis-quantitative trait loci datasets for those plasma proteins available. After performing sensitivity analyses, we validated the potential causal relationships of OMG on Parkinson's disease and of GRN, SERPINF2 and TREM2 on Alzheimer's disease. Mendelian randomization with CSF protein cis-quantitative trait loci showed a potential causal effect of ADGRE2, GPNMB and COLEC11 on Parkinson's disease and of CD33 on Alzheimer's disease, without evidence of sex-differential effects. Finally, we substantiated our findings of protein-disease pairs using triangulation, specifically reporting independent supporting evidence from the literature and drug-related databases.Overall, our results point to potential causal effects of genetically predicted levels of immune system-related plasma and CSF proteins in Alzheimer's disease and Parkinson's disease, some of which may be considered as potential candidates for drug development.

Amyotrophic lateral sclerosis (ALS) is a heritable disorder where rare variants with low-to-moderate penetrance are thought to dominate genetic risk. To identify such rare variants, we harmonized and analyzed exome data from 22 cohorts, totaling 17,919 individuals with ALS and 200,703 controls across discovery and replication phases. Rare variant analyses identified several new risk genes, with replication confirming association of YKT6 and supporting HTR3C, GBGT1 and KNTC1. We also provide strong, independent validation for genes with limited previous evidence: ARPP21, DNAJC7 and CFAP410. Notably, in ARPP21, we identified a new high-effect variant (p.P747L) and confirmed that p.P563L is an ALS-associated variant leading to an aggressive disease course. Beyond new discoveries, our analyses largely recapitulated the known genetic architecture of ALS, identifying risk variants in over 20% of cases and supporting a cumulative oligogenic risk model. These findings highlight new translational targets and show that rare variant analyses capture substantially more genetic risk than common variant genome-wide association studies.

Background Despite several studies suggesting a potential oligogenic risk model in amyotrophic lateral sclerosis (ALS), case–control statistical evidence implicating oligogenicity with disease risk or clinical outcomes is limited. Considering its direct clinical and therapeutic implications, we aim to perform a large-scale robust investigation of oligogenicity in ALS risk and in the disease clinical course. Methods We leveraged Project MinE genome sequencing datasets (6711 cases and 2391 controls) to identify associations between oligogenicity in known ALS genes and disease risk, as well as clinical outcomes. Results In both the discovery and replication cohorts, we observed that the risk imparted from carrying multiple ALS rare variants was significantly greater than the risk associated with carrying only a single rare variant, both in the presence and absence of variants in the most well-established ALS genes. However, in contrast to risk, the relationships between oligogenicity and ALS clinical outcomes, such as age of onset and survival, did not follow the same pattern. Conclusions Our findings represent the first large-scale, case–control assessment of oligogenicity in ALS and show that oligogenic events involving known ALS risk genes are relevant for disease risk in ~6% of ALS but not necessarily for disease onset and survival. This must be considered in genetic counselling and testing by ensuring to use comprehensive gene panels even when a pathogenic variant has already been identified. Moreover, in the age of stratified medication and gene therapy, it supports the need for a complete genetic profile for the correct choice of therapy in all ALS patients.

While subtle yet discrete clusters of genetic identity across Ireland and Britain have been identified, their recent demographic history is unclear. Using genotype data from 6574 individuals with associated regional Irish or British ancestry, we identified genetic communities by applying Leiden community detection. Using haplotype segments segregated by length as proxy for time, we inferred regional Irish and British demographic histories. Using a subset of Irish participants, we provide genealogical context by estimating the enrichment/depletion of surnames within the Irish genetic communities. Through patterns of haplotype sharing, we find evidence of recent population bottlenecks in Orcadian, Manx and Welsh genetic communities. We observed temporal changes in genetic affinities within and between genetic communities in Ireland and Britain. Structure in Ireland is subtler compared to neighbouring British communities, with the Irish groups sharing relatively more short haplotype segments. In addition, we detected varying degrees of genetic isolation in peripheral Irish and British genetic communities across different time periods. Further, we observe a stable migration corridor between north-east Ireland and south-west Scotland while there is a recent migration barrier between south-east and west Ireland. Genealogical analysis of surnames in Ireland reflects history—Anglo-Norman surnames are enriched in the Wexford community while Scottish and Gallowglass surnames were enriched in the Ulster community. Using these new insights into the regional demographic history of Ireland and Britain across different time periods, we hope to understand the driving forces of rare allele frequencies and disease risk association within these populations.

Frontotemporal lobar degeneration encompasses a spectrum of clinically, radiologically, and molecularly heterogeneous conditions. Clinical phenotypes are defined based on predominant neuropsychological manifestations and the selective involvement of specific brain regions determines the core symptoms, disability profiles, and care needs. While the unique anatomical patterns of cortical and subcortical degeneration along the FTLD/FTD spectrum are well recognised, the molecular basis of this selective vulnerability remains unclear. A large prospective neuroimaging study has been undertaken to explore topological associations between phenotype-specific atrophy patterns and physiological mitochondrial density along the FTLD/FTD spectrum. Patients with behavioural variant FTD (bvFTD), nonfluent variant primary progressive aphasia (nfvPPA), semantic variant primary progressive aphasia (svPPA), C9orf72-positive ALS-FTD, C9orf72-negative ALS-FTD, and a cohort of healthy controls (HC) were included. FTD phenotypes were first contrasted to healthy controls and the resulting voxelwise maps were correlated to physiological mitochondrial density maps. We have identified voxelwise associations between atrophic change and physiological mitochondrial density. The resulting correlation coefficients over the entire GM mask revealed weak topological associations with r = 0.217 in C9NEG ALS-FTD, r = 0.251 in C9POS ALS-FTD, r = 0.213 in bvFTD, r = 0.182 in nfvPPA, and r = 0.292 in svPPA at p FWE < 0.001. Our region-of-interest analyses revealed moderate-to-strong regional associations between mitochondrial density and focal degenerative change with r values above 0.65 in multiple brain regions in all five FTD subgroups. Brain regions exhibiting the most significant associations between volume loss and mitochondrial density in each FTD subgroup are the very regions that define the core clinical manifestations of the given phenotype. Cortical and subcortical brain regions with high physiological mitochondrial density are particularly vulnerable to neurodegenerative change in FTD. While these anatomical associations do not indicate direct causation, mitochondrial metabolism may represent an important component in the cascade of focal degeneration.

BackgroundThe thalamus is a key subcortical hub of numerous corticobasal and corticocortical circuits mediating a wealth of cognitive, behavioural, sensory and motor processes. While thalamic pathology is increasingly recognised in amyotrophic lateral sclerosis, its degeneration is often assessed in isolation instead of adopting a network-wise perspective and assessing the integrity of its rich cortical projections.MethodsA prospective imaging study was conducted in a cohort of genetically stratified patients to assess the structural and functional integrity of thalamo-cortical circuits and volumetric alterations longitudinally.ResultsThe white matter integrity of thalamic projections to the anterior cingulate cortex, cerebellum, dorsolateral prefrontal cortex (DLPFC), Heschl's gyrus, medial frontal gyrus (MFG), orbitofrontal cortex, parietal cortex, postcentral gyrus and precentral gyrus (PreCG) is affected at baseline in ALS, which is more marked in C9orf72 hexanucleotide repeat carriers. Precentral gyrus and cerebellar grey matter volumes are also reduced, particularly in C9orf72. Longitudinal analyses capture progressive disconnection between the thalamus and frontal regions (DLPFC and MFG) in both C9orf72 positive and sporadic patients and progressive thalamo-PreCG disconnection in the sporadic C9orf72 negative cohort. Functional connectivity analyses revealed increasing thalamo-cerebellar connectivity in sporadic ALS and increasing thalamo-DLPFC connectivity in intermediate-length CAG repeat expansion carriers in ATXN2 over time.DiscussionOur data provide evidence of extensive thalamo-cortical connectivity alterations in ALS. Corticobasal circuits mediating extrapyramidal, somatosensory, cognitive and behavioural functions are increasingly affected as the disease progresses. The degeneration of thalamic projections support the conceptualisation of ALS as a 'network disease' and the notion of 'what wires together degenerates together'.

Amyotrophic lateral sclerosis (ALS) is thought to be caused by interaction between genetic and environmental factors leading to motor neuron (MN) degeneration. Physical exercise has been linked to ALS but controversy remains. A key question is to determine which individuals might be at risk of exercise-associated ALS, because unnecessary avoidance of exercise could be harmful. We implemented complementary strategies including Mendelian randomization (MR) and multiple questionnaire-based measures of physical exercise in different cohorts. We include a prospective study involving UK Biobank participants where we could test for a relationship between exercise and the timing of future ALS symptom onset. To interrogate the molecular basis of our observations we performed a genetic association study of 'extreme' exercise, equivalent to >6 h of strenuous exercise or >12 h of any leisure-time exercise per week. Our data suggest that the link between increased physical exercise and ALS is particularly important for males who perform the most activity; with no evidence of a link in females. We determined that extreme exercise in males is associated with loss-of-function genetic variants within a number of mammalian target of rapamycin (mTOR) signalling genes that are also differentially expressed in ALS spinal cord. Activity-induced mTOR signalling has been shown to selectively benefit MN. Therefore, our findings could imply that moderate exercise is neuroprotective via enhanced mTOR signalling, but extreme exercise in men is associated with neurotoxicity and ALS via a failure of this mechanism. There was no significant overlap between genes associated with extreme exercise and those associated with ALS risk, consistent with a true gene-environment interaction rather than a shared genetic basis. We are not yet able to make individual-level recommendations regarding exercise and risk of ALS, but our conclusions should provide focus for future investigation.

OBJECTIVE:Amyotrophic lateral sclerosis (ALS) has a very specific neuroimaging signature, but the molecular underpinnings of the strikingly selective anatomic involvement have not elucidated to date. Accordingly, a large neuroimaging study was conducted with 258 participants to evaluate associations between patterns of neurodegeneration and focal metabolic metrics. METHODS:Structural and diffusivity alterations were systematically evaluated in a genetically stratified cohort. Voxelwise associations between neurodegeneration and physiological mitochondrial indices were systematically evaluated over the entire brain and also examined in specific regions. RESULTS:Significant topological associations were identified between physiological mitochondria tissue density, nicotinamide adenine dinucleotide (NADH)-ubiquinone oxidoreductase, succinate dehydrogenase, cytochrome c oxidase (COX), mitochondrial respiratory capacity (MRC), tissue respiratory capacity (TRC), and propensity to focal atrophy in ALS. Anatomic correlations between mitochondrial metrics and morphometric change were particularly strong in GGGGCC hexanucleotide repeat carriers in C9orf72. Diffusivity analyses also confirmed associations between brain metabolism and microstructural degeneration. Higher focal mitochondria tissue density was associated with higher likelihood of frontal, temporal, cerebellar, opercular, thalamic, cingulum, putamen, corpus callosum, and corona radiata degeneration. Uncinate fasciculus degeneration was associated with higher Complex I, II, COX, and TRC activity. Topological associations were readily replicated in an external validation cohort. INTERPRETATION:Our data indicate that brain regions with high metabolic activity are particularly vulnerable to neurodegeneration in ALS. Anatomic associations between physiological cerebral metabolism and patterns of neurodegeneration implicate mitochondrial dysfunction in the pathophysiology of ALS. Although mitochondrial dysfunction may not be the primary etiological factor, it may represent a shared bottleneck of multiple converging molecular and genetic pathways, offering a potential opportunity for meaningful pharmacological intervention. ANN NEUROL 2026;99:614-628.

Background Primary lateral sclerosis (PLS) is traditionally solely associated with progressive upper motor neuron dysfunction manifesting in limb spasticity, gait impairment, bulbar symptoms and pseudobulbar affect. Recent studies have described frontotemporal dysfunction in some patients resulting in cognitive manifestations. Cerebellar pathology is much less well characterised despite sporadic reports of cerebellar disease. Methods A multi-timepoint, longitudinal neuroimaging study was conducted to characterise the evolution of both intra-cerebellar disease burden and cerebro-cerebellar connectivity. The volumes of deep cerebellar nuclei, cerebellar cortical volumes, cerebro-cerebellar structural and functional connectivity were assessed longitudinally in a cohort of 43 individuals with PLS. Results Cerebello-frontal, -temporal, -parietal, -occipital and cerebello-thalamic structural disconnection was detected at baseline based on radial diffusivity (RD) and cerebello-frontal decoupling was also evident based on fractional anisotropy (FA) alterations. Functional connectivity changes were also detected in cerebello-frontal, parietal and occipital projections. Volume reductions were identified in the vermis, anterior lobe, posterior lobe, and crura. Among the deep cerebellar nuclei, the dorsal dentate was atrophic. Longitudinal follow-up did not capture statistically significant progressive changes. Significant primary motor cortex atrophy and inter-hemispheric transcallosal degeneration were also captured. Conclusions PLS is not only associated with upper motor neuron dysfunction, but cerebellar cortical volume loss and deep cerebellar nuclear atrophy can also be readily detected. In addition to intra-cerebellar disease burden, cerebro-cerebellar connectivity alterations also take place. Our data add to the evolving evidence of widespread neurodegeneration in PLS beyond the primary motor regions. Cerebellar dysfunction in PLS is likely to exacerbate bulbar, gait and dexterity impairment and contribute to pseudobulbar affect.

We present a comparison of machine learning methods for the prediction of four quantitative traits in Arabidopsis thaliana. High prediction accuracies were achieved on individuals grown under standardized laboratory conditions from the 1001 Arabidopsis Genomes Project. An existing body of evidence suggests that linear models may be impeded by their inability to make use of non-additive effects to explain phenotypic variation at the population level. The results presented here use a nested cross-validation approach to confirm that some machine learning methods have the ability to statistically outperform linear prediction models, with the optimal model dependent on availability of training data and genetic architecture of the trait in question. Linear models were competitive in their performance as per previous work, though the neural network class of predictors was observed to be the most accurate and robust for traits with high heritability. The extent to which non-linear models exploit interaction effects will require further investigation of the causal pathways that lay behind their predictions. Future work utilizing more traits and larger sample sizes, combined with an improved understanding of their respective genetic architectures, may lead to improvements in prediction accuracy.

Iron is an essential mineral that supports numerous biological functions. Studies have reported associations between iron dysregulation and certain cardiovascular and neurodegenerative diseases, but the direction of influence is not clear. Our goal was to use computational approaches to better understand the role of genetically predicted iron levels on disease risk. We meta-analyzed genome-wide association study summary statistics for serum iron levels from two cohorts and two previous meta-analyses. We then obtained summary statistics from 11 neurodegenerative, cerebrovascular, cardiovascular or lipid traits to assess global and regional genetic correlation between iron levels and these traits. We used two-sample Mendelian randomization (MR) to estimate causal effects. Sex-stratified analyses were also carried out to identify effects potentially differing by sex. Overall, we identified three significant global correlations between iron levels and (i) coronary heart disease, (ii) triglycerides, and (iii) high-density lipoprotein (HDL) cholesterol levels. A total of 194 genomic regions had significant (after correction for multiple testing) local correlations between iron levels and the 11 tested traits. MR analysis revealed two potential causal relationships, between genetically predicted iron levels and (i) total cholesterol or (ii) non-HDL cholesterol. Sex-stratified analyses suggested a potential protective effect of iron levels on Parkinson’s disease risk in females, but not in males. Our results will contribute to a better understanding of the genetic basis underlying iron in cardiovascular and neurological health in aging, and to the eventual identification of new preventive interventions or therapeutic avenues for diseases which affect women and men worldwide.

Sex is an important covariate in all genetic and epigenetic research due to its role in the incidence, progression and outcome of many phenotypic characteristics and human diseases. Amyotrophic lateral sclerosis (ALS) is a motor neuron disease with a sex bias towards higher incidence in males. Here, we report for the first time a blood-based epigenome-wide association study meta-analysis in 9274 individuals after stringent quality control (5529 males and 3975 females). We identified a total of 226 ALS saDMPs (sex-associated DMPs) annotated to a total of 159 unique genes. These ALS saDMPs were depleted at transposable elements yet significantly enriched at enhancers and slightly enriched at 3'UTRs. These ALS saDMPs were enriched for transcription factor motifs such as ESR1 and REST. Moreover, we identified an additional 10 genes associated with ALS saDMPs through chromatin loop interactions, suggesting a potential regulatory role for these saDMPs on distant genes. Furthermore, we investigated the relationship between DNA methylation at specific CpG sites and overall survival in ALS using Cox proportional hazards models. We identified two ALS saDMPs, cg14380013 and cg06729676, that showed significant associations with survival. Overall, our study reports a reliable catalogue of sex-associated ALS saDMPs in ALS and elucidates several characteristics of these sites using a large-scale dataset. This resource will benefit future studies aiming to investigate the role of sex in the incidence, progression and risk for ALS.

Significantly more men develop amyotrophic lateral sclerosis (ALS) than women, and heritability is not uniform between male and female transmissions, together suggesting a role for sex in the genetic aetiology of the disease. We therefore performed sex-stratified genome-wide and transcriptome-wide analyses of ALS risk, identifying six novel sex-specific risk loci includingMEF2C, which shows increased expression in female ALS motor neurones. X-chromosome analysis revealed an additional risk locus atIL1RAPL2.

ABSTRACT Objective Genetic variation in the neurofilament heavy chain gene ( NEFH ) has been convincingly linked to the pathogenesis of multiple neurodegenerative diseases, however, the relationship between NEFH mutations and ALS susceptibility has not been robustly explored. We therefore wanted to determine if genetic variants in NEFH modify ALS risk. Methods We performed fixed and random effects model meta-analysis of published case-control studies reporting NEFH variant frequencies using next-generation sequencing, microarray or PCR-based approaches. Comprehensive screening and rare variant burden analysis of NEFH variation in the Project MinE ALS whole-genome sequencing data set was also conducted. Results We identified 12 case-control studies that reported NEFH variant frequencies, for a total of 9,496 samples (4,527 ALS cases and 4,969 controls). Fixed effects meta-analysis found that rare (MAF<1%) missense variants in the tail domain of NEFH increase ALS risk (OR 4.56, 95% CI 2.13-9.72, p<0.0001). A total of 591 rare NEFH variants, mostly novel (78.2%), were found in the Project MinE dataset (8,903 samples: 6,469 cases and 2,434 controls). Burden analysis showed ultra-rare (MAF <0.1%) pathogenic missense variants in the tail domain are associated with ALS (OR 1.94, 95% CI 0.86-4.37, Madsen-Browning p=0.039), replicating and confirming the meta-analysis finding. High-frequency rare (MAF 0.1-1%) tail in-frame deletions also confer susceptibility to ALS (OR 1.18, 95% CI 0.67-2.07, SKAT-O p=0.03), which supports previous findings. Interpretation This study shows that NEFH tail domain variants are a risk factor of ALS and supports the inclusion of missense and in-frame deletion NEFH variants in ALS genetic screening panels.

Background: While frontotemporal involvement is increasingly recognized in Amyotrophic lateral sclerosis (ALS), the degeneration of limbic networks remains poorly characterized, despite growing evidence of amnestic deficits, impaired emotional processing and deficits in social cognition. Methods: A prospective neuroimaging study was conducted with 204 individuals with ALS and 111 healthy controls. Patients were stratified for hexanucleotide expansion status in C9orf72. A deep-learning-based segmentation approach was implemented to segment the nucleus accumbens, hypothalamus, fornix, mammillary body, basal forebrain and septal nuclei. The cortical, subcortical and white matter components of the Papez circuit were also systematically evaluated. Results: Hexanucleotide repeat expansion carriers exhibited bilateral amygdala, hypothalamus and nucleus accumbens atrophy, and C9orf72 negative patients showed bilateral basal forebrain volume reductions compared to controls. Both patient groups showed left rostral anterior cingulate atrophy, left entorhinal cortex thinning and cingulum and fornix alterations, irrespective of the genotype. Fornix, cingulum, posterior cingulate, nucleus accumbens, amygdala and hypothalamus degeneration was more marked in C9orf72-positive ALS patients. Conclusions: Our results highlighted that mesial temporal and parasagittal subcortical degeneration is not unique to C9orf72 carriers. Our radiological findings were consistent with neuropsychological observations and highlighted the importance of comprehensive neuropsychological testing in ALS, irrespective of the underlying genotype.

Repeat expansions in the C9orf72 gene are the most common genetic cause of (ALS) and frontotemporal dementia (FTD). Like other genetic forms of neurodegeneration, pinpointing the precise mechanism(s) by which this mutation leads to neuronal death remains elusive, and this lack of knowledge hampers the development of therapy for C9orf72-related disease. We used an agnostic approach based on genomic data (n = 41,273 ALS and healthy samples, and n = 1,516 C9orf72 carriers) to overcome these bottlenecks. Our drug-repurposing screen, based on gene- and expression-pattern matching and information about the genetic variants influencing onset age among C9orf72 carriers, identified acamprosate, a γ-aminobutyric acid analog, as a potentially repurposable treatment for patients carrying C9orf72 repeat expansions. We validated its neuroprotective effect in cell models and showed comparable efficacy to riluzole, the current standard of care. Our work highlights the potential value of genomics in repurposing drugs in situations where the underlying pathomechanisms are inherently complex. VIDEO ABSTRACT.

Recently, large-scale case-control analyses have been prioritized in the study of ALS. Yet the same effort has not been put forward to investigate additive moderate phenotypic effects of genetic variants in genes driving ALS risk, despite case-level evidence suggesting a potential oligogenic risk model. Considering its direct clinical and therapeutic implications, a large-scale robust investigation of oligogenicity in ALS is greatly needed. Here, we leveraged the Project MinE ALS Sequencing Consortium genome sequencing datasets of individuals with ALS (n = 6711) and controls (n = 2391) to identify signals of association between oligogenicity in known ALS genes (n=26) and disease risk, as well as clinical outcomes. Applying regression models to a discovery and replication cohort, we observed that the risk imparted from carrying rare variants in multiple known ALS genes was significant and was greater than the risk associated with carrying only a single rare variant, both in the presence and absence of variants in the most well-established ALS genes, such as C9orf72 . However, in contrast to risk, the relationships between oligogenicity and ALS clinical outcomes, such as age of onset and survival, might not follow the same pattern as we did not observe any associations. Our findings represent the first large-scale, case-control assessment of oligogenic associations in ALS to date and confirm that oligogenic events involving known ALS risk genes are indeed relevant for the risk of disease in approximately 6% of ALS but not necessarily for disease onset and survival. This must be considered in genetic counselling and testing by ensuring the use of comprehensive gene panels even when a potential pathogenic variant has already been identified. Moreover, in the age of stratified medication and gene therapy, it supports the need of a complete genetic profile for the correct choice of therapy in all ALS patients. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement 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 http://www.neurodegenerationresearch.eu/ [United Kingdom, Medical Research Council (MR/L501529/1 and MR/R024804/1) and Economic and Social Research Council (ES/L008238/1)]. AAC is a NIHR Senior Investigator. AAC receives salary support from the National Institute for Health and Care Research (NIHR) Dementia Biomedical Research Unit at South London and Maudsley NHS Foundation Trust and King's College London. The work leading up to this publication was funded by the European Community's Health Seventh Framework Program (FP7/2007 2013; grant agreement number 259867) and Horizon 2020 Program (H2020-PHC-2014-two-stage; grant agreement number 633413). This project has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 Research and Innovation Programme (grant agreement no. 772376 EScORIAL. This study represents independent research part funded by the NIHR Maudsley Biomedical Research Centre at South London and Maudsley NHS Foundation Trust and King's College London. The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR, King's College London, or the Department of Health and Social Care. AAD is supported by the Canadian Institute of Health Research Banting Postdoctoral Fellowship Program. AI is funded by South London and Maudsley NHS Foundation Trust, MND Scotland, Motor Neurone Disease Association, National Institute for Health and Care Research, Spastic Paraplegia Foundation, Rosetrees Trust, Darby Rimmer MND Foundation, the Medical Research Council (UKRI) and Alzheimer's Research UK. SMKF is supported by grants from ALS Canada, Brain Canada, the Michael J. Fox Foundation, and the Montreal Neurological Institute Hospital. Project MinE Belgium was supported by a grant from IWT (n 140935), the ALS Liga Belgie, the National Lottery of Belgium and the KU Leuven Opening the Future Fund. AAK is funded by the ALS Association Milton Safenowitz Research Fellowship, The Motor Neurone Disease Association (MNDA) Fellowship, The Darby Rimmer Foundation, and The NIHR Maudsley Biomedical Research Centre. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Individual whole-genome sequencing data are available and can be requested through Project MinE (<https://www.projectmine.com/research/data-sharing/>). A data access committee controls access to raw data, ensuring a FAIR data setup (<https://www.datafairport.org>). Details on the frequencies and gene burden test results are available on the ProjectMinE databrowser [29][1] (<http://databrowser.projectmine.com>). [1]: #ref-29