Publications by authors named "Alfredo Iacoangeli"

25 Publications

  • Page 1 of 1

Genomic and phenotypic insights from an atlas of genetic effects on DNA methylation.

Nat Genet 2021 Sep 6;53(9):1311-1321. Epub 2021 Sep 6.

Estonian Genome Center, Institute of Genomics, University of Tartu, Tartu, Estonia.

Characterizing genetic influences on DNA methylation (DNAm) provides an opportunity to understand mechanisms underpinning gene regulation and disease. In the present study, we describe results of DNAm quantitative trait locus (mQTL) analyses on 32,851 participants, identifying genetic variants associated with DNAm at 420,509 DNAm sites in blood. We present a database of >270,000 independent mQTLs, of which 8.5% comprise long-range (trans) associations. Identified mQTL associations explain 15-17% of the additive genetic variance of DNAm. We show that the genetic architecture of DNAm levels is highly polygenic. Using shared genetic control between distal DNAm sites, we constructed networks, identifying 405 discrete genomic communities enriched for genomic annotations and complex traits. Shared genetic variants are associated with both DNAm levels and complex diseases, but only in a minority of cases do these associations reflect causal relationships from DNAm to trait or vice versa, indicating a more complex genotype-phenotype map than previously anticipated.
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http://dx.doi.org/10.1038/s41588-021-00923-xDOI Listing
September 2021

Association of Variants in the SPTLC1 Gene With Juvenile Amyotrophic Lateral Sclerosis.

JAMA Neurol 2021 Aug 30. Epub 2021 Aug 30.

Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom.

Importance: Juvenile amyotrophic lateral sclerosis (ALS) is a rare form of ALS characterized by age of symptom onset less than 25 years and a variable presentation.

Objective: To identify the genetic variants associated with juvenile ALS.

Design, Setting, And Participants: In this multicenter family-based genetic study, trio whole-exome sequencing was performed to identify the disease-associated gene in a case series of unrelated patients diagnosed with juvenile ALS and severe growth retardation. The patients and their family members were enrolled at academic hospitals and a government research facility between March 1, 2016, and March 13, 2020, and were observed until October 1, 2020. Whole-exome sequencing was also performed in a series of patients with juvenile ALS. A total of 66 patients with juvenile ALS and 6258 adult patients with ALS participated in the study. Patients were selected for the study based on their diagnosis, and all eligible participants were enrolled in the study. None of the participants had a family history of neurological disorders, suggesting de novo variants as the underlying genetic mechanism.

Main Outcomes And Measures: De novo variants present only in the index case and not in unaffected family members.

Results: Trio whole-exome sequencing was performed in 3 patients diagnosed with juvenile ALS and their parents. An additional 63 patients with juvenile ALS and 6258 adult patients with ALS were subsequently screened for variants in the SPTLC1 gene. De novo variants in SPTLC1 (p.Ala20Ser in 2 patients and p.Ser331Tyr in 1 patient) were identified in 3 unrelated patients diagnosed with juvenile ALS and failure to thrive. A fourth variant (p.Leu39del) was identified in a patient with juvenile ALS where parental DNA was unavailable. Variants in this gene have been previously shown to be associated with autosomal-dominant hereditary sensory autonomic neuropathy, type 1A, by disrupting an essential enzyme complex in the sphingolipid synthesis pathway.

Conclusions And Relevance: These data broaden the phenotype associated with SPTLC1 and suggest that patients presenting with juvenile ALS should be screened for variants in this gene.
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http://dx.doi.org/10.1001/jamaneurol.2021.2598DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8406220PMC
August 2021

Advances in the genetic classification of amyotrophic lateral sclerosis.

Curr Opin Neurol 2021 Aug 2. Epub 2021 Aug 2.

Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, UK Department of Genetics Center for Genomics and Personalized Medicine, Stanford University School of Medicine, Stanford, California, USA Department of Neurology, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands Maurice Wohl Clinical Neuroscience Institute, Department of Basic and Clinical Neuroscience Department of Biostatistics and Health Informatics, Institute of Psychiatry, Psychology and Neuroscience, King's College London National Institute for Health Research Biomedical Research Centre and Dementia Unit, South London and Maudsley NHS Foundation Trust and King's College London, London, UK.

Purpose Of Review: Amyotrophic lateral sclerosis (ALS) is an archetypal complex disease wherein disease risk and severity are, for the majority of patients, the product of interaction between multiple genetic and environmental factors. We are in a period of unprecedented discovery with new large-scale genome-wide association study (GWAS) and accelerating discovery of risk genes. However, much of the observed heritability of ALS is undiscovered and we are not yet approaching elucidation of the total genetic architecture, which will be necessary for comprehensive disease subclassification.

Recent Findings: We summarize recent developments and discuss the future. New machine learning models will help to address nonlinear genetic interactions. Statistical power for genetic discovery may be boosted by reducing the search-space using cell-specific epigenetic profiles and expanding our scope to include genetically correlated phenotypes. Structural variation, somatic heterogeneity and consideration of environmental modifiers represent significant challenges which will require integration of multiple technologies and a multidisciplinary approach, including clinicians, geneticists and pathologists.

Summary: The move away from fully penetrant Mendelian risk genes necessitates new experimental designs and new standards for validation. The challenges are significant, but the potential reward for successful disease subclassification is large-scale and effective personalized medicine.
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http://dx.doi.org/10.1097/WCO.0000000000000986DOI Listing
August 2021

A HML6 endogenous retrovirus on chromosome 3 is upregulated in amyotrophic lateral sclerosis motor cortex.

Sci Rep 2021 Jul 12;11(1):14283. Epub 2021 Jul 12.

Department of Basic and Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, SE5 9NU, UK.

There is increasing evidence that endogenous retroviruses (ERVs) play a significant role in central nervous system diseases, including amyotrophic lateral sclerosis (ALS). Studies of ALS have consistently identified retroviral enzyme reverse transcriptase activity in patients. Evidence indicates that ERVs are the cause of reverse transcriptase activity in ALS, but it is currently unclear whether this is due to a specific ERV locus or a family of ERVs. We employed a combination of bioinformatic methods to identify whether specific ERVs or ERV families are associated with ALS. Using the largest post-mortem RNA-sequence datasets available we selectively identified ERVs that closely resembled full-length proviruses. In the discovery dataset there was one ERV locus (HML6_3p21.31c) that showed significant increased expression in post-mortem motor cortex tissue after multiple-testing correction. Using six replication post-mortem datasets we found HML6_3p21.31c was consistently upregulated in ALS in motor cortex and cerebellum tissue. In addition, HML6_3p21.31c showed significant co-expression with cytokine binding and genes involved in EBV, HTLV-1 and HIV type-1 infections. There were no significant differences in ERV family expression between ALS and controls. Our results support the hypothesis that specific ERV loci are involved in ALS pathology.
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http://dx.doi.org/10.1038/s41598-021-93742-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8275748PMC
July 2021

DGLinker: flexible knowledge-graph prediction of disease-gene associations.

Nucleic Acids Res 2021 07;49(W1):W153-W161

Department of Biostatistics and Health Informatics, Institute of Psychiatry, Psychology & Neuroscience, King's College London, SE5 8AF, London, UK.

As a result of the advent of high-throughput technologies, there has been rapid progress in our understanding of the genetics underlying biological processes. However, despite such advances, the genetic landscape of human diseases has only marginally been disclosed. Exploiting the present availability of large amounts of biological and phenotypic data, we can use our current understanding of disease genetics to train machine learning models to predict novel genetic factors associated with the disease. To this end, we developed DGLinker, a webserver for the prediction of novel candidate genes for human diseases given a set of known disease genes. DGLinker has a user-friendly interface that allows non-expert users to exploit biomedical information from a wide range of biological and phenotypic databases, and/or to upload their own data, to generate a knowledge-graph and use machine learning to predict new disease-associated genes. The webserver includes tools to explore and interpret the results and generates publication-ready figures. DGLinker is available at https://dglinker.rosalind.kcl.ac.uk. The webserver is free and open to all users without the need for registration.
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http://dx.doi.org/10.1093/nar/gkab449DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8262728PMC
July 2021

Meta-analysis of genome-wide DNA methylation identifies shared associations across neurodegenerative disorders.

Genome Biol 2021 03 26;22(1):90. Epub 2021 Mar 26.

Centre for Clinical Research, The University of Queensland, Brisbane, QLD, 4019, Australia.

Background: People with neurodegenerative disorders show diverse clinical syndromes, genetic heterogeneity, and distinct brain pathological changes, but studies report overlap between these features. DNA methylation (DNAm) provides a way to explore this overlap and heterogeneity as it is determined by the combined effects of genetic variation and the environment. In this study, we aim to identify shared blood DNAm differences between controls and people with Alzheimer's disease, amyotrophic lateral sclerosis, and Parkinson's disease.

Results: We use a mixed-linear model method (MOMENT) that accounts for the effect of (un)known confounders, to test for the association of each DNAm site with each disorder. While only three probes are found to be genome-wide significant in each MOMENT association analysis of amyotrophic lateral sclerosis and Parkinson's disease (and none with Alzheimer's disease), a fixed-effects meta-analysis of the three disorders results in 12 genome-wide significant differentially methylated positions. Predicted immune cell-type proportions are disrupted across all neurodegenerative disorders. Protein inflammatory markers are correlated with profile sum-scores derived from disease-associated immune cell-type proportions in a healthy aging cohort. In contrast, they are not correlated with MOMENT DNAm-derived profile sum-scores, calculated using effect sizes of the 12 differentially methylated positions as weights.

Conclusions: We identify shared differentially methylated positions in whole blood between neurodegenerative disorders that point to shared pathogenic mechanisms. These shared differentially methylated positions may reflect causes or consequences of disease, but they are unlikely to reflect cell-type proportion differences.
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http://dx.doi.org/10.1186/s13059-021-02275-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8004462PMC
March 2021

Cross-reactive probes on Illumina DNA methylation arrays: a large study on ALS shows that a cautionary approach is warranted in interpreting epigenome-wide association studies.

NAR Genom Bioinform 2020 Dec 17;2(4):lqaa105. Epub 2020 Dec 17.

Department of Neurology, UMC Utrecht Brain Center, 3584 CG, Utrecht, the Netherlands.

Illumina DNA methylation arrays are a widely used tool for performing genome-wide DNA methylation analyses. However, measurements obtained from these arrays may be affected by technical artefacts that result in spurious associations if left unchecked. Cross-reactivity represents one of the major challenges, meaning that probes may map to multiple regions in the genome. Although several studies have reported on this issue, few studies have empirically examined the impact of cross-reactivity in an epigenome-wide association study (EWAS). In this paper, we report on cross-reactivity issues that we discovered in a large EWAS on the presence of the repeat expansion in ALS patients. Specifically, we found that that the majority of the significant probes inadvertently cross-hybridized to the locus. Importantly, these probes were not flagged as cross-reactive in previous studies, leading to novel insights into the extent to which cross-reactivity can impact EWAS. Our findings are particularly relevant for epigenetic studies into diseases associated with repeat expansions and other types of structural variation. More generally however, considering that most spurious associations were not excluded based on pre-defined sets of cross-reactive probes, we believe that the presented data-driven flag and consider approach is relevant for any type of EWAS.
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http://dx.doi.org/10.1093/nargab/lqaa105DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7745769PMC
December 2020

Rare Variant Burden Analysis within Enhancers Identifies CAV1 as an ALS Risk Gene.

Cell Rep 2020 12;33(9):108456

Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, UK. Electronic address:

Amyotrophic lateral sclerosis (ALS) is an incurable neurodegenerative disease. CAV1 and CAV2 organize membrane lipid rafts (MLRs) important for cell signaling and neuronal survival, and overexpression of CAV1 ameliorates ALS phenotypes in vivo. Genome-wide association studies localize a large proportion of ALS risk variants within the non-coding genome, but further characterization has been limited by lack of appropriate tools. By designing and applying a pipeline to identify pathogenic genetic variation within enhancer elements responsible for regulating gene expression, we identify disease-associated variation within CAV1/CAV2 enhancers, which replicate in an independent cohort. Discovered enhancer mutations reduce CAV1/CAV2 expression and disrupt MLRs in patient-derived cells, and CRISPR-Cas9 perturbation proximate to a patient mutation is sufficient to reduce CAV1/CAV2 expression in neurons. Additional enrichment of ALS-associated mutations within CAV1 exons positions CAV1 as an ALS risk gene. We propose CAV1/CAV2 overexpression as a personalized medicine target for ALS.
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http://dx.doi.org/10.1016/j.celrep.2020.108456DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7710676PMC
December 2020

Frequency and methylation status of selected retrotransposition competent L1 loci in amyotrophic lateral sclerosis.

Mol Brain 2020 11 13;13(1):154. Epub 2020 Nov 13.

Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK.

Long interspersed element-1 (LINE-1/L1) is the only autonomous transposable element in the human genome that currently mobilises in both germline and somatic tissues. Recent studies have identified correlations between altered retrotransposon expression and the fatal neurodegenerative disease amyotrophic lateral sclerosis (ALS) in a subset of patients. The risk of an individual developing ALS is dependent on an interaction of genetic variants and subsequent modifiers during life. These modifiers could include environmental factors, which can lead to epigenetic and genomic changes, such as somatic mutations, occurring in the neuronal cells that degenerate as the disease develops. There are more than 1 million L1 copies in the human genome today, but only 80-100 L1 loci in the reference genome are considered to be retrotransposition-competent (RC) and an even smaller number of these RC-L1s loci are highly active. We hypothesise that RC-L1s could affect normal cellular function through their mutagenic potential conferred by their ability to retrotranspose in neuronal cells and through DNA damage caused by the endonuclease activity of the L1-encoded ORF2 protein. To investigate whether either an increase in the genomic burden of RC-L1s or epigenetic changes to RC-L1s altering their expression, could play a role in disease development, we chose a set of seven well characterised genomic RC-L1 loci that were reported earlier to be highly active in a cellular L1 retrotransposition reporter assay or serve as major source elements for germline and/or somatic retrotransposition events. Analysis of the insertion allele frequency of five polymorphic RC-L1s, out of the set of seven, for their presence or absence, did not identify an increased number individually or when combined in individuals with the disease. However, we did identify reduced levels of methylation of RC-L1s in the motor cortex of those individuals with both familial and sporadic ALS compared to control brains. The changes to the regulation of the loci encompassing these RC-L1s demonstrated tissue specificity and could be related to the disease process.
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http://dx.doi.org/10.1186/s13041-020-00694-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7666467PMC
November 2020

Genome-wide Meta-analysis Finds the ACSL5-ZDHHC6 Locus Is Associated with ALS and Links Weight Loss to the Disease Genetics.

Cell Rep 2020 10;33(4):108323

Centre for Clinical Research, The University of Queensland, Brisbane QLD, Australia; Department of Neurology, Royal Brisbane and Women's Hospital, Brisbane QLD, Australia; School of Biomedical Sciences, The University of Queensland, Brisbane QLD, Australia.

We meta-analyze amyotrophic lateral sclerosis (ALS) genome-wide association study (GWAS) data of European and Chinese populations (84,694 individuals). We find an additional significant association between rs58854276 spanning ACSL5-ZDHHC6 with ALS (p = 8.3 × 10), with replication in an independent Australian cohort (1,502 individuals; p = 0.037). Moreover, B4GALNT1, G2E3-SCFD1, and TRIP11-ATXN3 are identified using a gene-based analysis. ACSL5 has been associated with rapid weight loss, as has another ALS-associated gene, GPX3. Weight loss is frequent in ALS patients and is associated with shorter survival. We investigate the effect of the ACSL5 and GPX3 single-nucleotide polymorphisms (SNPs), using longitudinal body composition and weight data of 77 patients and 77 controls. In patients' fat-free mass, although not significant, we observe an effect in the expected direction (rs58854276: -2.1 ± 1.3 kg/A allele, p = 0.053; rs3828599: -1.0 ± 1.3 kg/A allele, p = 0.22). No effect was observed in controls. Our findings support the increasing interest in lipid metabolism in ALS and link the disease genetics to weight loss in patients.
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http://dx.doi.org/10.1016/j.celrep.2020.108323DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7610013PMC
October 2020

repeat expansions confer risk for amyotrophic lateral sclerosis and contribute to TDP-43 mislocalization.

Brain Commun 2020 19;2(2):fcaa064. Epub 2020 May 19.

Department of Basic and Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute and United Kingdom Dementia Research Institute, King's College London, London SE5 9NU, UK.

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 , polyglutamine expansions in and polyalanine expansions in . 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 , suggested a similar disease association for the repeat expansion in . We, therefore, performed a large-scale international study in 11 700 individuals, in which we showed a significant association between intermediate repeat expansions and amyotrophic lateral sclerosis (=3.33 × 10). Subsequent functional experiments have shown that ATXN1 reduces the nucleocytoplasmic ratio of TDP-43 and enhances amyotrophic lateral sclerosis phenotypes in , further emphasizing the role of polyglutamine repeat expansions in the pathophysiology of amyotrophic lateral sclerosis.
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http://dx.doi.org/10.1093/braincomms/fcaa064DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7425293PMC
May 2020

Relationship between smoking and ALS: Mendelian randomisation interrogation of causality.

J Neurol Neurosurg Psychiatry 2020 12 26;91(12):1312-1315. Epub 2020 Aug 26.

Maurice Wohl Clinical Neuroscience Institute, Department of Basic and Clinical Neuroscience, King's College London, London, UK

Objective: Smoking has been widely studied as a susceptibility factor for amyotrophic lateral sclerosis (ALS), but results are conflicting and at risk of confounding bias. We used the results of recently published large genome-wide association studies and Mendelian randomisation methods to reduce confounding to assess the relationship between smoking and ALS.

Methods: Two genome-wide association studies investigating lifetime smoking (n=463 003) and ever smoking (n=1 232 091) were identified and used to define instrumental variables for smoking. A genome-wide association study of ALS (20 806 cases; 59 804 controls) was used as the outcome for inverse variance weighted Mendelian randomisation, and four other Mendelian randomisation methods, to test whether smoking is causal for ALS. Analyses were bidirectional to assess reverse causality.

Results: There was no strong evidence for a causal or reverse causal relationship between smoking and ALS. The results of Mendelian randomisation using the inverse variance weighted method were: lifetime smoking OR 0.94 (95% CI 0.74 to 1.19), p value 0.59; ever smoking OR 1.10 (95% CI 1 to 1.23), p value 0.05.

Conclusions: Using multiple methods, large sample sizes and sensitivity analyses, we find no evidence with Mendelian randomisation techniques that smoking causes ALS. Other smoking phenotypes, such as current smoking, may be suitable for future Mendelian randomisation studies.
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http://dx.doi.org/10.1136/jnnp-2020-323316DOI Listing
December 2020

A Knowledge-Based Machine Learning Approach to Gene Prioritisation in Amyotrophic Lateral Sclerosis.

Genes (Basel) 2020 06 19;11(6). Epub 2020 Jun 19.

Department of Biostatistics & Health Informatics, King's College London, 16 De Crespigny Park, London SE5 8AF, UK.

Amyotrophic lateral sclerosis is a neurodegenerative disease of the upper and lower motor neurons resulting in death from neuromuscular respiratory failure, typically within two to five years of first symptoms. Several rare disruptive gene variants have been associated with ALS and are responsible for about 15% of all cases. Although our knowledge of the genetic landscape of this disease is improving, it remains limited. Machine learning models trained on the available protein-protein interaction and phenotype-genotype association data can use our current knowledge of the disease genetics for the prediction of novel candidate genes. Here, we describe a knowledge-based machine learning method for this purpose. We trained our model on protein-protein interaction data from IntAct, gene function annotation from Gene Ontology, and known disease-gene associations from DisGeNet. Using several sets of known ALS genes from public databases and a manual review as input, we generated a list of new candidate genes for each input set. We investigated the relevance of the predicted genes in ALS by using the available summary statistics from the largest ALS genome-wide association study and by performing functional and phenotype enrichment analysis. The predicted sets were enriched for genes associated with other neurodegenerative diseases known to overlap with ALS genetically and phenotypically, as well as for biological processes associated with the disease. Moreover, using ALS genes from ClinVar and our manual review as input, the predicted sets were enriched for ALS-associated genes (ClinVar = 0.038 and manual review = 0.060) when used for gene prioritisation in a genome-wide association study.
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http://dx.doi.org/10.3390/genes11060668DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7349022PMC
June 2020

UK case control study of smoking and risk of amyotrophic lateral sclerosis.

Amyotroph Lateral Scler Frontotemporal Degener 2020 05 17;21(3-4):222-227. Epub 2020 Apr 17.

School of Psychological Science, University of Bristol, Bristol, United Kingdom.

: Susceptibility to amyotrophic lateral sclerosis (ALS) is associated with smoking in some studies, but it is not clear which aspect of smoking behavior is related. Using detailed records of lifetime smoking we investigated the relationship between smoking and ALS in a UK population. : In this retrospective case-control study, smoking status was collected using environmental questionnaires from people diagnosed with ALS between 2008 and 2013 and from age, sex and geographically matched controls. Categorical measures of smoking behavior were: smoking at the time of survey and smoking initiation; continuous measures were intensity (cigarettes per day), duration (years from starting to stopping or time of survey), cigarette pack years, and comprehensive smoking index (CSI), a measure of lifetime smoking. We used logistic regression to assess the risk of ALS with different combinations of smoking variables adjusted for age at survey, gender, level of education, smoking status and alcohol initiation, selecting the best model using the Akaike Information Criterion. : There were 388 records with full smoking history. The best-fitting model used CSI and smoking status at the time of survey. We found a weak association between current smoking and risk of ALS, OR 3.63 (95% CI 1.02-13.9) value 0.05. Increase in CSI score did not increase risk of ALS: OR 0.81 (95% CI 0.58-1.11) value 0.2.: There is weak evidence of a positive effect of current smoking on the risk of ALS which does not show dose-dependence with higher levels of lifetime smoking and maybe a false positive result.
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http://dx.doi.org/10.1080/21678421.2019.1706580DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7261396PMC
May 2020

Exome sequencing in amyotrophic lateral sclerosis implicates a novel gene, DNAJC7, encoding a heat-shock protein.

Nat Neurosci 2019 12 25;22(12):1966-1974. Epub 2019 Nov 25.

Department of Neurology, The Agnes Ginges Center for Human Neurogenetics, Hadassah-Hebrew University Medical Center, Jerusalem, Israel.

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.
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http://dx.doi.org/10.1038/s41593-019-0530-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6919277PMC
December 2019

C9orf72 intermediate expansions of 24-30 repeats are associated with ALS.

Acta Neuropathol Commun 2019 07 17;7(1):115. Epub 2019 Jul 17.

Department of Basic and Clinical Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, UK.

The expansion of a hexanucleotide repeat GGGGCC in C9orf72 is the most common known cause of ALS accounting for ~ 40% familial cases and ~ 7% sporadic cases in the European population. In most people, the repeat length is 2, but in people with ALS, hundreds to thousands of repeats may be observed. A small proportion of people have an intermediate expansion, of the order of 20 to 30 repeats in size, and it remains unknown whether intermediate expansions confer risk of ALS in the same way that massive expansions do. We investigated the association of this intermediate repeat with ALS by performing a meta-analysis of four previously published studies and a new British/Alzheimer's Disease Neuroimaging Initiative dataset of 1295 cases and 613 controls. The final dataset comprised 5071 cases and 3747 controls. Our meta-analysis showed association between ALS and intermediate C9orf72 repeats of 24 to 30 repeats in size (random-effects model OR = 4.2, 95% CI = 1.23-14.35, p-value = 0.02). Furthermore, we showed a different frequency of the repeat between the northern and southern European populations (Fisher's exact test p-value = 5 × 10). Our findings provide evidence for the association between intermediate repeats and ALS (p-value = 2 × 10) with direct relevance for research and clinical practice by showing that an expansion of 24 or more repeats should be considered pathogenic.
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http://dx.doi.org/10.1186/s40478-019-0724-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6637621PMC
July 2019

Telomere length is greater in ALS than in controls: a whole genome sequencing study.

Amyotroph Lateral Scler Frontotemporal Degener 2019 05 1;20(3-4):229-234. Epub 2019 Apr 1.

a Department of Basic and Clinical Neuroscience , King's College London, Maurice Wohl Clinical Neuroscience Institute , London , UK.

Amyotrophic lateral sclerosis is a neurodegenerative disease of motor neurons resulting in progressive paralysis and death, typically within 3-5 years. Although the heritability of ALS is about 60%, only about 11% is explained by common gene variants, suggesting that other forms of genetic variation are important. Telomeres maintain DNA integrity during cellular replication and shorten naturally with age. Gender and age are risk factors for ALS and also associated with telomere length. We therefore investigated telomere length in ALS. We estimated telomere length by applying a bioinformatics analysis to whole genome sequence data of leukocyte-derived DNA from people with ALS and age and gender-matched matched controls in a UK population. We tested the association of telomere length with ALS and ALS survival. There were 1241 people with ALS and 335 controls. The median age for ALS was 62.5 years and for controls, 60.1 years, with a male-female ratio of 62:38. Accounting for age and sex, there was a 9% increase of telomere length in ALS compared to matched controls. Those with longer telomeres had a 16% increase in median survival. Of nine SNPs associated with telomere length, two were also associated with ALS: rs8105767 near the gene ( = 1.29 × 10) and rs6772228 ( = 0.001), which is in an intron for the gene. Longer telomeres in leukocyte-derived DNA are associated with ALS, and with increased survival in those with ALS.
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http://dx.doi.org/10.1080/21678421.2019.1586951DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6567548PMC
May 2019

ALSgeneScanner: a pipeline for the analysis and interpretation of DNA sequencing data of ALS patients.

Amyotroph Lateral Scler Frontotemporal Degener 2019 05 5;20(3-4):207-215. Epub 2019 Mar 5.

c UK Dementia Research Institute, King's College London , London , UK.

Amyotrophic lateral sclerosis (ALS, MND) is a neurodegenerative disease of upper and lower motor neurons resulting in death from neuromuscular respiratory failure, typically within two years of first symptoms. Genetic factors are an important cause of ALS, with variants in more than 25 genes having strong evidence, and weaker evidence available for variants in more than 120 genes. With the increasing availability of next-generation sequencing data, non-specialists, including health care professionals and patients, are obtaining their genomic information without a corresponding ability to analyze and interpret it. Furthermore, the relevance of novel or existing variants in ALS genes is not always apparent. Here we present ALSgeneScanner, a tool that is easy to install and use, able to provide an automatic, detailed, annotated report, on a list of ALS genes from whole-genome sequencing (WGS) data in a few hours and whole exome sequence data in about 1 h on a readily available mid-range computer. This will be of value to non-specialists and aid in the interpretation of the relevance of novel and existing variants identified in DNA sequencing data.
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http://dx.doi.org/10.1080/21678421.2018.1562553DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6567555PMC
May 2019

Association of NIPA1 repeat expansions with amyotrophic lateral sclerosis in a large international cohort.

Neurobiol Aging 2019 02 22;74:234.e9-234.e15. Epub 2018 Sep 22.

Department of Neurology, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, the Netherlands. Electronic address:

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). Together with previous reports, these findings provide evidence for an association of an expanded polyalanine repeat in NIPA1 and ALS.
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http://dx.doi.org/10.1016/j.neurobiolaging.2018.09.012DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7893598PMC
February 2019

Younger age of onset in familial amyotrophic lateral sclerosis is a result of pathogenic gene variants, rather than ascertainment bias.

J Neurol Neurosurg Psychiatry 2019 03 30;90(3):268-271. Epub 2018 Sep 30.

Department of Basic and Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute, King's College London, London, UK

Objective: Amyotrophic lateral sclerosis (ALS) is a rapidly progressive neurodegenerative disease of motor neurons with a median survival of 2 years. Familial ALS has a younger age of onset than apparently sporadic ALS. We sought to determine whether this younger age of onset is a result of ascertainment bias or has a genetic basis.

Methods: Samples from people with ALS were sequenced for 13 ALS genes. To determine the effect of genetic variation, age of onset was compared in people with sporadic ALS carrying a pathogenic gene variant and those who do not; to determine the effect of family history, we compared those with genetic sporadic ALS and familial ALS.

Results: There were 941 people with a diagnosis of ALS, 100 with familial ALS. Of 841 with apparently sporadic ALS, 95 carried a pathogenic gene variant. The mean age of onset in familial ALS was 5.3 years younger than for apparently sporadic ALS (p=6.0×10, 95% CI 2.8 to 7.8 years). The mean age of onset of genetic sporadic ALS was 2.9 years younger than non-genetic sporadic ALS (p=0.011, 95% CI 0.7 to 5.2 years). There was no difference between the mean age of onset in genetic sporadic ALS and familial ALS (p=0.097).

Conclusions: People with familial ALS have an age of onset about 5 years younger than those with apparently sporadic ALS, and we have shown that this is a result of Mendelian gene variants lowering the age of onset, rather than ascertainment bias.
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http://dx.doi.org/10.1136/jnnp-2018-319089DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6518463PMC
March 2019

PepComposer: computational design of peptides binding to a given protein surface.

Nucleic Acids Res 2016 07 30;44(W1):W522-8. Epub 2016 Apr 30.

Department of Physics, Sapienza University, Piazzale Aldo Moro, 5-00184 Rome, Italy Istituto Pasteur-Fondazione Cenci Bolognetti, Viale Regina Elena 291, 00161 Rome, Italy.

There is a wide interest in designing peptides able to bind to a specific region of a protein with the aim of interfering with a known interaction or as starting point for the design of inhibitors. Here we describe PepComposer, a new pipeline for the computational design of peptides binding to a given protein surface. PepComposer only requires the target protein structure and an approximate definition of the binding site as input. We first retrieve a set of peptide backbone scaffolds from monomeric proteins that harbor the same backbone arrangement as the binding site of the protein of interest. Next, we design optimal sequences for the identified peptide scaffolds. The method is fully automatic and available as a web server at http://biocomputing.it/pepcomposer/webserver.
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http://dx.doi.org/10.1093/nar/gkw366DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4987918PMC
July 2016

Exploiting homology information in nontemplate based prediction of protein structures.

J Chem Theory Comput 2015 Oct 30;11(10):5045-51. Epub 2015 Sep 30.

Department of Physics, Sapienza University of Rome , P.le A. Moro 4, 00185 Rome, Italy.

In this paper we describe a novel strategy for exploring the conformational space of proteins and show that this leads to better models for proteins the structure of which is not amenable to template based methods. Our strategy is based on the assumption that the energy global minimum of homologous proteins must correspond to similar conformations, while the precise profiles of their energy landscape, and consequently the positions of the local minima, are likely to be different. In line with this hypothesis, we apply a replica exchange Monte Carlo simulation protocol that, rather than using different parameters for each parallel simulation, uses the sequences of homologous proteins. We show that our results are competitive with respect to alternative methods, including those producing the best model for each of the analyzed targets in the CASP10 (10th Critical Assessment of techniques for protein Structure Prediction) experiment free modeling category.
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http://dx.doi.org/10.1021/acs.jctc.5b00371DOI Listing
October 2015
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