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1.  HFE p.H63D polymorphism does not influence ALS phenotype and survival 
Neurobiology of aging  2015;36(10):2906.e7-2906.11.
It has been recently reported that the p.His63Asp polymorphism of the HFE gene accelerates disease progression both in the SOD1 transgenic mouse and in amyotrophic lateral sclerosis (ALS) patients. We have evaluated the effect of HFE p.His63Asp polymorphism on the phenotype in 1351 Italian ALS patients (232 of Sardinian ancestry). Patients were genotyped for the HFE p.His63Asp polymorphism (CC, GC, and GG). All patients were also assessed for C9ORF72, TARDBP, SOD1, and FUS mutations. Of the 1351 ALS patients, 363 (29.2%) were heterozygous (GC) for the p.His63Asp polymorphism and 30 (2.2%) were homozygous for the minor allele (GG). Patients with CC, GC, and GG polymorphisms did not significantly differ by age at onset, site of onset of symptoms, and survival; however, in SOD1 patients with CG or GG polymorphism had a significantly longer survival than those with a CC polymorphism. Differently from what observed in the mouse model of ALS, the HFE p.His63Asp polymorphism has no effect on ALS phenotype in this large series of Italian ALS patients.
doi:10.1016/j.neurobiolaging.2015.06.016
PMCID: PMC5183653  PMID: 26174855
Amyotrophic lateral sclerosis; HFE polymorphisms; phenotype; survival; SOD1
2.  Motor neuron disease in 2014: Biomarkers for ALS—in search of the Promised Land 
Nature reviews. Neurology  2014;11(2):72-74.
The past year has seen some extraordinary activity in clinical amyotrophic lateral sclerosis (ALS) research. Two trials were completed, with negative results, but the discovery of novel ALS-associated genes, and body fluid and imaging biomarkers warrants cautious optimism. Here, we provide a snapshot of some of the main findings in 2014.
doi:10.1038/nrneurol.2014.250
PMCID: PMC5185468  PMID: 25534912
3.  Molecular Chaperones in the Pathogenesis of Amyotrophic Lateral Sclerosis: The Role of HSPB1 
Human Mutation  2016;37(11):1202-1208.
ABSTRACT
Genetic discoveries in amyotrophic lateral sclerosis (ALS) have a significant impact on deciphering molecular mechanisms of motor neuron degeneration but, despite recent advances, the etiology of most sporadic cases remains elusive. Several cellular mechanisms contribute to the motor neuron degeneration in ALS, including RNA metabolism, cellular interactions between neurons and nonneuronal cells, and seeding of misfolded protein with prion‐like propagation. In this scenario, the importance of protein turnover and degradation in motor neuron homeostasis gained increased recognition. In this study, we evaluated the role of the candidate gene HSPB1, a molecular chaperone involved in several proteome‐maintenance functions. In a cohort of 247 unrelated Italian ALS patients, we identified two variants (c.570G>C, p.Gln190His and c.610dupG, p.Ala204Glyfs*6). Functional characterization of the p.Ala204Glyfs*6 demonstrated that the mutant protein alters HSPB1 dynamic equilibrium, sequestering the wild‐type protein in a stable dimer and resulting in a loss of chaperone‐like activity. Our results underline the relevance of identifying rare but pathogenic variations in sporadic neurodegenerative diseases, suggesting a possible correlation between specific pathomechanisms linked to HSPB1 mutations and the associated neurological phenotype. Our study provides additional lines of evidence to support the involvement of HSPB1 in the pathogenesis of sporadic ALS.
doi:10.1002/humu.23062
PMCID: PMC5108433  PMID: 27492805
sALS; HSPB1; chaperone activity; molecular modelling
4.  Projected increase in amyotrophic lateral sclerosis from 2015 to 2040 
Nature Communications  2016;7:12408.
Although amyotrophic lateral sclerosis (ALS) is relatively rare, the socioeconomic significance of the disease is extensive. It is therefore vital to project the epidemiologic trend of ALS. To date, there have been few published studies attempting to estimate the number and distribution of ALS cases in the upcoming years. Here we show that the number of ALS cases across the globe will increase from 222,801 in 2015 to 376,674 in 2040, representing an increase of 69%. This increase is predominantly due to ageing of the population, particularly among developing nations. This projection is likely an underestimate due to improving healthcare and economic conditions. The results should be used to inform healthcare policy to more efficiently allocate healthcare resources.
The socioeconomic burden of amyotrophic lateral sclerosis (ALS) is high, but the projected number of cases in the upcoming years is unclear. Here, the authors estimate the number and distribution of ALS cases to 2040, and show that cases are projected to increase, particularly in developing nations.
doi:10.1038/ncomms12408
PMCID: PMC4987527  PMID: 27510634
5.  A PET/CT approach to spinal cord metabolism in amyotrophic lateral sclerosis 
Purpose
In amyotrophic lateral sclerosis, functional alterations within the brain have been intensively assessed, while progression of lower motor neuron damage has scarcely been defined. The aim of the present study was to develop a computational method to systematically evaluate spinal cord metabolism as a tool to monitor disease mechanisms.
Methods
A new computational three-dimensional method to extract the spinal cord from 18F-FDG PET/CT images was evaluated in 30 patients with spinal onset amyotrophic lateral sclerosis and 30 controls. The algorithm identified the skeleton on the CT images by using an extension of the Hough transform and then extracted the spinal canal and the spinal cord. In these regions, 18F-FDG standardized uptake values were measured to estimate the metabolic activity of the spinal canal and cord. Measurements were performed in the cervical and dorsal spine and normalized to the corresponding value in the liver.
Results
Uptake of 18F-FDG in the spinal cord was significantly higher in patients than in controls (p < 0.05). By contrast, no significant differences were observed in spinal cord and spinal canal volumes between the two groups. 18F-FDG uptake was completely independent of age, gender, degree of functional impairment, disease duration and riluzole treatment. Kaplan-Meier analysis showed a higher mortality rate in patients with standardized uptake values above the fifth decile at the 3-year follow-up evaluation (log-rank test, p < 0.01). The independence of this value was confirmed by multivariate Cox analysis.
Conclusion
Our computational three-dimensional method enabled the evaluation of spinal cord metabolism and volume and might represent a potential new window onto the pathophysiology of amyotrophic lateral sclerosis.
doi:10.1007/s00259-016-3440-3
PMCID: PMC5007279  PMID: 27421971
PET/CT; Amyotrophic lateral sclerosis; Spinal cord; Neuroimaging
6.  A Genome-wide Association Study of Myasthenia Gravis 
JAMA neurology  2015;72(4):396-404.
IMPORTANCE
Myasthenia gravis is a chronic, autoimmune, neuromuscular disease characterized by fluctuating weakness of voluntary muscle groups. Although genetic factors are known to play a role in this neuroimmunological condition, the genetic etiology underlying myasthenia gravis is not well understood.
OBJECTIVE
To identify genetic variants that alter susceptibility to myasthenia gravis, we performed a genome-wide association study.
DESIGN, SETTING, AND PARTICIPANTS
DNA was obtained from 1032 white individuals from North America diagnosed as having acetylcholine receptor antibody–positive myasthenia gravis and 1998 race/ethnicity-matched control individuals from January 2010 to January 2011. These samples were genotyped on Illumina OmniExpress single-nucleotide polymorphism arrays. An independent cohort of 423 Italian cases and 467 Italian control individuals were used for replication.
MAIN OUTCOMES AND MEASURES
We calculated P values for association between 8114394 genotyped and imputed variants across the genome and risk for developing myasthenia gravis using logistic regression modeling. A threshold P value of 5.0 × 10−8 was set for genome-wide significance after Bonferroni correction for multiple testing.
RESULTS
In the over all case-control cohort, we identified association signals at CTLA4 (rs231770; P = 3.98 × 10−8; odds ratio, 1.37; 95% CI, 1.25–1.49), HLA-DQA1 (rs9271871; P = 1.08 × 10−8; odds ratio, 2.31; 95% CI, 2.02 – 2.60), and TNFRSF11A (rs4263037; P = 1.60 × 10−9; odds ratio, 1.41; 95% CI, 1.29–1.53). These findings replicated for CTLA4 and HLA-DQA1 in an independent cohort of Italian cases and control individuals. Further analysis revealed distinct, but overlapping, disease-associated loci for early- and late-onset forms of myasthenia gravis. In the late-onset cases, we identified 2 association peaks: one was located in TNFRSF11A (rs4263037; P = 1.32 × 10−12; odds ratio, 1.56; 95% CI, 1.44–1.68) and the other was detected in the major histocompatibility complex on chromosome 6p21 (HLA-DQA1; rs9271871; P = 7.02 × 10−18; odds ratio, 4.27; 95% CI, 3.92–4.62). Association within the major histocompatibility complex region was also observed in early-onset cases (HLA-DQA1; rs601006; P = 2.52 × 10−11; odds ratio, 4.0; 95% CI, 3.57–4.43), although the set of single-nucleotide polymorphisms was different from that implicated among late-onset cases.
CONCLUSIONS AND RELEVANCE
Our genetic data provide insights into aberrant cellular mechanisms responsible for this prototypical autoimmune disorder. They also suggest that clinical trials of immunomodulatory drugs related to CTLA4 and that are already Food and Drug Administration approved as therapies for other autoimmune diseases could be considered for patients with refractory disease.
doi:10.1001/jamaneurol.2014.4103
PMCID: PMC4856525  PMID: 25643325
7.  CHCH10 mutations in an Italian cohort of familial and sporadic ALS patients 
Neurobiology of aging  2015;36(4):1767.e3-1767.e6.
Mutations in CHCHD10 have recently been described as a cause of frontotemporal dementia (FTD) co-morbid with amyotrophic lateral sclerosis (ALS). The aim of this study was to assess the frequency and clinical characteristics of CHCHD10 mutations in Italian patients diagnosed with familial (n = 64) and apparently sporadic ALS (n = 224). Three apparently sporadic patients were found to carry c.100C>T (p.Pro34Ser) heterozygous variant in the exon 2 of CHCHD10. This mutation had been previously described in two unrelated French patients with FTD-ALS. However, our patients had a typical ALS, without evidence of FTD, cerebellar or extrapyramidal signs, or sensorineural deficits. We confirm that CHCHD10 mutations account for ∼1% of Italian ALS patients and are a cause of disease in subject without dementia or other atypical clinical signs.
doi:10.1016/j.neurobiolaging.2015.01.017
PMCID: PMC4380794  PMID: 25726362
9.  Genetic architecture of ALS in Sardinia 
Neurobiology of aging  2014;35(12):2882.e7-2882.e12.
Conserved populations, such as Sardinians, displaying elevated rates of familial or sporadic ALS provide unique information on the genetics of the disease. Our aim was to describe the genetic profile of a consecutive series of ALS patients of Sardinian ancestry. All ALS patients of Sardinian ancestry, identified between 2008 and 2013 through the ITALSGEN consortium, were eligible to be included in the study. Patients and controls underwent the analysis of TARDBP, C9ORF72, SOD1, and FUS genes. Genetic mutations were identified in 155 out of 375 Sardinian ALS cases (41.3%), more commonly the p.A382T and p.G295S mutations of TARDBP, and the GGGGCC hexanucleotide repeat expansion of C9ORF72. One patient had both p.G295S and p.A382T mutation of TARDBP and eight carried both the heterozygous p.A382T mutation of TARDBP and a repeat expansion of C9ORF72. Patients carrying the p.A382T and the p.G295S mutations of TARDBP and the C9ORF72 repeat expansion shared distinct haplotypes across these loci. Patients with co-occurrence of C9ORF72 and TARDBP p.A382T missense mutation had a significantly lower age at onset and shorter survival. More than 40% of all cases on the island of Sardinia carry a mutation of an ALS-related gene, representing the highest percentage of ALS cases genetically explained outside of Scandinavia. Clinical phenotypes associated with different genetic mutations show some distinctive characteristics, but the heterogeneity between and among families carrying the same mutations implies that ALS manifestation is influenced by other genetic and non-genetic factors.
doi:10.1016/j.neurobiolaging.2014.07.012
PMCID: PMC4252367  PMID: 25123918
Amyotrophic Lateral Sclerosis; Sardinia; phenotype; genetics; penetrance; prognosis
10.  ALS/FTD phenotype in two Sardinian families carrying both C9ORF72 and TARDBP mutations 
Background
In the isolated population of Sardinia, a Mediterranean island, ~25% of ALS cases carry either a p.A382T mutation of the TARDBP gene or a GGGGCC hexanucleotide repeat expansion in the first intron of the C9ORF72 gene.
Objective
To describe the co-presence of two genetic mutations in two Sardinian ALS patients.
Methods
We identified two index ALS cases carrying both the p.A382T missense mutation of TARDBP gene and the hexanucleotide repeat expansion of C9ORF72 gene.
Results
The index case of Family A had bulbar ALS and frontemporal dementia (FTD) at 43. His father, who carried the hexanucleotide repeat expansion of C9ORF72 gene, had spinal ALS and FTD at 64 and his mother, who carried the TARDBP gene p.A382T missense mutation, had spinal ALS and FTD at 69. The index case of Family B developed spinal ALS without FTD at 35 and had a rapid course to respiratory failure. His parents are healthy at 62 and 63. The two patients share the known founder risk haplotypes across both the C9ORF72 9p21 locus and the TARDBP 1p36.22 locus.
Conclusions
Our data show that in rare neurodegenerative causing genes can co-exist within the same individuals and are associated with a more severe disease course.
doi:10.1136/jnnp-2012-302219
PMCID: PMC4568835  PMID: 22550220
11.  Genome-Wide Analysis of the Heritability of Amyotrophic Lateral Sclerosis 
JAMA neurology  2014;71(9):1123-1134.
Importance
Considerable advances have been made in our understanding of the genetics underlying amyotrophic lateral sclerosis (ALS). Nevertheless, for the majority of patients who receive a diagnosis of ALS, the role played by genetics is unclear. Further elucidation of the genetic architecture of this disease will help clarify the role of genetic variation in ALS populations.
Objective
To estimate the relative importance of genetic factors in a complex disease such as ALS by accurately quantifying heritability using genome-wide data derived from genome-wide association studies.
Design, Setting, and Participants
We applied the genome-wide complex trait analysis algorithm to 3 genome-wide association study data sets that were generated from ALS case-control cohorts of European ancestry to estimate the heritability of ALS. Cumulatively, these data sets contained genotype data from 1223 cases and 1591 controls that had been previously generated and are publically available on the National Center for Biotechnology Information database of genotypes and phenotypes website (http://www.ncbi.nlm.nih.gov/gap). The cohorts genotyped as part of these genome-wide association study efforts include the InCHIANTI (aging in the Chianti area) Study, the Piemonte and Valle d’Aosta Register for Amyotrophic Lateral Sclerosis, the National Institute of Neurological Disorders and Stroke Repository, and an ALS specialty clinic in Helsinki, Finland.
Main Outcomes and Measures
A linear mixed model was used to account for all known single-nucleotide polymorphisms simultaneously and to quantify the phenotypic variance present in ostensibly outbred individuals. Variance measures were used to estimate heritability.
Results
With our meta-analysis, which is based on genome-wide genotyping data, we estimated the overall heritability of ALS to be approximately 21.0% (95% CI, 17.1–24.9) (SE = 2.0%), indicating that additional genetic variation influencing risk of ALS loci remains to be identified. Furthermore, we identified 17 regions of the genome that display significantly high heritability estimates. Eleven of these regions represent novel candidate regions for ALS risk.
Conclusions and Relevance
We found the heritability of ALS to be significantly higher than previously reported. We also identified multiple, novel genomic regions that we hypothesize may contain causative risk variants that influence susceptibility to ALS.
doi:10.1001/jamaneurol.2014.1184
PMCID: PMC4566960  PMID: 25023141
12.  State of play in amyotrophic lateral sclerosis genetics 
Nature neuroscience  2013;17(1):17-23.
doi:10.1038/nn.3584
PMCID: PMC4544832  PMID: 24369373
13.  Erythropoietin in amyotrophic lateral sclerosis: a multicentre, randomised, double blind, placebo controlled, phase III study 
Objective
To assess the efficacy of recombinant human erythropoietin (rhEPO) in amyotrophic lateral sclerosis (ALS).
Methods
Patients with probable laboratory-supported, probable or definite ALS were enrolled by 25 Italian centres and randomly assigned (1:1) to receive intravenous rhEPO 40 000 IU or placebo fortnightly as add-on treatment to riluzole 100 mg daily for 12 months. The primary composite outcome was survival, tracheotomy or >23 h non-invasive ventilation (NIV). Secondary outcomes were ALSFRS-R, slow vital capacity (sVC) and quality of life (ALSAQ-40) decline. Tolerability was evaluated analysing adverse events (AEs) causing withdrawal. The randomisation sequence was computer-generated by blocks, stratified by centre, disease severity (ALSFRS-R cut-off score of 33) and onset (spinal or bulbar). The main outcome analysis was performed in all randomised patients and by intention-to-treat for the entire population and patients stratified by severity and onset. The study is registered, EudraCT 2009-016066-91.
Results
We randomly assigned 208 patients, of whom 5 (1 rhEPO and 4 placebo) withdrew consent and 3 (placebo) became ineligible (retinal thrombosis, respiratory insufficiency, SOD1 mutation) before receiving treatment; 103 receiving rhEPO and 97 placebo were eligible for analysis. At 12 months, the annualised rate of death (rhEPO 0.11, 95% CI 0.06 to 0.20; placebo: 0.08, CI 0.04 to 0.17), tracheotomy or >23 h NIV (rhEPO 0.16, CI 0.10 to 0.27; placebo 0.18, CI 0.11 to 0.30) did not differ between groups, also after stratification by onset and ALSFRS-R at baseline. Withdrawal due to AE was 16.5% in rhEPO and 8.3% in placebo. No differences were found for secondary outcomes.
Conclusions
RhEPO 40 000 IU fortnightly did not change the course of ALS.
doi:10.1136/jnnp-2014-308996
PMCID: PMC4515982  PMID: 25595151
ALS; MOTOR NEURON DISEASE
14.  C9orf72 and UNC13A are shared risk loci for ALS and FTD: a genome-wide meta-analysis 
Annals of neurology  2014;76(1):120-133.
Objective
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.
Methods
We used published GWAS data of 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.
Results
Meta-analysis identified 19 genome-wide significant single nucleotide polymorphisms (SNPs) at C9orf72 on chromosome 9p21.2 (lowest p=2.6×10−12) and one 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).
Interpretation
We identified common genetic variants at 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.
doi:10.1002/ana.24198
PMCID: PMC4137231  PMID: 24931836
15.  ALS mutant FUS proteins are recruited into stress granules in induced pluripotent stem cell-derived motoneurons 
Disease Models & Mechanisms  2015;8(7):755-766.
ABSTRACT
Patient-derived induced pluripotent stem cells (iPSCs) provide an opportunity to study human diseases mainly in those cases for which no suitable model systems are available. Here, we have taken advantage of in vitro iPSCs derived from patients affected by amyotrophic lateral sclerosis (ALS) and carrying mutations in the RNA-binding protein FUS to study the cellular behavior of the mutant proteins in the appropriate genetic background. Moreover, the ability to differentiate iPSCs into spinal cord neural cells provides an in vitro model mimicking the physiological conditions. iPSCs were derived from FUSR514S and FUSR521C patient fibroblasts, whereas in the case of the severe FUSP525L mutation, in which fibroblasts were not available, a heterozygous and a homozygous iPSC line were raised by TALEN-directed mutagenesis. We show that aberrant localization and recruitment of FUS into stress granules (SGs) is a prerogative of the FUS mutant proteins and occurs only upon induction of stress in both undifferentiated iPSCs and spinal cord neural cells. Moreover, we show that the incorporation into SGs is proportional to the amount of cytoplasmic FUS, strongly correlating with the cytoplasmic delocalization phenotype of the different mutants. Therefore, the available iPSCs represent a very powerful system for understanding the correlation between FUS mutations, the molecular mechanisms of SG formation and ALS ethiopathogenesis.
Summary: Mutated FUS protein is aberrantly delocalized and recruited into stress granules in iPSC-derived motoneurons, which provide a new model system for amyotrophic lateral sclerosis.
doi:10.1242/dmm.020099
PMCID: PMC4486861  PMID: 26035390
ALS; FUS; TALE nucleases; iPSCs
16.  A de novo nonsense mutation of the FUS gene in an apparently familial ALS case 
Neurobiology of aging  2013;35(6):1513.e7-1513.e11.
Mutations in C9ORF72, SOD1, TARDBP and FUS genes account for approximately two third of familial cases and 5% of sporadic amyotrophic lateral sclerosis (ALS) cases. We present the first case of an ALS patient carrying a de novo nonsense mutation in exon 14 of the FUS gene (c.1483c>t; p.R495X) in a young patient with an apparently familial ALS. This mutation cause a phenotype characterized by a young age at onset, a rapid course (<24 months) and a bulbar onset with early respiratory involvement with a predominant lower motor neuron disease. De novo mutations could account for a sizable number of apparently sporadic ALS patients carrying mutations of ALS-related genes.
doi:10.1016/j.neurobiolaging.2013.12.028
PMCID: PMC3961545  PMID: 24439481
17.  A genome-wide association meta-analysis identifies a novel locus at 17q11.2 associated with sporadic amyotrophic lateral sclerosis 
Fogh, Isabella | Ratti, Antonia | Gellera, Cinzia | Lin, Kuang | Tiloca, Cinzia | Moskvina, Valentina | Corrado, Lucia | Sorarù, Gianni | Cereda, Cristina | Corti, Stefania | Gentilini, Davide | Calini, Daniela | Castellotti, Barbara | Mazzini, Letizia | Querin, Giorgia | Gagliardi, Stella | Del Bo, Roberto | Conforti, Francesca L. | Siciliano, Gabriele | Inghilleri, Maurizio | Saccà, Francesco | Bongioanni, Paolo | Penco, Silvana | Corbo, Massimo | Sorbi, Sandro | Filosto, Massimiliano | Ferlini, Alessandra | Di Blasio, Anna M. | Signorini, Stefano | Shatunov, Aleksey | Jones, Ashley | Shaw, Pamela J. | Morrison, Karen E. | Farmer, Anne E. | Van Damme, Philip | Robberecht, Wim | Chiò, Adriano | Traynor, Bryan J. | Sendtner, Michael | Melki, Judith | Meininger, Vincent | Hardiman, Orla | Andersen, Peter M. | Leigh, Nigel P. | Glass, Jonathan D. | Overste, Daniel | Diekstra, Frank P. | Veldink, Jan H. | van Es, Michael A. | Shaw, Christopher E. | Weale, Michael E. | Lewis, Cathryn M. | Williams, Julie | Brown, Robert H. | Landers, John E. | Ticozzi, Nicola | Ceroni, Mauro | Pegoraro, Elena | Comi, Giacomo P. | D'Alfonso, Sandra | van den Berg, Leonard H. | Taroni, Franco | Al-Chalabi, Ammar | Powell, John | Silani, Vincenzo | Brescia Morra, Vincenzo | Filla, Alessandro | Massimo, Filosto | Marsili, Angela | Viviana, Pensato | Puorro, Giorgia | La Bella, Vincenzo | Logroscino, Giancarlo | Monsurrò, Maria Rosaria | Quattrone, Aldo | Simone, Isabella Laura | Ahmeti, Kreshnik B. | Ajroud-Driss, Senda | Armstrong, Jennifer | Birve, Anne | Blauw, Hylke M. | Bruijn, Lucie | Chen, Wenjie | Comeau, Mary C. | Cronin, Simon | Soraya, Gkazi Athina | Grab, Josh D. | Groen, Ewout J. | Haines, Jonathan L. | Heller, Scott | Huang, Jie | Hung, Wu-Yen | Jaworski, James M. | Khan, Humaira | Langefeld, Carl D. | Marion, Miranda C. | McLaughlin, Russell L. | Miller, Jack W. | Mora, Gabriele | Pericak-Vance, Margaret A. | Rampersaud, Evadnie | Siddique, Nailah | Siddique, Teepu | Smith, Bradley N. | Sufit, Robert | Topp, Simon | Vance, Caroline | van Vught, Paul | Yang, Yi | Zheng, J.G.
Human Molecular Genetics  2013;23(8):2220-2231.
Identification of mutations at familial loci for amyotrophic lateral sclerosis (ALS) has provided novel insights into the aetiology of this rapidly progressing fatal neurodegenerative disease. However, genome-wide association studies (GWAS) of the more common (∼90%) sporadic form have been less successful with the exception of the replicated locus at 9p21.2. To identify new loci associated with disease susceptibility, we have established the largest association study in ALS to date and undertaken a GWAS meta-analytical study combining 3959 newly genotyped Italian individuals (1982 cases and 1977 controls) collected by SLAGEN (Italian Consortium for the Genetics of ALS) together with samples from Netherlands, USA, UK, Sweden, Belgium, France, Ireland and Italy collected by ALSGEN (the International Consortium on Amyotrophic Lateral Sclerosis Genetics). We analysed a total of 13 225 individuals, 6100 cases and 7125 controls for almost 7 million single-nucleotide polymorphisms (SNPs). We identified a novel locus with genome-wide significance at 17q11.2 (rs34517613 with P = 1.11 × 10−8; OR 0.82) that was validated when combined with genotype data from a replication cohort (P = 8.62 × 10−9; OR 0.833) of 4656 individuals. Furthermore, we confirmed the previously reported association at 9p21.2 (rs3849943 with P = 7.69 × 10−9; OR 1.16). Finally, we estimated the contribution of common variation to heritability of sporadic ALS as ∼12% using a linear mixed model accounting for all SNPs. Our results provide an insight into the genetic structure of sporadic ALS, confirming that common variation contributes to risk and that sufficiently powered studies can identify novel susceptibility loci.
doi:10.1093/hmg/ddt587
PMCID: PMC3959809  PMID: 24256812
18.  No evidence for shared genetic basis of common variants in multiple sclerosis and amyotrophic lateral sclerosis 
Human Molecular Genetics  2013;23(7):1916-1922.
Genome-wide association studies have been successful in identifying common variants that influence the susceptibility to complex diseases. From these studies, it has emerged that there is substantial overlap in susceptibility loci between diseases. In line with those findings, we hypothesized that shared genetic pathways may exist between multiple sclerosis (MS) and amyotrophic lateral sclerosis (ALS). While both diseases may have inflammatory and neurodegenerative features, epidemiological studies have indicated an increased co-occurrence within individuals and families. To this purpose, we combined genome-wide data from 4088 MS patients, 3762 ALS patients and 12 030 healthy control individuals in whom 5 440 446 single-nucleotide polymorphisms (SNPs) were successfully genotyped or imputed. We tested these SNPs for the excess association shared between MS and ALS and also explored whether polygenic models of SNPs below genome-wide significance could explain some of the observed trait variance between diseases. Genome-wide association meta-analysis of SNPs as well as polygenic analyses fails to provide evidence in favor of an overlap in genetic susceptibility between MS and ALS. Hence, our findings do not support a shared genetic background of common risk variants in MS and ALS.
doi:10.1093/hmg/ddt574
PMCID: PMC3943520  PMID: 24234648
19.  Homozygosity analysis in amyotrophic lateral sclerosis 
European Journal of Human Genetics  2013;21(12):1429-1435.
Amyotrophic lateral sclerosis (ALS) may appear to be familial or sporadic, with recognised dominant and recessive inheritance in a proportion of cases. Sporadic ALS may be caused by rare homozygous recessive mutations. We studied patients and controls from the UK and a multinational pooled analysis of GWAS data on homozygosity in ALS to determine any potential recessive variant leading to the disease. Six-hundred and twenty ALS and 5169 controls were studied in the UK cohort. A total of 7646 homozygosity segments with length >2 Mb were identified, and 3568 rare segments remained after filtering ‘common' segments. The mean total of the autosomal genome with homozygosity segments was longer in ALS than in controls (unfiltered segments, P=0.05). Two-thousand and seventeen ALS and 6918 controls were studied in the pooled analysis. There were more regions of homozygosity segments per case (P=1 × 10−5), a greater proportion of cases harboured homozygosity (P=2 × 10−5), a longer average length of segment (P=1 × 10−5), a longer total genome coverage (P=1 × 10−5), and a higher rate of these segments overlapped with RefSeq gene regions (P=1 × 10−5), in ALS patients than controls. Positive associations were found in three regions. The most significant was in the chromosome 21 SOD1 region, and also chromosome 1 2.9–4.8 Mb, and chromosome 5 in the 65 Mb region. There are more than twenty potential genes in these regions. These findings point to further possible rare recessive genetic causes of ALS, which are not identified as common variants in GWAS.
doi:10.1038/ejhg.2013.59
PMCID: PMC3829775  PMID: 23612577
amyotrophic lateral sclerosis; homozygosity; recessive
20.  Mutations in the Matrin 3 gene cause familial amyotrophic lateral sclerosis 
Nature neuroscience  2014;17(5):664-666.
MATR3 is an RNA/DNA binding protein that interacts with TDP-43, a major disease protein linked to amyotrophic lateral sclerosis (ALS) and fronto-temporal dementia. Using exome sequencing, we identified mutations in MATR3 in ALS kindreds. We also observed MATR3 pathology in the spinal cords of ALS cases with and without MATR3 mutations. Our data provide additional evidence supporting the role of aberrant RNA processing in motor neuron degeneration.
doi:10.1038/nn.3688
PMCID: PMC4000579  PMID: 24686783
22.  Homozygosity analysis in amyotrophic lateral sclerosis 
European journal of human genetics : EJHG  2013;21(12):10.1038/ejhg.2013.59.
Amyotrophic lateral sclerosis (ALS) may appear to be familial or sporadic, with recognized dominant and recessive inheritance in a proportion of cases. Sporadic ALS may be caused by rare homozygous recessive mutations. We studied patients and controls from the UK and a multinational pooled analysis of GWAS data on homozygosity in ALS to determine any potential recessive variant leading to the disease. 620 ALS and 5169 controls were studied in the UK cohort. A total of 7646 homozygosity segments with length >2Mb were identified, and 3568 rare segments remained after filtering “common” segments. The mean total of the autosomal genome with homozygosity segments was longer in ALS than in controls (unfiltered segments, p=0.05). 2017 ALS and 6918 controls were studied in the pooled analysis. There were more regions of homozygosity segments per case (p=1×10−5), a greater proportion of cases harboured homozygosity (p=2×10−5), a longer average length of segment (p=1×10−5), a longer total genome coverage (p=1×10−5), and a higher rate of these segments overlapped with RefSeq gene regions (p=1×10−5), in ALS patients than controls. Positive associations were found in three regions. The most significant was in the chromosome 21 SOD1 region, and also chromosome 1 2.9Mb to 4.8Mb, and chromosome 5 in the 65Mb region. There are more than twenty potential genes in these regions. These findings point to further possible rare recessive genetic causes of ALS which are not identified as common variants in GWAS.
doi:10.1038/ejhg.2013.59
PMCID: PMC3829775  PMID: 23612577
amyotrophic lateral sclerosis; homozygosity; genetics; recessive
23.  The p.A382T TARDBP gene mutation in Sardinian patients affected by Parkinson’s disease and other degenerative parkinsonisms 
Neurogenetics  2013;14(2):161-166.
Background
Based on our previous finding of the p.A382T founder mutation in ALS patients with concomitant parkinsonism in the Sardinian population, we hypothesized that the same variant may underlie PD and/or other forms of degenerative parkinsonism on this Mediterranean island.
Design
We screened a cohort of 611 patients with PD (544 cases) and other forms of degenerative parkinsonism (67 cases), and 604 unrelated controls for the c.1144G>A (p.A382T) missense mutation of the TARDBP gene.
Results
The p.A382T mutation was identified in 9 patients with parkinsonism. Of these, 5 (0.9% of PD patients) presented a typical PD (2 with familiar forms), while 4 patients (6.0% of all other forms of parkinsonism) presented a peculiar clinical presentation quite different from classical atypical parkinsonism with an overlap of extrapyramidal-pyramidal-cognitive clinical signs. The mutation was found in 8 Sardinian controls (1.3%) consistent with a founder mutation in the island population.
Conclusions
Our findings suggest that the clinical presentation of the p.A382T TARDBP gene mutation may include forms of parkinsonism in which the extrapyramidal signs are the crucial core of the disease at onset. These forms can present PSP or CBD-like clinical signs, with bulbar and/or extrabulbar pyramidal signs and cognitive impairment. No evidence of association has been found between TARDBP gene mutation and typical PD.
doi:10.1007/s10048-013-0360-2
PMCID: PMC3661017  PMID: 23546887
TARDBP gene mutation; degenerative parkinsonism; TDP-43 Proteinopathies; Sardinia
24.  UNC13A influences survival in Italian ALS patients: a population-based study 
Neurobiology of aging  2012;34(1):357.e1-357.e5.
The common variant rs12608932, located within an intron of UNC13A gene on chromosome 19p13.3, has been suggested to influence susceptibility to ALS, as well as survival, in patients of north European descent. To examine this possibility further, we evaluated the association of rs12608932 with susceptibility and survival in a population-based cohort of 500 Italian ALS patients and 1,457 Italian control samples. Although rs12608932 was not associated to ALS susceptibility in our series (p=0.124), it was significantly associated with survival under the recessive model (median survival for AA/AC genotypes = 3.5 years [IQR 2.2–6.4]; CC = 2.5 years [IQR 1.6–4.2]; p=0.017). Furthermore, rs12608932 genotype remained an independent prognostic factor in Cox multivariable analysis adjusting for other factors known to influence survival (p=0.023). Overall, minor allele carrier status of rs12608932 was strongly associated with an ~1-year reduction of survival in ALS patients, making it a significant determinant of phenotype variation. The identification of UNC13A as a modifier of prognosis among sporadic ALS patients potentially provides a new therapeutic target aimed at slowing disease progression.
doi:10.1016/j.neurobiolaging.2012.07.016
PMCID: PMC3483408  PMID: 22921269
25.  Extramotor Damage Is Associated with Cognition in Primary Lateral Sclerosis Patients 
PLoS ONE  2013;8(12):e82017.
Objectives
This is a cross-sectional study aimed at investigating cognitive performances in patients with primary lateral sclerosis (PLS) and using diffusion tensor (DT) magnetic resonance imaging (MRI) to determine the topographical distribution of microstructural white matter (WM) damage in patients with or without cognitive deficits.
Methods
DT MRI scans were obtained from 21 PLS patients and 35 age- and sex-matched healthy controls. All PLS patients underwent a comprehensive neuropsychological battery. Tract-based-spatial-statistics (TBSS) was used to perform a whole-brain voxel-wise analysis of fractional anisotropy (FA), axial, radial (radD) and mean diffusivity (MD).
Results
Ten PLS patients had abnormal scores in at least one neuropsychological test (PLS with cognitive deficits, PLS-cd). Compared with healthy controls and cognitively unimpaired PLS patients (PLS-cu), PLS-cd cases showed decreased FA and increased MD and radD in the corticospinal tract (CST), corpus callosum, brainstem, anterior limb of internal capsule, superior and inferior longitudinal fasciculi, fornix, thalamic radiations, and parietal lobes, bilaterally. Compared with healthy controls, PLS-cd patients showed further decreased FA and increased radD in the cerebellar WM, bilaterally. Compared with controls, PLS-cu patients showed decreased FA in the mid-body of corpus callosum. In PLS, executive and language test scores correlated with WM damage.
Conclusions
This is the first study evaluating the relationship between cognitive performance and WM tract damage in PLS patients. PLS can be associated with a multi-domain cognitive impairment. WM damage to interhemispheric, limbic and major associative WM tracts seem to be the structural correlate of cognitive abnormalities in these patients.
doi:10.1371/journal.pone.0082017
PMCID: PMC3857796  PMID: 24349172

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