TDP-43 pathology disrupts nuclear pore complexes and nucleocytoplasmic transport in ALS/FTD.

The cytoplasmic mislocalization and aggregation of TAR DNA-binding protein-43 (TDP-43) is a common histopathological hallmark of the amyotrophic lateral sclerosis and frontotemporal dementia disease spectrum (ALS/FTD). However, the composition of aggregates and their contribution to the disease process remain unknown. Here we used proximity-dependent biotin identification (BioID) to interrogate the interactome of detergent-insoluble TDP-43 aggregates and found them enriched for components of the nuclear pore complex and nucleocytoplasmic transport machinery.

Clinical and neuropathological features of ALS/FTD with TIA1 mutations.

Mutations in the stress granule protein T-cell restricted intracellular antigen 1 (TIA1) were recently shown to cause amyotrophic lateral sclerosis (ALS) with or without frontotemporal dementia (FTD). Here, we provide detailed clinical and neuropathological descriptions of nine cases with TIA1 mutations, together with comparisons to sporadic ALS (sALS) and ALS due to repeat expansions in C9orf72 (C9orf72+). All nine patients with confirmed mutations in TIA1 were female.

TIA1 Mutations in Amyotrophic Lateral Sclerosis and Frontotemporal Dementia Promote Phase Separation and Alter Stress Granule Dynamics.

Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are age-related neurodegenerative disorders with shared genetic etiologies and overlapping clinical and pathological features. Here we studied a novel ALS/FTD family and identified the P362L mutation in the low-complexity domain (LCD) of T cell-restricted intracellular antigen-1 (TIA1). Subsequent genetic association analyses showed an increased burden of TIA1 LCD mutations in ALS patients compared to controls (p = 8.

Conserved DNA methylation combined with differential frontal cortex and cerebellar expression distinguishes C9orf72-associated and sporadic ALS, and implicates SERPINA1 in disease.

We previously found C9orf72-associated (c9ALS) and sporadic amyotrophic lateral sclerosis (sALS) brain transcriptomes comprise thousands of defects, among which, some are likely key contributors to ALS pathogenesis. We have now generated complementary methylome data and combine these two data sets to perform a comprehensive "multi-omic" analysis to clarify the molecular mechanisms initiating RNA misregulation in ALS. We found that c9ALS and sALS patients have generally distinct but overlapping methylome profiles, and that the c9ALS- and sALS-affected genes and pathways have similar biological functions, indicating conserved pathobiology in disease.

Repetitive element transcripts are elevated in the brain of C9orf72 ALS/FTLD patients.

Significant transcriptome alterations are detected in the brain of patients with amyotrophic lateral sclerosis (ALS), including carriers of the C9orf72 repeat expansion and C9orf72-negative sporadic cases. Recently, the expression of repetitive element transcripts has been associated with toxicity and, while increased repetitive element expression has been observed in several neurodegenerative diseases, little is known about their contribution to ALS. To assess whether aberrant expression of repetitive element sequences are observed in ALS, we analysed RNA sequencing data from C9orf72-positive and sporadic ALS cases, as well as healthy controls.

Phosphorylated neurofilament heavy chain: A biomarker of survival for C9ORF72-associated amyotrophic lateral sclerosis.

As potential treatments for C9ORF72-associated amyotrophic lateral sclerosis (c9ALS) approach clinical trials, the identification of prognostic biomarkers for c9ALS becomes a priority. We show that levels of phosphorylated neurofilament heavy chain (pNFH) in cerebrospinal fluid (CSF) predict disease status and survival in c9ALS patients, and are largely stable over time. Moreover, c9ALS patients exhibit higher pNFH levels, more rapid disease progression, and shorter survival after disease onset than ALS patients without C9ORF72 expansions.

In-depth clinico-pathological examination of RNA foci in a large cohort of C9ORF72 expansion carriers.

A growing body of evidence suggests that a loss of chromosome 9 open reading frame 72 (C9ORF72) expression, formation of dipeptide-repeat proteins, and generation of RNA foci contribute to disease pathogenesis in amyotrophic lateral sclerosis and frontotemporal dementia. Although the levels of C9ORF72 transcripts and dipeptide-repeat proteins have already been examined thoroughly, much remains unknown about the role of RNA foci in C9ORF72-linked diseases. As such, we performed a comprehensive RNA foci study in an extensive pathological cohort of C9ORF72 expansion carriers (n = 63).

Poly(GP) proteins are a useful pharmacodynamic marker for -associated amyotrophic lateral sclerosis.

There is no effective treatment for amyotrophic lateral sclerosis (ALS), a devastating motor neuron disease. However, discovery of a GC repeat expansion in the gene as the most common genetic cause of ALS has opened up new avenues for therapeutic intervention for this form of ALS. GC repeat expansion RNAs and proteins of repeating dipeptides synthesized from these transcripts are believed to play a key role in -associated ALS (c9ALS).

NEK1 variants confer susceptibility to amyotrophic lateral sclerosis.

To identify genetic factors contributing to amyotrophic lateral sclerosis (ALS), we conducted whole-exome analyses of 1,022 index familial ALS (FALS) cases and 7,315 controls. In a new screening strategy, we performed gene-burden analyses trained with established ALS genes and identified a significant association between loss-of-function (LOF) NEK1 variants and FALS risk. Independently, autozygosity mapping for an isolated community in the Netherlands identified a NEK1 p.

Defining SOD1 ALS natural history to guide therapeutic clinical trial design.

Importance: Understanding the natural history of familial amyotrophic lateral sclerosis (ALS) caused by SOD1 mutations (ALS) will provide key information for optimising clinical trials in this patient population.

Objective: To establish an updated natural history of ALS.

Design, Setting And Participants: Retrospective cohort study from 15 medical centres in North America evaluated records from 175 patients with ALS with genetically confirmed SOD1 mutations, cared for after the year 2000.

C9ORF72 poly(GA) aggregates sequester and impair HR23 and nucleocytoplasmic transport proteins.

Neuronal inclusions of poly(GA), a protein unconventionally translated from G4C2 repeat expansions in C9ORF72, are abundant in patients with frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS) caused by this mutation. To investigate poly(GA) toxicity, we generated mice that exhibit poly(GA) pathology, neurodegeneration and behavioral abnormalities reminiscent of FTD and ALS. These phenotypes occurred in the absence of TDP-43 pathology and required poly(GA) aggregation.

C9orf72 promoter hypermethylation is reduced while hydroxymethylation is acquired during reprogramming of ALS patient cells.

Among several genetic mutations known to cause amyotrophic lateral sclerosis (ALS), a hexanucleotide repeat expansion in the C9orf72 gene is the most common. In approximately 30% of C9orf72-ALS cases, 5-methylcytosine (5mC) levels within the C9orf72 promoter are increased, resulting in a modestly attenuated phenotype. The developmental timing of C9orf72 promoter hypermethylation and the reason why it occurs in only a subset of patients remain unknown.

Chronic traumatic encephalopathy pathology in a neurodegenerative disorders brain bank.

Chronic traumatic encephalopathy (CTE) is a progressive neurodegenerative disorder linked to repetitive traumatic brain injury (TBI) and characterized by deposition of hyperphosphorylated tau at the depths of sulci. We sought to determine the presence of CTE pathology in a brain bank for neurodegenerative disorders for individuals with and without a history of contact sports participation. Available medical records of 1721 men were reviewed for evidence of past history of injury or participation in contact sports.

Novel clinical associations with specific C9ORF72 transcripts in patients with repeat expansions in C9ORF72.

The loss of chromosome 9 open reading frame 72 (C9ORF72) expression, associated with C9ORF72 repeat expansions, has not been examined systematically. Three C9ORF72 transcript variants have been described thus far; the GGGGCC repeat is located between two non-coding exons (exon 1a and exon 1b) in the promoter region of transcript variant 2 (NM_018325.4) or in the first intron of variant 1 (NM_145005.

Cerebellar c9RAN proteins associate with clinical and neuropathological characteristics of C9ORF72 repeat expansion carriers.

Clinical and neuropathological characteristics associated with G4C2 repeat expansions in chromosome 9 open reading frame 72 (C9ORF72), the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia, are highly variable. To gain insight on the molecular basis for the heterogeneity among C9ORF72 mutation carriers, we evaluated associations between features of disease and levels of two abundantly expressed "c9RAN proteins" produced by repeat-associated non-ATG (RAN) translation of the expanded repeat. For these studies, we took a departure from traditional immunohistochemical approaches and instead employed immunoassays to quantitatively measure poly(GP) and poly(GA) levels in cerebellum, frontal cortex, motor cortex, and/or hippocampus from 55 C9ORF72 mutation carriers [12 patients with ALS, 24 with frontotemporal lobar degeneration (FTLD) and 19 with FTLD with motor neuron disease (FTLD-MND)].

Distinct brain transcriptome profiles in C9orf72-associated and sporadic ALS.

Increasing evidence suggests that defective RNA processing contributes to the development of amyotrophic lateral sclerosis (ALS). This may be especially true for ALS caused by a repeat expansion in C9orf72 (c9ALS), in which the accumulation of RNA foci and dipeptide-repeat proteins are expected to modify RNA metabolism. We report extensive alternative splicing (AS) and alternative polyadenylation (APA) defects in the cerebellum of c9ALS subjects (8,224 AS and 1,437 APA), including changes in ALS-associated genes (for example, ATXN2 and FUS), and in subjects with sporadic ALS (sALS; 2,229 AS and 716 APA).

Jump from pre-mutation to pathologic expansion in C9orf72.

An expanded G4C2 repeat in C9orf72 represents the most common known genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD). However, the lower limit for pathological expansions is unknown (the suggested cutoff is 30 repeats). It has been proposed that the expansion might have occurred only once in human history and subsequently spread throughout the population.

Neurodegeneration. C9ORF72 repeat expansions in mice cause TDP-43 pathology, neuronal loss, and behavioral deficits.

The major genetic cause of frontotemporal dementia and amyotrophic lateral sclerosis is a G4C2 repeat expansion in C9ORF72. Efforts to combat neurodegeneration associated with "c9FTD/ALS" are hindered by a lack of animal models recapitulating disease features. We developed a mouse model to mimic both neuropathological and clinical c9FTD/ALS phenotypes.

Whole-genome sequencing reveals important role for TBK1 and OPTN mutations in frontotemporal lobar degeneration without motor neuron disease.

Frontotemporal lobar degeneration with TAR DNA-binding protein 43 inclusions (FTLD-TDP) is the most common pathology associated with frontotemporal dementia (FTD). Repeat expansions in chromosome 9 open reading frame 72 (C9ORF72) and mutations in progranulin (GRN) are the major known genetic causes of FTLD-TDP; however, the genetic etiology in the majority of FTLD-TDP remains unexplained. In this study, we performed whole-genome sequencing in 104 pathologically confirmed FTLD-TDP patients from the Mayo Clinic brain bank negative for C9ORF72 and GRN mutations and report on the contribution of rare single nucleotide and copy number variants in 21 known neurodegenerative disease genes.

A truncating SOD1 mutation, p.Gly141X, is associated with clinical and pathologic heterogeneity, including frontotemporal lobar degeneration.

Amyotrophic lateral sclerosis (ALS) is a degenerative disorder affecting upper and lower motor neurons, but it is increasingly recognized to affect other systems, with cognitive impairment resembling frontotemporal dementia (FTD) in some patients. We report clinical and pathologic findings of a family with ALS due to a truncating mutation, p.Gly141X, in copper/zinc superoxide dismutase (SOD1).

Genetic modifiers in carriers of repeat expansions in the C9ORF72 gene.

Background: Hexanucleotide repeat expansions in chromosome 9 open reading frame 72 (C9ORF72) are causative for frontotemporal dementia (FTD) and motor neuron disease (MND). Substantial phenotypic heterogeneity has been described in patients with these expansions. We set out to identify genetic modifiers of disease risk, age at onset, and survival after onset that may contribute to this clinical variability.