Amyotrophic Lateral Sclerosis With Frontotemporal Dementia Research Articles

Clinical Determinants of Disease Progression in Amyotrophic Lateral Sclerosis-A Retrospective Cohort Study.

Background: Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that is ultimately fatal but characterized by substantial phenotypic heterogeneity, which is known to impact long-term course and survival. This study investigated clinical determinants of disease progression and outcome in a large cohort of patients with ALS. Methods: Retrospective analysis included comprehensive data from 625 patients who attended a tertiary ALS centre at least twice. Patients were stratified according to five distinct clinical phenotypes: classical ALS; bulbar ALS; ALS with frontotemporal dementia (ALS-FTD); upper motor neuron predominant (UMNP); and lower motor neuron predominant (LMNP). Results: This study confirmed higher age at symptom onset, shorter latency to diagnosis and more rapid decline in the revised ALS Functional Rating Scale sum score as predictors of poor prognosis. Hazard ratios for shorter survival were higher in patients with ALS-FTD versus classical ALS, and in patients with versus without chronic obstructive pulmonary disease (COPD). Mean survival was longest in the UMNP phenotype group. Conclusions: This study confirmed established predictors of shorter survival in ALS and showed that concomitant COPD in particular relates to poor outcome.

Overexpression of UBQLN1 reduces neuropathology in the P497S UBQLN2 mouse model of ALS/FTD

Missense mutations in UBQLN2 cause X-linked dominant inheritance of amyotrophic lateral sclerosis with frontotemporal dementia (ALS/FTD). UBQLN2 belongs to a family of four highly homologous proteins expressed in humans that play diverse roles in maintaining proteostasis, but whether one isoform can substitute for another is not known. Here, we tested whether overexpression of UBQLN1 can alleviate disease in the P497S UBQLN2 mouse model of ALS/FTD by crossing transgenic (Tg) mouse lines expressing the two proteins and characterizing the resulting genotypes using a battery of pathologic and behavioral tests. The pathologic findings revealed UBQLN1 overexpression dramatically reduced the burden of UBQLN2 inclusions, neuronal loss and disturbances in proteostasis in double Tg mice compared to single P497S Tg mice. The beneficial effects of UBQLN1 overexpression were primarily confirmed by behavioral improvements seen in rotarod performance and grip strength in male, but not female mice. Paradoxically, although UBQLN1 overexpression reduced pathologic signatures of disease in P497S Tg mice, female mice had larger percentage of body weight loss than males, and this correlated with a corresponding lack of behavioral improvements in the females. These findings lead us to speculate that methods to upregulate UBQLN1 expression may reduce pathogenicity caused by UBQLN2 mutations, but may also lead to gender-specific outcomes that will have to be carefully weighed with the therapeutic benefits of UBQLN1 upregulation.

Quality-control mechanisms targeting translationally stalled and C-terminally extended poly(GR) associated with ALS/FTD

Maintaining the fidelity of nascent peptide chain (NP) synthesis is essential for proteome integrity and cellular health. Ribosome-associated quality control (RQC) serves to resolve stalled translation, during which untemplated Ala/Thr residues are added C terminally to stalled peptide, as shown during C-terminal Ala and Thr addition (CAT-tailing) in yeast. The mechanism and biological effects of CAT-tailing-like activity in metazoans remain unclear. Here we show that CAT-tailing-like modification of poly(GR), a dipeptide repeat derived from amyotrophic lateral sclerosis with frontotemporal dementia (ALS/FTD)-associated GGGGCC (G4C2) repeat expansion in C9ORF72, contributes to disease. We find that poly(GR) can act as a mitochondria-targeting signal, causing some poly(GR) to be cotranslationally imported into mitochondria. However, poly(GR) translation on mitochondrial surface is frequently stalled, triggering RQC and CAT-tailing-like C-terminal extension (CTE). CTE promotes poly(GR) stabilization, aggregation, and toxicity. Our genetic studies in Drosophila uncovered an important role of the mitochondrial protease YME1L in clearing poly(GR), revealing mitochondria as major sites of poly(GR) metabolism. Moreover, the mitochondria-associated noncanonical Notch signaling pathway impinges on the RQC machinery to restrain poly(GR) accumulation, at least in part through the AKT/VCP axis. The conserved actions of YME1L and noncanonical Notch signaling in animal models and patient cells support their fundamental involvement in ALS/FTD.

2-Deoxy-2-[18 F]fluoro-d-glucose positron emission tomography, cortical thickness and white matter graph network abnormalities in brains of patients with amyotrophic lateral sclerosis and frontotemporal dementia suggest early neuronopathy rather than axonopathy.

Amyotrophic lateral sclerosis (ALS) is a motor neuron disorder, although extra-motor degeneration is well recognized, especially in frontotemporal regions manifested as ALS with frontotemporal dementia (ALS-FTD). Previous neuroimaging studies of the brains of ALS-FTD patients have measured abnormalities of either grey matter (GM) or white matter (WM) structures but not of both together. Therefore, the aim was to evaluate both GM and WM in the same ALS-FTD patient using functional and structural neuroimaging. By doing so, insights could be gained into whether neurodegeneration in ALS-FTD is primarily a neuronopathy or axonopathy. After high-resolution brain 2-deoxy-2-[18 F]fluoro-D-glucose (18 F-FDG) positron emission tomography (PET) and magnetic resonance imaging (MRI) scans were obtained in ALS-FTD patients and in age- and sex-matched neurological controls, changes in metabolic rate, cortical thickness (CT) and WM network analysis using graph theory were analyzed. Significant reductions in 18 F-FDG PET metabolism, CT and WM connections were observed in motor and extra-motor brain regions of ALS-FTD patients compared to controls. Both CT and underlying WM networks were abnormal in frontal, temporal, parietal and occipital lobes of ALS-FTD patients with 86 of 90 brain regions showing reductions of CT. Abnormalities in significantly fewer WM networks underlying the affected cortical regions suggest that neurodegeneration in brains of ALS-FTD patients is primarily a 'neuronopathy' rather than an 'axonopathy.'

Validation of the revised classification of cognitive and behavioural impairment in ALS

ObjectiveIn 2017, the diagnostic criteria for cognitive and behavioural impairment in amyotrophic lateral sclerosis (ALS) with frontotemporal dementia (ALSFTD-1) have been modified (ALSFTD-2) with the inclusion of a novel category...

The applause sign in frontotemporal lobar degeneration and related conditions

The applause sign, i.e., the inability to execute the same amount of claps as performed by the examiner, was originally reported as a sign specific for progressive supranuclear palsy (PSP). Recent research, however, has provided evidence for the occurrence of the applause sign in various conditions. The aim of this study was to determine the prevalence of the applause sign and correlate its presence with neuropsychological and MRI volumetry findings in frontotemporal lobar degeneration and related conditions. The applause sign was elicited with the three clap test (TCT), with a higher score indicating poorer performance. Data were recorded from 272 patients from the cohort of the German consortium for frontotemporal lobar degeneration (FTLDc): 111 with behavioral variant frontotemporal dementia (bvFTD), 98 with primary progressive aphasia (PPA), 30 with progressive supranuclear palsy Richardson's syndrome, 17 with corticobasal syndrome (CBS) and 16 with amyotrophic lateral sclerosis with frontotemporal dementia (ALS/FTD). For comparison, 29 healthy elderly control subjects (HC) were enrolled in the study. All subjects underwent detailed language and neuropsychological assessment. In a subset of 156 subjects, atlas-based volumetry was performed. The applause sign occurred in all patient groups (40% in PSP, 29.5% in CBS, 25% in ALS/FTD, 13.3% in PPA and 9.0% in bvFTD) but not in healthy controls. The prevalence was highest in PSP patients. It was significantly more common in PSP as compared to bvFTD, PPA and HC. The comparison between the other groups failed to show a significant difference regarding the occurrence of the applause sign. The applause sign was highly correlated to a number of neuropsychological findings, especially to measures of executive, visuospatial, and language function as well as measures of disease severity. TCT scores showed an inverse correlation with the volume of the ventral diencephalon and the pallidum. Furthermore the volume of the ventral diencephalon and pallidum were significantly smaller in patients displaying the applause sign. Our study confirms the occurrence of the applause sign in bvFTD, PSP and CBS and adds PPA and ALS/FTD to these conditions. Although still suggestive of PSP, clinically it must be interpreted with caution. From the correlation with various cognitive measures we suggest the applause sign to be indicative of disease severity. Furthermore we suggest that the applause sign represents dysfunction of the pallidum and the subthalamic nucleus, structures which are known to play important roles in response inhibition.

Depletion of Ubiquilin induces an augmentation in soluble ubiquitinated Drosophila TDP-43 to drive neurotoxicity in the fly

The proteostasis machinery has critical functions in metabolically active cells such as neurons. Ubiquilins (UBQLNs) may decide the fate of proteins, with its ability to bind and deliver ubiquitinated misfolded or no longer functionally required proteins to the ubiquitin-proteasome system (UPS) and/or autophagy. Missense mutations in UBQLN2 have been linked to X-linked dominant amyotrophic lateral sclerosis with frontotemporal dementia (ALS-FTD). Although aggregation-prone TAR DNA-binding protein 43 (TDP-43) has been recognized as a major component of the ubiquitin pathology, the mechanisms by which UBQLN involves in TDP-43 proteinopathy have not yet been elucidated in detail. We previously characterized a new Drosophila Ubiquilin (dUbqn) knockdown model that produces learning/memory and locomotive deficits during the proteostasis impairment. In the present study, we demonstrated that the depletion of dUbqn markedly affected the expression and sub-cellular localization of Drosophila TDP-43 (TBPH), resulting in a cytoplasmic ubiquitin-positive (Ub+) TBPH pathology. Although we found that the knockdown of dUbqn widely altered and affected the turnover of a large number of proteins, we herein showed that an augmented soluble cytoplasmic Ub+-TBPH is as a crucial source of neurotoxicity following the depletion of dUbqn. We demonstrated that dUbqn knockdown-related neurotoxicity may be rescued by either restoring the proteostasis machinery or reducing the expression of TBPH. These novel results extend our knowledge on the UBQLN loss-of-function pathomechanism and may contribute to the identification of new therapeutics for ALS-FTD and aging-related diseases.

Brain Parenchymal Fraction: A Relatively Simple MRI Measure to Clinically Distinguish ALS Phenotypes.

Even though neuroimaging and clinical studies indicate that amyotrophic lateral sclerosis (ALS) manifests with distinct clinical phenotypes, no objective test exists to assess upper motor degeneration in ALS. There is great interest in identifying biomarkers of ALS to allow earlier diagnosis and to recognize disease subtypes. Current quantitative neuroimaging techniques such as T2 relaxometry and diffusion tensor imaging are time-consuming to use in clinical settings due to extensive postprocessing requirements. Therefore, we aimed to study the potential role of brain parenchymal fraction (BPF) as a relatively simple quantitative measure for distinguishing ALS phenotypes. T1-weighted MR images of brain were obtained in 15 neurological controls and 88 ALS patients categorized into 4 distinct clinical phenotypes, upper motor neuron- (UMN-) predominant ALS patients with/without corticospinal tract (CST) hyperintensity on T2/PD-weighted images, classic ALS, and ALS with frontotemporal dementia (ALS-FTD). BPF was calculated using intracranial grey matter, white matter, and cerebrospinal fluid volumes obtained in control and ALS subgroups using SPM8 software. Only ALS-FTD patients had significant reduction in BPF when compared to controls and nondemented ALS patients. Correlation of clinical measures such as disease duration with BPF further supports the view that the BPF could be a potential biomarker for clinical diagnosis of ALS-FTD patients.

UBQLN2/P62 cellular recycling pathways in amyotrophic lateral sclerosis and frontotemporal dementia

Recent findings highlight a pathologic and functional convergence in amyotrophic lateral sclerosis (ALS) and amyotrophic lateral sclerosis with frontotemporal dementia (ALS-FTD) at the level of protein recycling and disposal. Genes linked to rare cases of familial ALS and ALS-FTD, like UBQLN2, OPTN, SQSTM1/p62, and VCP, may converge onto a unifying pathogenic pathway and thereby provide novel therapeutic targets common to a spectrum of etiologically diverse forms of ALS and ALS-FTD. Interactions between these genes need to be further explored to understand their common molecular pathways. Future efforts should be directed toward generation and characterization of in vivo models to dissect the pathogenic mechanisms of ALS and ALS-FTD and the role of protein degradation pathways, both centrally, at the cell body, and peripherally, at the level of the synapse. Such efforts will rapidly accelerate the discovery of new drugs that regulate accumulation of pathogenic proteins and their downstream consequences in ALS and ALS-FTD and, possibly, other neurodegenerative diseases as well.

Distinctions between the dementia in Amyotrophic Lateral Sclerosis with Frontotemporal Dementia and the dementia of Alzheimer's disease

The clinical entity of Amyotrophic Lateral Sclerosis with Frontotemporal Dementia (ALS-FTD) has only recently been recognized as an important neurodegenerative disease. As in isolated FTD, the behavioral and personality changes in ALS-FTD might be more characteristic than its cognitive changes. We aimed to characterize the behavioral and cognitive deficits in ALS-FTD, and contrast this profile with that of the most common form of dementia, AD, to assist ALS clinicians in recognizing the syndrome early in its course. Specifically, we hypothesized that a modified version of the Frontal Behavioral Inventory (FBI-mod), a brief questionnaire self-administered by a caregiver, along with just a few cognitive tests, would be clinically useful in distinguishing the dementia in ALS-FTD from the dementia of AD. We administered a battery of neuropsychological tests to 15 patients who met established criteria for Amyotrophic Lateral Sclerosis with Frontotemporal Dementia and to 30 patients who met established criteria for probable Alzheimer's disease. The FBI-mod was completed by caregivers. We found that the FBI-mod, age-corrected Z scores for the Mini-Mental State Examination (MMSE), a test of delayed recall, and a word fluency measure together discriminated between ALS-FTD and AD. ALS-FTD was characterized by more abnormal FBI scores and poor word fluency, in the presence of relatively normal overall cognitive status (MMSE) and/or delayed recall.