Trial of Antisense Oligonucleotide Tofersen for SOD1 ALS.

BACKGROUND: The intrathecally administered antisense oligonucleotide tofersen reduces synthesis of the superoxide dismutase 1 (SOD1) protein and is being studied in patients with amyotrophic lateral sclerosis (ALS) associated with mutations in SOD1 (SOD1 ALS). METHODS: In this phase 3 trial, we randomly assigned adults with SOD1 ALS in a 2:1 ratio to receive eight doses of tofersen (100 mg) or placebo over a period of 24 weeks. The primary end point was the change from baseline to week 28 in the total score on the ALS Functional Rating Scale-Revised (ALSFRS-R; range, 0 to 48, with higher scores indicating better function) among participants predicted to have faster-progressing disease. Secondary end points included changes in the total concentration of SOD1 protein in cerebrospinal fluid (CSF), in the concentration of neurofilament light chains in plasma, in slow vital capacity, and in handheld dynamometry in 16 muscles. A combined analysis of the randomized component of the trial and its open-label extension at 52 weeks compared the results in participants who started tofersen at trial entry (early-start cohort) with those in participants who switched from placebo to the drug at week 28 (delayed-start cohort). RESULTS: A total of 72 participants received tofersen (39 predicted to have faster progression), and 36 received placebo (21 predicted to have faster progression). Tofersen led to greater reductions in concentrations of SOD1 in CSF and of neurofilament light chains in plasma than placebo. In the faster-progression subgroup (primary analysis), the change to week 28 in the ALSFRS-R score was -6.98 with tofersen and -8.14 with placebo (difference, 1.2 points; 95% confidence interval [CI], -3.2 to 5.5; P = 0.97). Results for secondary clinical end points did not differ significantly between the two groups. A total of 95 participants (88%) entered the open-label extension. At 52 weeks, the change in the ALSFRS-R score was -6.0 in the early-start cohort and -9.5 in the delayed-start cohort (difference, 3.5 points; 95% CI, 0.4 to 6.7); non-multiplicity-adjusted differences favoring early-start tofersen were seen for other end points. Lumbar puncture-related adverse events were common. Neurologic serious adverse events occurred in 7% of tofersen recipients. CONCLUSIONS: In persons with SOD1 ALS, tofersen reduced concentrations of SOD1 in CSF and of neurofilament light chains in plasma over 28 weeks but did not improve clinical end points and was associated with adverse events. The potential effects of earlier as compared with delayed initiation of tofersen are being further evaluated in the extension phase. (Funded by Biogen; VALOR and OLE ClinicalTrials.gov numbers, NCT02623699 and NCT03070119; EudraCT numbers, 2015-004098-33 and 2016-003225-41.).

The SYNGAP1 3'UTR Variant in ALS Patients Causes Aberrant SYNGAP1 Splicing and Dendritic Spine Loss by Recruiting HNRNPK.

Fused in sarcoma (FUS) is a pathogenic RNA-binding protein in amyotrophic lateral sclerosis (ALS). We previously reported that FUS stabilizes Synaptic Ras-GTPase activating protein 1 (Syngap1) mRNA at its 3' untranslated region (UTR) and maintains spine maturation. To elucidate the pathologic roles of this mechanism in ALS patients, we identified the SYNGAP1 3'UTR variant rs149438267 in seven (four males and three females) out of 807 ALS patients at the FUS binding site from a multicenter cohort in Japan. Human-induced pluripotent stem cell (hiPSC)-derived motor neurons with the SYNGAP1 variant showed aberrant splicing, increased isoform α1 levels, and decreased isoform γ levels, which caused dendritic spine loss. Moreover, the SYNGAP1 variant excessively recruited FUS and heterogeneous nuclear ribonucleoprotein K (HNRNPK), and antisense oligonucleotides (ASOs) blocking HNRNPK altered aberrant splicing and ameliorated dendritic spine loss. These data suggest that excessive recruitment of RNA-binding proteins, especially HNRNPK, as well as changes in SYNGAP1 isoforms, are crucial for spine formation in motor neurons.SIGNIFICANCE STATEMENT It is not yet known which RNAs cause the pathogenesis of amyotrophic lateral sclerosis (ALS). We previously reported that Fused in sarcoma (FUS), a pathogenic RNA-binding protein in ALS, stabilizes synaptic Ras-GTPase activating protein 1 (Syngap1) mRNA at its 3' untranslated region (UTR) and maintains dendritic spine maturation. To elucidate whether this mechanism is crucial for ALS, we identified the SYNGAP1 3'UTR variant rs149438267 at the FUS binding site. Human-induced pluripotent stem cell (hiPSC)-derived motor neurons with the SYNGAP1 variant showed aberrant splicing, which caused dendritic spine loss along with excessive recruitment of FUS and heterogeneous nuclear ribonucleoprotein K (HNRNPK). Our findings that dendritic spine loss is because of excess recruitment of RNA-binding proteins provide a basis for the future exploration of ALS-related RNA-binding proteins.

Amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis is a fatal CNS neurodegenerative disease. Despite intensive research, current management of amyotrophic lateral sclerosis remains suboptimal from diagnosis to prognosis. Recognition of the phenotypic heterogeneity of amyotrophic lateral sclerosis, global CNS dysfunction, genetic architecture, and development of novel diagnostic criteria is clarifying the spectrum of clinical presentation and facilitating diagnosis. Insights into the pathophysiology of amyotrophic lateral sclerosis, identification of disease biomarkers and modifiable risks, along with new predictive models, scales, and scoring systems, and a clinical trial pipeline of mechanism-based therapies, are changing the prognostic landscape. Although most recent advances have yet to translate into patient benefit, the idea of amyotrophic lateral sclerosis as a complex syndrome is already having tangible effects in the clinic. This Seminar will outline these insights and discuss the status of the management of amyotrophic lateral sclerosis for the general neurologist, along with future prospects that could improve care and outcomes for patients with amyotrophic lateral sclerosis.

Genetic factors affecting survival in Japanese patients with sporadic amyotrophic lateral sclerosis: a genome-wide association study and verification in iPSC-derived motor neurons from patients.

BACKGROUND: Several genetic factors are associated with the pathogenesis of sporadic amyotrophic lateral sclerosis (ALS) and its phenotypes, such as disease progression. Here, in this study, we aimed to identify the genes that affect the survival of patients with sporadic ALS. METHODS: We enrolled 1076 Japanese patients with sporadic ALS with imputed genotype data of 7 908 526 variants. We used Cox proportional hazards regression analysis with an additive model adjusted for sex, age at onset and the first two principal components calculated from genotyped data to conduct a genome-wide association study. We further analysed messenger RNA (mRNA) and phenotype expression in motor neurons derived from induced pluripotent stem cells (iPSC-MNs) of patients with ALS. RESULTS: Three novel loci were significantly associated with the survival of patients with sporadic ALS-FGF1 at 5q31.3 (rs11738209, HR=2.36 (95% CI, 1.77 to 3.15), p=4.85×10-9), THSD7A at 7p21.3 (rs2354952, 1.38 (95% CI, 1.24 to 1.55), p=1.61×10-8) and LRP1 at 12q13.3 (rs60565245, 2.18 (95% CI, 1.66 to 2.86), p=2.35×10-8). FGF1 and THSD7A variants were associated with decreased mRNA expression of each gene in iPSC-MNs and reduced in vitro survival of iPSC-MNs obtained from patients with ALS. The iPSC-MN in vitro survival was reduced when the expression of FGF1 and THSD7A was partially disrupted. The rs60565245 was not associated with LRP1 mRNA expression. CONCLUSIONS: We identified three loci associated with the survival of patients with sporadic ALS, decreased mRNA expression of FGF1 and THSD7A and the viability of iPSC-MNs from patients. The iPSC-MN model reflects the association between patient prognosis and genotype and can contribute to target screening and validation for therapeutic intervention.

Oral edaravone demonstrated a favorable safety profile in patients with amyotrophic lateral sclerosis after 48 weeks of treatment.

INTRODUCTION/AIMS: An intravenous (IV) formulation of edaravone has been shown to slow the rate of physical functional decline in amyotrophic lateral sclerosis (ALS). An oral suspension formulation of edaravone was recently approved by the United States Food and Drug Administration for use in patients with ALS. This study assessed the safety and tolerability of oral edaravone. METHODS: This global, open-label, phase 3 study evaluated the long-term safety and tolerability of oral edaravone in adults with ALS who had a baseline forced vital capacity ≥70% of predicted and disease duration ≤3 y. The primary safety analysis was assessed at weeks 24 and 48. Patients received a 105-mg dose of oral edaravone in treatment cycles replicating the dosing of IV edaravone. RESULTS: The study enrolled 185 patients (64.3% male; mean age, 59.9 y; mean disease duration, 1.56 y). The most common treatment-emergent adverse events (TEAEs) at week 48 were fall (22.2%), muscular weakness (21.1%) and constipation (17.8%). Serious TEAEs were reported by 25.9% of patients; the most common were worsening ALS symptoms, dysphagia, dyspnea, and respiratory failure. Twelve TEAEs leading to death were reported. Forty-six (24.9%) patients reported TEAEs that were considered related to study drug; the most common were fatigue, dizziness, headache, and constipation. Sixteen (8.6%) patients discontinued study drug due to TEAEs. No serious TEAEs were related to study drug. DISCUSSION: This study indicated that oral edaravone was well tolerated during 48 wk of treatment, with no new safety concerns identified.

Motor neuron TDP-43 proteinopathy in progressive supranuclear palsy and corticobasal degeneration.

TDP-43 is mislocalized from the nucleus and aggregates within the cytoplasm of affected neurons in cases of amyotrophic lateral sclerosis. TDP-43 pathology has also been found in brain tissues under non-amyotrophic lateral sclerosis conditions, suggesting mechanistic links between TDP-43-related amyotrophic lateral sclerosis and various neurological disorders. This study aimed to assess TDP-43 pathology in the spinal cord motor neurons of tauopathies. We examined 106 spinal cords from consecutively autopsied cases with progressive supranuclear palsy (n = 26), corticobasal degeneration (n = 12), globular glial tauopathy (n = 5), Alzheimer's disease (n = 21) or Pick's disease (n = 6) and neurologically healthy controls (n = 36). Ten of the progressive supranuclear palsy cases (38%) and seven of the corticobasal degeneration cases (58%) showed mislocalization and cytoplasmic aggregation of TDP-43 in spinal cord motor neurons, which was prominent in the cervical cord. TDP-43 aggregates were found to be skein-like, round-shaped, granular or dot-like and contained insoluble C-terminal fragments showing blotting pattern of amyotrophic lateral sclerosis or frontotemporal lobar degeneration. The lower motor neurons also showed cystatin-C aggregates, although Bunina bodies were absent in haematoxylin-eosin staining. The spinal cord TDP-43 pathology was often associated with TDP-43 pathology of the primary motor cortex. Positive correlations were shown between the severities of TDP-43 and four-repeat (4R)-tau aggregates in the cervical cord. TDP-43 and 4R-tau aggregates burdens positively correlated with microglial burden in anterior horn. TDP-43 pathology of spinal cord motor neuron did not develop in an age-dependent manner and was not found in the Alzheimer's disease, Pick's disease, globular glial tauopathy and control groups. Next, we assessed SFPQ expression in spinal cord motor neurons; SFPQ is a recently identified regulator of amyotrophic lateral sclerosis/frontotemporal lobar degeneration pathogenesis, and it is also reported that interaction between SFPQ and FUS regulates splicing of MAPT exon 10. Immunofluorescent and proximity-ligation assays revealed altered SFPQ/FUS-interactions in the neuronal nuclei of progressive supranuclear palsy, corticobasal degeneration and amyotrophic lateral sclerosis-TDP cases but not in Alzheimer's disease, Pick's disease and globular glial tauopathy cases. Moreover, SFPQ expression was depleted in neurons containing TDP-43 or 4R-tau aggregates of progressive supranuclear palsy and corticobasal degeneration cases. Our results indicate that progressive supranuclear palsy and corticobasal degeneration may have properties of systematic motor neuron TDP-43 proteinopathy, suggesting mechanistic links with amyotrophic lateral sclerosis-TDP. SFPQ dysfunction, arising from altered interaction with FUS, may be a candidate of the common pathway.

Safety and Clinical Benefits of Laryngeal Closure in Patients with Amyotrophic Lateral Sclerosis.

This study evaluated the safety of laryngeal closure and post-surgical changes in swallowing function of patients with amyotrophic lateral sclerosis (ALS) and proposed an appropriate surgical strategy for patients with ALS. Clinical and surgical data of 26 consecutive patients with ALS who underwent laryngeal closure at Nagoya University Hospital in Japan between 2003 and 2020 were retrospectively analyzed. Changes in swallowing functions were evaluated before and approximately 1 month post-surgery using Neuromuscular Disease Swallowing Status Scale (NdSSS), and Functional Oral Intake Scale (FOIS). The median operation time was 126 min (range, 51-163 min), and the median intraoperative blood loss was 20 mL (range, 0-88 mL). Among the 26 ALS patients who underwent laryngeal closure, grade 1 (mild) complications occurred in three patients (12%); however, no severe complications were observed. After surgery, 25 patients (96%) maintained the swallowing function and only one patient (4%) had deteriorating NdSSS and FOIS scores. No patients were referred to our hospital due to severe aspiration pneumonia after the surgery. Two patients did not require a feeding tube after the surgery and returned to oral intake. Laryngeal closure may be a safe surgical procedure for preventing chronic aspiration and may also maintain swallowing function of patients with ALS. Further multicenter prospective studies using the gold standard videofluoroscopic swallowing examination are required to support our findings.

Position-specific binding of FUS to nascent RNA regulates mRNA length.

More than half of all human genes produce prematurely terminated polyadenylated short mRNAs. However, the underlying mechanisms remain largely elusive. CLIP-seq (cross-linking immunoprecipitation [CLIP] combined with deep sequencing) of FUS (fused in sarcoma) in neuronal cells showed that FUS is frequently clustered around an alternative polyadenylation (APA) site of nascent RNA. ChIP-seq (chromatin immunoprecipitation [ChIP] combined with deep sequencing) of RNA polymerase II (RNAP II) demonstrated that FUS stalls RNAP II and prematurely terminates transcription. When an APA site is located upstream of an FUS cluster, FUS enhances polyadenylation by recruiting CPSF160 and up-regulates the alternative short transcript. In contrast, when an APA site is located downstream from an FUS cluster, polyadenylation is not activated, and the RNAP II-suppressing effect of FUS leads to down-regulation of the alternative short transcript. CAGE-seq (cap analysis of gene expression [CAGE] combined with deep sequencing) and PolyA-seq (a strand-specific and quantitative method for high-throughput sequencing of 3' ends of polyadenylated transcripts) revealed that position-specific regulation of mRNA lengths by FUS is operational in two-thirds of transcripts in neuronal cells, with enrichment in genes involved in synaptic activities.

Investigation of inpatient convalescent rehabilitation outcomes in branch atheromatous disease.

PURPOSE: We investigated inpatient convalescent rehabilitation outcomes of Branch atheromatous disease (BAD). SUBJECTS AND METHODS: The subjects were 116 patients with lenticulostriate artery territory - BAD (LSA-BAD) and 29 with paramedian pontine artery territory - BAD (PPA-BAD). For all patients, the National Institutes of Health Stroke Scale (NIHSS), Functional Independence Measure (FIM) scores, and Brunnstrom recovery stages (BRS) of the upper limb, fingers, and lower limb were measured on admission and at discharge. RESULTS: There were no significant differences in clinical characteristics on admission between the LSA-BAD and PPA-BAD groups. The neurological severity of PPA-BAD, as measured by the NIHSS, was significantly milder compared with that of LSA-BAD upon admission (p = 0.015) and at discharge (p = 0.001). Patients with LSA-BAD had significantly less improvement in the BRS of the upper limb (p = 0.001), fingers (p < 0.001), and lower limb (p = 0.007) at discharge. Furthermore, they had significantly smaller changes in BRS between admission and discharge for the upper limb (p = 0.033) and fingers (p = 0.014) compared with patients with PPA-BAD. The improvement in BRS for patients with LSA-BAD tended to be limited to two stages; however, both patients with LSA-BAD and PPA-BAD saw sufficient gains in FIM at discharge. CONCLUSION: Rehabilitation outcomes following BAD in the convalescent period should be assessed in terms of improvements in pure-motor hemiparesis and activities of daily living. Furthermore, the disturbance patterns in the corticospinal tract by ischemic stroke lesions may be different between LSA-BAD and PPA-BAD.

Intravenous immunoglobulin for chronic residual peripheral neuropathy in microscopic polyangiitis: A multicentre randomised double-blind trial.

OBJECTIVES: We conducted a Phase 3, multicentre, randomised, double-blind, placebo-controlled, parallel-group trial to evaluate the efficacy and safety of intravenous immunoglobulin (IVIg) in patients with glucocorticoid-refractory neuropathy associated with microscopic polyangiitis. METHODS: Patients received immunoglobulin or placebo intravenously for 5 consecutive days at baseline and after 4 weeks. The IVIg and placebo groups received IVIg and placebo, respectively, after 8 weeks. The primary and major secondary end-points were the least squares mean of the change in the manual muscle test (MMT) sum score after 8 and 4 weeks, respectively. RESULTS: A total of 37 patients were randomised into two groups (IVIg [19] and placebo [18]). The least squares mean for the change in the MMT sum score was 9.02 for IVIg and 6.71 for placebo (difference 2.32, 95% confidence interval -2.60 to 7.23, p = .345) after 8 weeks and 6.81 and 2.83 (difference 3.99, 95% confidence interval -1.22 to 9.19, p = .129), respectively, after 4 weeks. There were no new safety concerns for IVIg. CONCLUSIONS: MMT sum scores improved with IVIg compared with placebo after 8 weeks of dosing and two courses of treatment, but the differences were not statistically significant, and the results showed no clear efficacy of IVIg in this patient population. No new safety concerns were raised.

Functional connector hubs in the cerebellum.

Accumulating evidence from anatomical and neuroimaging studies suggests that the cerebellum is engaged in a variety of motor and cognitive tasks. Given its various functions, a key question is whether the cerebellum also plays an important role in the brain's integrative functions. Here, we hypothesize the existence of connector regions, also known as connector hubs, where multiple resting state networks converged in the cerebellum. To verify this, we employed a recently developed voxel-level network measure called functional connectivity overlap ratio (FCOR), which could be used to quantify the spatial extent of a region's connection to several large-scale cortical networks. Using resting state functional MRI data from 101 healthy participants, cerebellar FCOR maps were constructed and used to identify the locations of connector hubs in the cerebellum. Results showed that a number of cerebellar regions exhibited strong connectivity with multiple functional networks, verifying our hypothesis. These highly connected regions were located in the posterior cerebellum, especially in lobules VI, VII, and IX, and mainly connected to the core neurocognitive networks such as default mode and executive control networks. Regions associated with the sensorimotor network were also localized in lobule V, VI, and VIII, albeit in small clusters. These cerebellar connector hubs may play an essential role in the processing of information across the core neurocognitive networks.

Fiber-specific white matter analysis reflects upper motor neuron impairment in amyotrophic lateral sclerosis.

BACKGROUND AND PURPOSE: To clarify the relationship between fiber-specific white matter changes in amyotrophic lateral sclerosis (ALS) and clinical signs of upper motor neuron (UMN) involvement, we performed a fixel-based analysis (FBA), a novel framework for diffusion-weighted imaging analysis. METHODS: We enrolled 96 participants, including 48 nonfamilial ALS patients and 48 age- and sex-matched healthy controls (HCs), in this study and conducted whole-brain FBA and voxel-based morphometry analysis. We compared the fiber density (FD), fiber morphology (fiber cross-section [FC]), and a combined index of FD and FC (FDC) between the ALS and HC groups. We performed a tract-of-interest analysis to extract FD values across the significant regions in the whole-brain analysis. Then, we evaluated the associations between FD values and clinical variables. RESULTS: The bilateral corticospinal tracts (CSTs) and the corpus callosum (CC) showed reduced FD and FDC in ALS patients compared with HCs (p < 0.05, familywise error-corrected), and the comparison of FCs revealed no region that was significantly different from another. Voxel-based morphometry showed cortical volume reduction in the regions, including the primary motor area. Clinical scores showed correlations with FD values in the CSTs (UMN score: rho = -0.530, p < 0.001; central motor conduction time [CMCT] in the upper limb: rho = -0.474, p = 0.008; disease duration: rho = -0.383, p = 0.007; ALS Functional Rating Scale-Revised: rho = 0.340, p = 0.018). In addition, patients whose CMCT was not calculated due to unevoked waves also showed FD reduction in the CSTs. CONCLUSIONS: Our findings suggest that FD values in the CST estimated via FBA can be potentially used in evaluating UMN impairments.

Serum asymmetric dimethylarginine level correlates with the progression and prognosis of amyotrophic lateral sclerosis.

BACKGROUND AND PURPOSE: The aim was to investigate the association between serum asymmetric dimethylarginine (ADMA) levels and the progression and prognosis of amyotrophic lateral sclerosis (ALS), and to compare cerebrospinal fluid (CSF) and serum ADMA levels with other biomarkers of ALS. METHODS: Serum ADMA levels of sporadic ALS patients (n = 68), disease control patients (n = 54) and healthy controls (n = 20) were measured using liquid chromatography tandem mass spectrometry. Correlations of the ADMA level and other markers (nitric oxide and neurofilament light chain levels) were analyzed. Changes in the ALS Functional Rating Scale Revised (ALSFRS-R) score from the onset of disease (ALSFRS-R pre-slope) was used to assess disease progression. Survival was evaluated using the Cox proportional hazards model and Kaplan-Meier analysis. RESULTS: The serum ADMA level was substantially higher in patients with ALS than in healthy controls and disease controls. Serum ADMA level correlated with CSF ADMA level (r = 0.591, p < 0.0001) and was independently associated with the ALSFRS-R pre-slope (r = 0.505, p < 0.0001). Patients with higher serum ADMA levels had less favorable prognoses. CSF ADMA level significantly correlated with CSF neurofilament light chain level (r = 0.456, p = 0.0002) but not with nitric oxide level (r = 0.194, p = 0.219). CONCLUSION: Serum ADMA level is an independent biomarker of ALS disease progression and prognosis and reflects the degree of motor neuron degeneration.

Analysis of relapse by inflammatory Rasch-built overall disability scale status in the PATH study of subcutaneous immunoglobulin in chronic inflammatory demyelinating polyneuropathy.

Clinical trials in chronic inflammatory demyelinating polyneuropathy (CIDP) often assess efficacy using the ordinal Inflammatory Neuropathy Cause and Treatment (INCAT) disability score. Here, data from the PATH study was reanalyzed using change in Inflammatory Rasch-built Overall Disability Scale (I-RODS) to define CIDP relapse instead of INCAT. The PATH study comprised an intravenous immunoglobulin (IVIG) dependency period and an IVIG (IgPro10 [Privigen]) restabilization period; subjects were then randomized to weekly maintenance subcutaneous immunoglobulin (SCIG; IgPro20 [Hizentra]) 0.2 g/kg or 0.4 g/kg or placebo for 24 weeks. CIDP relapse was defined as ≥1-point deterioration in adjusted INCAT, with a primary endpoint of relapse or withdrawal rates. This retrospective exploratory analysis redefined relapse using I-RODS via three different cut-off methods: an individual variability method, fixed cut-off of ≥8-point deterioration on I-RODS centile score or ≥4-point deterioration on I-RODS raw score. Relapse or withdrawal rates were 47% for placebo, 34% for 0.2 g/kg IgPro20 and 19% for 0.4 g/kg IgPro20 using the raw score; 40%, 28% and 15%, respectively using the centile score, and 49%, 40% and 27%, respectively using the individual variability method. IgPro20 was shown to be efficacious as a maintenance therapy for CIDP when relapse was defined using I-RODS. A stable response pattern was shown for I-RODS across various applied cut-offs, which could be applied in future clinical trials.

TDP-43 Proteinopathy and Tauopathy: Do They Have Pathomechanistic Links?

Transactivation response DNA binding protein 43 kDa (TDP-43) and tau are major pathological proteins of neurodegenerative disorders, of which neuronal and glial aggregates are pathological hallmarks. Interestingly, accumulating evidence from neuropathological studies has shown that comorbid TDP-43 pathology is observed in a subset of patients with tauopathies, and vice versa. The concomitant pathology often spreads in a disease-specific manner and has morphological characteristics in each primary disorder. The findings from translational studies have suggested that comorbid TDP-43 or tau pathology has clinical impacts and that the comorbid pathology is not a bystander, but a part of the disease process. Shared genetic risk factors or molecular abnormalities between TDP-43 proteinopathies and tauopathies, and direct interactions between TDP-43 and tau aggregates, have been reported. Further investigations to clarify the pathogenetic factors that are shared by a broad spectrum of neurodegenerative disorders will establish key therapeutic targets.

FXTAS is difficult to differentiate from neuronal intranuclear inclusion disease through skin biopsy: a case report.

BACKGROUND: Both fragile X-associated tremor/ataxia syndrome (FXTAS) and late-onset neuronal intranuclear inclusion disease (NIID) show CGG/GGC trinucleotide repeat expansions. Differentiating these diseases are difficult because of the similarity in their clinical and radiological features. It is unclear that skin biopsy can distinguish NIID from FXTAS. We performed a skin biopsy in an FXTAS case with cognitive dysfunction and peripheral neuropathy without tremor, which was initially suspected to be NIID. CASE PRESENTATION: The patient underwent neurological assessment and examinations, including laboratory tests, electrophysiologic test, imaging, skin biopsy, and genetic test. A brain MRI showed hyperintensity lesions along the corticomedullary junction on diffusion-weighted imaging (DWI) in addition to middle cerebellar peduncle sign (MCP sign). We suspected NIID from the clinical picture and the radiological findings, and performed a skin biopsy. The skin biopsy specimen showed ubiquitin- and p62-positive intranuclear inclusions, suggesting NIID. However, a genetic analysis for NIID using repeat-primed polymerase chain reaction (RP-PCR) revealed no expansion detected in the Notch 2 N-terminal like C (NOTCH2NLC) gene. We then performed genetic analysis for FXTAS using RP-PCR, which revealed a repeat CGG/GGC expansion in the FMRP translational regulator 1 (FMR1) gene. The number of repeats was 83. We finally diagnosed the patient with FXTAS rather than NIID. CONCLUSIONS: For the differential diagnosis of FXTAS and NIID, a skin biopsy alone is insufficient; instead, genetic analysis, is essential. Further investigations in additional cases based on genetic analysis are needed to elucidate the clinical and pathological differences between FXTAS and NIID.

Nerve biopsy in acquired neuropathies.

A diagnosis of neuropathy can typically be determined through clinical assessment and focused investigation. With technological advances, including significant progress in genomics, the role of nerve biopsy has receded over recent years. However, making a specific and, in some cases, tissue-based diagnosis is essential across a wide array of potentially treatable acquired peripheral neuropathies. When laboratory investigations do not suggest a definitive diagnosis, nerve biopsy remains the final step to ascertain the etiology of the disease. The present review highlights the utility of nerve biopsy in confirming a diagnosis, while further illustrating the importance of a tissue-based diagnosis in relation to treatment strategies, particularly when linked to long-term immunosuppressive therapies.

Aberrant interaction between FUS and SFPQ in neurons in a wide range of FTLD spectrum diseases.

Fused in sarcoma (FUS) is genetically and clinicopathologically linked to frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis (ALS). We have previously reported that intranuclear interactions of FUS and splicing factor, proline- and glutamine-rich (SFPQ) contribute to neuronal homeostasis. Disruption of the FUS-SFPQ interaction leads to an increase in the ratio of 4-repeat tau (4R-tau)/3-repeat tau (3R-tau), which manifests in FTLD-like phenotypes in mice. Here, we examined FUS-SFPQ interactions in 142 autopsied individuals with FUS-related ALS/FTLD (ALS/FTLD-FUS), TDP-43-related ALS/FTLD (ALS/FTLD-TDP), progressive supranuclear palsy, corticobasal degeneration, Alzheimer's disease, or Pick's disease as well as controls. Immunofluorescent imaging showed impaired intranuclear co-localization of FUS and SFPQ in neurons of ALS/FTLD-FUS, ALS/FTLD-TDP, progressive supranuclear palsy and corticobasal degeneration cases, but not in Alzheimer's disease or Pick's disease cases. Immunoprecipitation analyses of FUS and SFPQ revealed reduced interactions between the two proteins in ALS/FTLD-TDP and progressive supranuclear palsy cases, but not in those with Alzheimer disease. Furthermore, the ratio of 4R/3R-tau was elevated in cases with ALS/FTLD-TDP and progressive supranuclear palsy, but was largely unaffected in cases with Alzheimer disease. We concluded that impaired interactions between intranuclear FUS and SFPQ and the subsequent increase in the ratio of 4R/3R-tau constitute a common pathogenesis pathway in FTLD spectrum diseases.

Arginine is a disease modifier for polyQ disease models that stabilizes polyQ protein conformation.

The polyglutamine (polyQ) diseases are a group of inherited neurodegenerative diseases that include Huntington's disease, various spinocerebellar ataxias, spinal and bulbar muscular atrophy, and dentatorubral pallidoluysian atrophy. They are caused by the abnormal expansion of a CAG repeat coding for the polyQ stretch in the causative gene of each disease. The expanded polyQ stretches trigger abnormal ß-sheet conformational transition and oligomerization followed by aggregation of the polyQ proteins in the affected neurons, leading to neuronal toxicity and neurodegeneration. Disease-modifying therapies that attenuate both symptoms and molecular pathogenesis of polyQ diseases remain an unmet clinical need. Here we identified arginine, a chemical chaperone that facilitates proper protein folding, as a novel compound that targets the upstream processes of polyQ protein aggregation by stabilizing the polyQ protein conformation. We first screened representative chemical chaperones using an in vitro polyQ aggregation assay, and identified arginine as a potent polyQ aggregation inhibitor. Our in vitro and cellular assays revealed that arginine exerts its anti-aggregation property by inhibiting the toxic ß-sheet conformational transition and oligomerization of polyQ proteins before the formation of insoluble aggregates. Arginine exhibited therapeutic effects on neurological symptoms and protein aggregation pathology in Caenorhabditis elegans, Drosophila, and two different mouse models of polyQ diseases. Arginine was also effective in a polyQ mouse model when administered after symptom onset. As arginine has been safely used for urea cycle defects and for mitochondrial myopathy, encephalopathy, lactic acid and stroke syndrome patients, and efficiently crosses the blood-brain barrier, a drug-repositioning approach for arginine would enable prompt clinical application as a promising disease-modifier drug for the polyQ diseases.

Unexpected postmortem diagnoses in cases of clinically diagnosed amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is a motor neuron disease that is clinically and pathologically characterized by impairment of the upper and lower motor neurons. The clinical diagnosis of ALS is not always straightforward because of the lack of specific biomarkers and clinical heterogeneity. This review presents the clinical and pathological findings of four autopsied cases that had been diagnosed with ALS before death. These cases had demonstrated definite and progressive motor neuron signs and symptoms, whereas postmortem assessment revealed miscellaneous disorders, including fungal infection, paraneoplastic syndrome, and amyloidosis. Importantly, nonmotor neuron signs and symptoms, including seizures, extra-pyramidal signs, ocular movement disorders, sensory disturbance, and dysautonomia, had also been documented during the disease course of the cases in the present study. The ALS-unlike symptoms were indicative of the "true" diagnosis in each case when those symptoms were isolated from motor neuron signs/symptoms.