The wide-ranging clinical and genetic features in Japanese families with valosin-containing protein proteinopathy.

Mutations in the valosin-containing protein (VCP) gene are known to cause various neurodegenerative disorders. Here, we report 8 Japanese patients [6 men, 2 women; median age at onset: 49.5 (range, 35-58) years] from 5 unrelated families with VCP missense mutations. Although 7 of 8 patients were diagnosed with either inclusion body myopathy or amyotrophic lateral sclerosis, 1 patient showed demyelinating polyneuropathy, which was confirmed by longitudinal nerve conduction studies. Sural nerve biopsy of the patient revealed intranuclear ubiquitin staining in Schwann cells. Three known pathogenic VCP mutations (p.Arg191Gln, p.Arg155Cys, and p.Ile126Phe) were detected. A novel mutation, c.293 A>T (p.Asp98Val), was also identified in a patient with amyotrophic lateral sclerosis and frontotemporal dementia. This mutation was predicted to be "deleterious" or "disease causing" using in silico mutation analyses. In conclusion, demyelinating polyneuropathy may be a novel phenotype caused by VCP mutations. The p.Asp98Val mutation was found to be a novel pathogenic mutation of VCP proteinopathy. We believe our cases represent a wide clinical spectrum of VCP mutations.

Genetic and functional analysis of KIF5A variants in Japanese patients with sporadic amyotrophic lateral sclerosis.

Two recent genetic studies reported that loss-of-function mutation of the C-terminal cargo-binding tail domain of the KIF5A gene cause amyotrophic lateral sclerosis (ALS). The aim of this study is to investigate the frequency of KIF5A variants in Japanese patients with sporadic ALS. In total, 807 sporadic ALS patients and 191 normal controls from a multicenter ALS cohort in Japan were included. Whole exome sequencing on an Illumina HiSeq 2000/2500 sequencer was used to identify and select variants within the KIF5A gene. Thirteen patients harbored a nonsynonymous variant in the KIF5A gene; These were considered variants of uncertain significance. One patient harbored a novel splice-site variant (c.2993-3C>A) in the C-terminal cargo-binding tail domain of the KIF5A gene. Functional analysis of this variant revealed that it caused skipping of exon 27. The frequency of KIF5A mutations in Japanese patients with sporadic ALS was 0.12% (1/807). This study reports a novel loss-of-function variant in KIF5A, and indicates that loss-of-function variant in KIF5A is a rare cause of sporadic ALS in Japanese patients.

The relationships between three-axis accelerometer measures of physical activity and motor symptoms in patients with Parkinson's disease: a single-center pilot study.

BACKGROUND: Various wearable devices for objectively evaluating motor symptoms of patients with Parkinson's disease (PD) have been developed. Importantly, previous studies have suggested protective effects of physical activity in PD. However, the relationships between conventional clinical ratings for PD and three-axis accelerometer measures of physical activity (e.g., daily physical activity levels [PAL] or metabolic equivalents of task [METs]) are still unclear, particularly for METs. In the current study, we sought to elucidate these relationships on a daily basis, and to clarify optimal predictors for clinical states on a 30-min basis. METHODS: Patients who were hospitalized for adjustment of drugs or deep brain stimulation were enrolled. Using waist-worn three-axis accelerometers, PAL and METs parameter data were obtained and compared with UPDRS-3[On] and symptom diary data. We extracted data from the patients' best and worst days, defined by the best and worst UPDRS-3[On] scores, respectively. Thus, 22 data sets from 11 patients were extracted. We examined the correlations and produced scatter plots to represent the relationships, then investigated which METs parameters and activity patterns were the best predictors for "On" and "dyskinesia". RESULTS: The parameter "mean METs value within the 95-92.5 percentile range on a day (95-92.5 percentile value)" exhibited the strongest correlation with conventional daily clinical ratings (Rho: - 0.799 for UPDRS-3[On], 0.803 for On hours [p < 0.001]). Scatter plots suggested that PAL tended to have higher values in patients with involuntary movement. However, METs parameters focusing on higher METs seemed to alleviate this tendency. We clarified that "time over 2.0 METs" and "time over 1.5 METs" could be predictors for "On" and "dyskinesia" on a 30-min basis, respectively (AUROC: 0.779 and 0.959, 95% CI: 0.733-0.824 and 0.918-1.000). The specificity and sensitivity of the optimal activity pattern for "On" were 0.858 and 0.621. CONCLUSIONS: This study suggested feasible activity patterns and METs parameters for objective evaluation of motor symptoms on a 30-min or daily basis. Three-axis accelerometer measures focusing on higher METs may be appropriate for evaluating physical activity. Further larger-scale studies are necessary to clarify the validity, reliability, and clinical utility of these objective measures.

A multi-ethnic meta-analysis identifies novel genes, including ACSL5, associated with amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is a devastating progressive motor neuron disease that affects people of all ethnicities. Approximately 90% of ALS cases are sporadic and thought to have multifactorial pathogenesis. To understand the genetics of sporadic ALS, we conducted a genome-wide association study using 1,173 sporadic ALS cases and 8,925 controls in a Japanese population. A combined meta-analysis of our Japanese cohort with individuals of European ancestry revealed a significant association at the ACSL5 locus (top SNP p = 2.97 × 10-8). We validated the association with ACSL5 in a replication study with a Chinese population and an independent Japanese population (1941 ALS cases, 3821 controls; top SNP p = 1.82 × 10-4). In the combined meta-analysis, the intronic ACSL5 SNP rs3736947 showed the strongest association (p = 7.81 × 10-11). Using a gene-based analysis of the full multi-ethnic dataset, we uncovered additional genes significantly associated with ALS: ERGIC1, RAPGEF5, FNBP1, and ATXN3. These results advance our understanding of the genetic basis of sporadic ALS.

Prognosis of amyotrophic lateral sclerosis patients undergoing tracheostomy invasive ventilation therapy in Japan.

OBJECTIVE: The aim of this study is to describe and clarify the factors affecting the prognosis of Japanese patients with amyotrophic lateral sclerosis (ALS) undergoing tracheostomy invasive ventilation (TIV) therapy. METHODS: We conducted a prospective longitudinal observational case-control study using a multicentre registry. ALS patients who started TIV therapy after registration (TIV group) and those who did not receive TIV (non-TIV group) were included. We compared the survival time between the TIV group and the non-TIV group using a propensity score matching analysis and evaluated the prognostic factors in the TIV group. RESULTS: From February 2006 to January 2018, 190 patients in the TIV group and 1093 patients in the non-TIV group were included in this study. The mean age of disease onset and usage rate of gastrostomy and non-invasive ventilation therapy differed between the groups. In the propensity score matching analysis using known prognostic factors, the median overall survival time of the TIV group was significantly greater than that of the non-TIV group (11.33 years vs 4.61 years; p<0.001). Analysis using the Cox proportional hazard model suggested that older age of onset and respiratory onset was an independent factor for poor prognosis after starting TIV therapy. CONCLUSION: We showed that there was a significant difference of approximately 7 years in life expectancy between Japanese ALS patients who did and did not receive TIV therapy.

Increase of arginine dimethylation correlates with the progression and prognosis of ALS.

OBJECTIVE: To investigate whether arginine methylation is altered in patients with amyotrophic lateral sclerosis (ALS) and how it affects disease severity, progression, and prognosis. METHODS: We compared the immunoreactivity of protein arginine methyltransferase 1 (PRMT1) and its products, asymmetric dimethylated proteins (ASYM), in postmortem spinal cord. We also measured the concentrations of total l-arginine and methylated arginine residues, including asymmetric dimethyl l-arginine (ADMA), symmetric dimethyl arginine, and monomethyl arginine, in CSF samples from 52 patients with ALS using liquid chromatography-tandem mass spectrometry, and we examined their relationship with the progression and prognosis of ALS. RESULTS: The immunoreactivity of both PRMT1 (p < 0.0001) and ASYM (p = 0.005) was increased in patients with ALS. The concentration of ADMA in CSF was substantially higher in patients with ALS than in disease controls. The ADMA/l-arginine ratio was correlated with the change of decline in the ALS Functional Rating Scale at 12 months after the time of measurement (r = 0.406, p = 0.010). A Cox proportional hazards model showed that the ADMA/l-arginine ratio was an independent predictor for overall survival. Moreover, a high ADMA/l-arginine ratio predicted poor prognosis, even in a group with normal percentage forced vital capacity. CONCLUSION: There was an enhancement of arginine dimethylation in patients with ALS, and the ADMA/l-arginine ratio predicted disease progression and prognosis in such patients.

Frequency and characteristics of the TBK1 gene variants in Japanese patients with sporadic amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is a devastating neurological disease, and the etiology of sporadic ALS is generally unknown. The TANK-binding kinase 1 (TBK1) gene was identified as an ALS gene contributing to a predisposition toward ALS. To reveal the frequency and characteristics of variants of the TBK1 gene in sporadic ALS patients in Japan, we analyzed the TBK1 gene by exome sequencing in a large Japanese cohort of 713 sporadic ALS patients and 800 controls. We identified known or potentially toxic rare variants of TBK1 gene in 9 patients (1.26%) with sporadic ALS, including 4 novel missense variants (p.V23I, p.H322R, p.R358C, and p.T478I) and 3 loss-of-function variants (p.R357X, p.P378_I379del, and p.T419_G420del). The odds ratio between sporadic ALS patients and controls was 10.2 (p = 0.008, 95% confidence interval = 1.67-62.47). These findings support the contribution of TBK1 to the etiology of sporadic ALS in Japanese patients.

Structural MRI correlates of amyotrophic lateral sclerosis progression.

PURPOSE: Amyotrophic lateral sclerosis (ALS) presents with varying degrees of brain degeneration that can extend beyond the corticospinal tract (CST). Furthermore, the clinical course and progression of ALS varies widely. Brain degeneration detected using structural MRI could reflect disease progression. SUBJECTS AND METHODS: On study registration, 3-Tesla volumetric MRI and diffusion tensor imaging scans were obtained at baseline in 38 healthy controls and 67 patients with sporadic ALS. Patients had Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised (ALSFRS-R) scores of ≥36 and did not have the chromosome 9, open reading frame 72 repeat expansion. Six months later, changes in ALSFRS-R (ΔALSFRS-R) scores were calculated and patients were grouped into three categories, namely, patients with slow progression with ΔALSFRS-R scores ≤3 (n=19), intermediate progression with ΔALSFRS-R scores =4, 5 and 6 (n=36) and rapid progression with ΔALSFRS-R scores ≥7 (n=12). We analysed voxel-based morphometry and tract-based spatial statistics among these subgroups and controls. RESULTS: In comparison with controls, patients with ALS showed grey matter atrophy and decreased fractional anisotropy beyond the motor cortex and CST, especially in the frontotemporal lobes and basal ganglia. Moreover, the degree of change was highly proportional to ΔALSFRS-R at the 6-month assessment. CONCLUSION: A more rapid disease progression and poorer functional decline were associated with greater involvement of the extra-motor cortex and basal ganglia, suggesting that the spatial extent of brain involvement can be an indicator of the progression in ALS.

Age of onset differentially influences the progression of regional dysfunction in sporadic amyotrophic lateral sclerosis.

The clinical courses of sporadic amyotrophic lateral sclerosis (ALS) show extensive variability. Our objective was to elucidate how age of onset influences the progression of regional symptoms and functional losses in sporadic ALS. We included 648 patients with sporadic ALS from a multicenter prospective ALS cohort. We investigated the distribution of initial symptoms and analyzed the time from onset to events affecting activities of daily living (ADL) as well as the longitudinal changes in each regional functional rating score among four groups with different ages of onset. The frequencies of dysarthria and dysphagia as initial symptoms were higher in the older age groups, whereas weakness of upper limbs was the most common initial symptom in the youngest age group. The survival times and the times from onset to loss of speech and swallowing were significantly shorter in the older age group (p < 0.001), although the times from onset to loss of upper limb function were not significantly different among the age groups. According to joint modeling analysis, the bulbar score declined faster in the older age groups (<50 vs. 60-69 years: p = 0.029, <50 vs. ≥70 years: p < 0.001), whereas there was no significant correlation between the age of onset and decline in the upper limb score. Our results showed that age of onset had a significant influence on survival time and the progression of bulbar symptoms, but had no influence on upper limb function in sporadic ALS.

A rapid functional decline type of amyotrophic lateral sclerosis is linked to low expression of TTN.

OBJECTIVE: To classify the patterns of functional decline in patients with sporadic amyotrophic lateral sclerosis (ALS) and explore the genetic backgrounds that modified these patterns. METHODS: We included 465 patients with sporadic ALS in the analysis and clustered the longitudinal functional scores in the registered patients, using a mixture approach of a non-linear mixed-effects model. We conducted a genome-wide analysis of 572 983 single nucleotide polymorphisms (SNPs). We then assessed the association between the clusters of longitudinal functional scores and SNPs. RESULTS: We identified the following four clusters of longitudinal functional decline in the cases: a rapid decline cluster, an intermediate decline cluster, a sigmoidal decline cluster and a moderate decline cluster. We identified seven SNPs associated with the rapid decline cluster, using a recessive model (p=3.47-8.34×10(-8)). The OR for the probabilities of the rapid decline cluster ranged from 5.5 to 5.84. Homozygosity for the minor alleles in the seven SNPs, which constituted a linkage disequilibrium (LD) block, was associated with decreased expression of TTN (encoding Titin, a large sarcomere protein) in the expression quantitative trait loci database of a large-scale Japanese genetic variation database (p=8.6×10(-10)-1.1×10(-7)). TTN expression in immortalised lymphocyte lines was decreased in patients who were homozygous for the minor alleles compared with those who were homozygous for the major alleles (n=19 in each group, p=0.002). CONCLUSIONS: We detected an LD block associated with a rapid functional decline in patients with sporadic ALS, which is linked to decreased expression of TTN.

Next-generation sequencing of 28 ALS-related genes in a Japanese ALS cohort.

We investigated the frequency and contribution of variants of the 28 known amyotrophic lateral sclerosis (ALS)-related genes in Japanese ALS patients. We designed a multiplex, polymerase chain reaction-based primer panel to amplify the coding regions of the 28 ALS-related genes and sequenced DNA samples from 257 Japanese ALS patients using an Ion Torrent PGM sequencer. We also performed exome sequencing and identified variants of the 28 genes in an additional 251 ALS patients using an Illumina HiSeq 2000 platform. We identified the known ALS pathogenic variants and predicted the functional properties of novel nonsynonymous variants in silico. These variants were confirmed by Sanger sequencing. Known pathogenic variants were identified in 19 (48.7%) of the 39 familial ALS patients and 14 (3.0%) of the 469 sporadic ALS patients. Thirty-two sporadic ALS patients (6.8%) harbored 1 or 2 novel nonsynonymous variants of ALS-related genes that might be deleterious. This study reports the first extensive genetic screening of Japanese ALS patients. These findings are useful for developing genetic screening and counseling strategies for such patients.