Prevalence of repeat expansions causing autosomal dominant spinocerebellar ataxias in Hokkaido, the northernmost island of Japan.

In Japan, approximately 30% of spinocerebellar degeneration (SCD) is hereditary, and more than 90% of hereditary SCD is autosomal dominant SCD (AD-SCD). We have previously reported the types of AD-SCD in Hokkaido, twice. In this study, we investigated the status of AD-SCD mainly due to repeat expansions, covering the period since the last report. We performed genetic analysis for 312 patients with a clinical diagnosis of SCD, except for multiple system atrophy at medical institutions in Hokkaido between January 2007 and December 2020. The median age at the time of analysis was 58 (1-86) years. Pathogenic variants causing AD-SCD due to repeat expansion were found in 61.5% (192 cases). Spinocerebellar ataxia (SCA) 6 was the most common type in 25.3% (79 cases), followed by Machado-Joseph disease (MJD)/SCA3 in 13.8% (43), SCA1 in 6.4% (20), SCA2 in 5.1% (16), SCA31 in 4.8% (15), dentatorubral-pallidoluysian atrophy in 4.8% (15), SCA7 in 0.6% (2), and SCA8 in 0.6% (2). SCA17, 27B, 36, and 37 were not found. Compared to previous reports, this study found a higher prevalence of SCA6 and a lower prevalence of MJD/SCA3. An increasing number of cases identified by genetic testing, including cases with no apparent family history, accurately revealed the distribution of disease types in Hokkaido.

Complete nanopore repeat sequencing of SCA27B (GAA-FGF14 ataxia) in Japanese.

BACKGROUND: Although pure GAA expansion is considered pathogenic in SCA27B, non-GAA repeat motif is mostly mixed into longer repeat sequences. This study aimed to unravel the complete sequencing of FGF14 repeat expansion to elucidate its repeat motifs and pathogenicity. METHODS: We screened FGF14 repeat expansion in a Japanese cohort of 460 molecularly undiagnosed adult-onset cerebellar ataxia patients and 1022 controls, together with 92 non-Japanese controls, and performed nanopore sequencing of FGF14 repeat expansion. RESULTS: In the Japanese population, the GCA motif was predominantly observed as the non-GAA motif, whereas the GGA motif was frequently detected in non-Japanese controls. The 5'-common flanking variant was observed in all Japanese GAA repeat alleles within normal length, demonstrating its meiotic stability against repeat expansion. In both patients and controls, pure GAA repeat was up to 400 units in length, whereas non-pathogenic GAA-GCA repeat was larger, up to 900 units, but they evolved from different haplotypes, as rs534066520, located just upstream of the repeat sequence, completely discriminated them. Both (GAA)≥250 and (GAA)≥200 were enriched in patients, whereas (GAA-GCA)≥200 was similarly observed in patients and controls, suggesting the pathogenic threshold of (GAA)≥200 for cerebellar ataxia. We identified 14 patients with SCA27B (3.0%), but their single-nucleotide polymorphism genotype indicated different founder alleles between Japanese and Caucasians. The low prevalence of SCA27B in Japanese may be due to the lower allele frequency of (GAA)≥250 in the Japanese population than in Caucasians (0.15% vs 0.32%-1.26%). CONCLUSIONS: FGF14 repeat expansion has unique features of pathogenicity and allelic origin, as revealed by a single ethnic study.

Gait video-based prediction of unified Parkinson's disease rating scale score: a retrospective study.

BACKGROUND: The diagnosis of Parkinson's disease (PD) and evaluation of its symptoms require in-person clinical examination. Remote evaluation of PD symptoms is desirable, especially during a pandemic such as the coronavirus disease 2019 pandemic. One potential method to remotely evaluate PD motor impairments is video-based analysis. In this study, we aimed to assess the feasibility of predicting the Unified Parkinson's Disease Rating Scale (UPDRS) score from gait videos using a convolutional neural network (CNN) model. METHODS: We retrospectively obtained 737 consecutive gait videos of 74 patients with PD and their corresponding neurologist-rated UPDRS scores. We utilized a CNN model for predicting the total UPDRS part III score and four subscores of axial symptoms (items 27, 28, 29, and 30), bradykinesia (items 23, 24, 25, 26, and 31), rigidity (item 22) and tremor (items 20 and 21). We trained the model on 80% of the gait videos and used 10% of the videos as a validation dataset. We evaluated the predictive performance of the trained model by comparing the model-predicted score with the neurologist-rated score for the remaining 10% of videos (test dataset). We calculated the coefficient of determination (R2) between those scores to evaluate the model's goodness of fit. RESULTS: In the test dataset, the R2 values between the model-predicted and neurologist-rated values for the total UPDRS part III score and subscores of axial symptoms, bradykinesia, rigidity, and tremor were 0.59, 0.77, 0.56, 0.46, and 0.0, respectively. The performance was relatively low for videos from patients with severe symptoms. CONCLUSIONS: Despite the low predictive performance of the model for the total UPDRS part III score, it demonstrated relatively high performance in predicting subscores of axial symptoms. The model approximately predicted the total UPDRS part III scores of patients with moderate symptoms, but the performance was low for patients with severe symptoms owing to limited data. A larger dataset is needed to improve the model's performance in clinical settings.

Elderly patients with suspected Charcot-Marie-Tooth disease should be tested for the TTR gene for effective treatments.

BACKGROUND AND AIMS: Some hereditary transthyretin (ATTRv) amyloidosis patients are misdiagnosed as Charcot-Marie-Tooth disease (CMT) at onset. We assess the findings to identify ATTRv amyloidosis among patients with suspected CMT to screen transthyretin gene variants for treatments. METHODS: We assessed clinical, cerebrospinal fluid, and electrophysiological findings by comparing ATTRv amyloidosis patients with suspected CMT (n = 10) and CMT patients (n = 489). RESULTS: The median (interquartile range) age at onset of neurological symptoms was 69 (64.2-70) years in the ATTRv amyloidosis vs 12 (5-37.2) years in CMT group (Mann-Whitney U, p < 0.01). The proportion of patients with initial sensory symptoms was 70% in the ATTRv amyloidosis group vs 7.1% in CMT group (Fisher's exact, p < 0.01). The proportion of patients with histories of suspected chronic inflammatory demyelinating polyneuropathy (CIDP) were 50% in the ATTRv amyloidosis group vs 8.7% in CMT group (Fisher's exact, p < .01). Other measures and outcomes were not different between the two groups. Five of the six patients with ATTRv amyloidosis received treatment and survived. INTERPRETATION: For effective treatments, the transthyretin gene should be screened in patients with suspected CMT with old age at onset of neurological symptoms, initial sensory symptoms, and histories of suspected CIDP.

A diagnostic index based on quantitative susceptibility mapping and voxel-based morphometry may improve early diagnosis of Alzheimer's disease.

OBJECTIVES: Voxel-based morphometry (VBM) is widely used to quantify the progression of Alzheimer's disease (AD), but improvement is still needed for accurate early diagnosis. We evaluated the feasibility of a novel diagnosis index for early diagnosis of AD based on quantitative susceptibility mapping (QSM) and VBM. METHODS: Thirty-seven patients with AD, 24 patients with mild cognitive impairment (MCI) due to AD, and 36 cognitively normal (NC) subjects from four centers were included. A hybrid sequence was performed by using 3-T MRI with a 3D multi-echo GRE sequence to obtain both a T1-weighted image for VBM and phase images for QSM. The index was calculated from specific voxels in QSM and VBM images by using a linear support vector machine. The method of voxel extraction was optimized to maximize diagnostic accuracy, and the optimized index was compared with the conventional VBM-based index using receiver operating characteristic analysis. RESULTS: The index was optimal when voxels were extracted as increased susceptibility (AD > NC) in the parietal lobe and decreased gray matter volume (AD < NC) in the limbic system. The optimized proposed index showed excellent performance for discrimination between AD and NC (AUC = 0.94, p = 1.1 × 10-10) and good performance for MCI and NC (AUC = 0.87, p = 1.8 × 10-6), but poor performance for AD and MCI (AUC = 0.68, p = 0.018). Compared with the conventional index, AUCs were improved for all cases, especially for MCI and NC (p < 0.05). CONCLUSIONS: In this preliminary study, the proposed index based on QSM and VBM improved the diagnostic performance between MCI and NC groups compared with the VBM-based index. KEY POINTS: • We developed a novel diagnostic index for Alzheimer's disease based on quantitative susceptibility mapping (QSM) and voxel-based morphometry (VBM). • QSM and VBM images can be acquired simultaneously in a single sequence with little increasing scan time. • In this preliminary study, the proposed diagnostic index improved the discriminative performance between mild cognitive impairment and normal control groups compared with the conventional VBM-based index.

Adrenoleukodystrophy siblings with a novel ABCD1 missense variant presenting with phenotypic differences: a case report and literature review.

Adrenoleukodystrophy (ALD) is an X-linked disease that affects primarily the white matter of the central nervous system and adrenal cortex. A correlation between genotypes and phenotypes has not been observed. Here, we present two Japanese siblings with a novel missense variant (c.1887T > G) in the ABCD1 gene who presented with different clinical phenotypes, i.e., adolescent cerebral and cerebello-brainstem types. We also review the literature focusing on the variation in the clinical phenotypes within ALD families. In our review, 61.9% of sibling pairs presented with the same clinical type of ALD and 59.1% of sibling pairs presented with a similar age of onset. Conversely, 15.4% of sibling pairs had a similar age of onset, but different clinical types of ALD. To observe the correlation between genotypes and phenotypes, it is important to diagnose early and to accumulate reports describing age of onset, first onset symptom, and progression of the symptom.

Progressive multifocal leukoencephalopathy with mild clinical conditions and detection of archetype-like JC virus in cerebrospinal fluid.

Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease of the central nervous system with a poor prognosis and is primarily caused by JC virus (JCV) with a mutation called prototype. We encountered a case of PML with moderate progression and analyzed the mutational patterns of JCV in the cerebrospinal fluid (CSF). A 19-year-old Japanese woman with mild neurological symptoms was diagnosed with combined immunodeficiency following pneumocystis pneumonia. Brain magnetic resonance imaging scan showed multiple brain lesions, and real-time polymerase chain reaction testing detected JCV in the CSF, leading to the diagnosis of PML. The disease course of PML was stable after administration of mefloquine and mirtazapine with immunoglobulin replacement therapy. In the JCV genome cloned from the patient CSF, DNA sequences of the gene encoding the capsid protein (VP1) and the non-coding control region exhibited small mutations. However, they were quite similar to those of the archetype JCV, which persists asymptomatically in healthy individuals. These findings provide insight into the mutational characteristics of JCV in PML with mild symptoms and progression.

Correlation of active contact location with weight gain after subthalamic nucleus deep brain stimulation: a case series.

BACKGROUND: Weight gain (WG) is a frequently reported side effect of subthalamic deep brain stimulation; however, the underlying mechanisms remain unclear. The active contact locations influence the clinical outcomes of subthalamic deep brain stimulation, but it is unclear whether WG is directly associated with the active contact locations. We aimed to determine whether WG is associated with the subthalamic deep brain stimulation active contact locations. METHODS: We enrolled 14 patients with Parkinson's disease who underwent bilateral subthalamic deep brain stimulation between 2013 and 2019. Bodyweight and body mass index were measured before and one year following the surgery. The Lead-DBS Matlab toolbox was used to determine the active contact locations based on magnetic resonance imaging and computed tomography. We also created sweet spot maps for WG using voxel-wise statistics, based on volume of tissue activation and the WG of each patient. Fluorodeoxyglucose-positron emission tomography data were also acquired before and one year following surgery, and statistical parametric mapping was used to evaluate changes in brain metabolism. We examined which brain regions' metabolism fluctuation significantly correlated with increased body mass index scores and positron emission tomography data. RESULTS: One year after surgery, the body mass index increase was 2.03 kg/m2. The sweet spots for WG were bilateral, mainly located dorsally outside of the subthalamic nucleus (STN). Furthermore, WG was correlated with increased metabolism in the left limbic and associative regions, including the middle temporal gyrus, inferior frontal gyrus, and orbital gyrus. CONCLUSIONS: Although the mechanisms underlying WG following subthalamic deep brain stimulation are possibly multifactorial, our findings suggest that dorsal stimulation outside of STN may lead to WG. The metabolic changes in limbic and associative cortical regions after STN-DBS may also be one of the mechanisms underlying WG. Further studies are warranted to confirm whether dorsal stimulation outside of STN changes the activities of these cortical regions.

Investigating the role of genetic counseling in neuromuscular disease considering life events.

Genetic diagnoses are becoming a routine in the medical practice of neuromuscular diseases. Many diagnoses, however, can have an influence on relatives and family members and thus must be handled carefully by genetic counseling (GC). Here, we aimed to assess the purpose of undergoing GC to verify the utility of collaborations between clinical and genetic divisions. We investigated consecutive GC cases of neuromuscular disease and examined the role of GC. Our study included 102 cases who underwent GC in our hospital from July 2005 to March 2018: 86.3% were women and 45.1% were in their 30's. Disease explanation was the most common reason for attending GC (29.4%), followed by prenatal diagnosis (25.5%), pre-symptomatic diagnosis (17.6%), and carrier diagnosis (14.7%). Clients typically visited the hospital for GC when some kind of life event occurred, such as marriage, had a desire to bear a child, or a change in the condition of the proband. Clinicians should be conscious of such life events from the perspective of both the client and their relatives, and guide the GC at an appropriate time. Overall, the degree of recognition of genetic risk by clients differed; thus, it is important for GC to determine the status of each unique situation and respond individually.

The Responsiveness of Triaxial Accelerometer Measurement of Gait Ataxia Is Higher than That of the Scale for the Assessment and Rating of Ataxia in the Early Stages of Spinocerebellar Degeneration.

We reported previously that the average medial-lateral gait amplitude while walking on a straight path determined using triaxial accelerometers fixed on the middle of the upper back may be a quantitative and concise indicator for the severity of cerebellar ataxia. Considering that gait ataxia is a typical initial symptom in a variety of spinocerebellar degeneration (SCD), we aimed to develop quantitative biomarkers for cerebellar ataxia as metric variables. We used triaxial accelerometers to analyze gait parameters in 14 patients with SCD at 3 points over 3 years (at baseline, 1.5 years and 3 years). Analysis of covariance (ANCOVA) models adjusted for the baseline scores were used to estimate sample sizes. The mean medial-lateral amplitude (ML) gained by a triaxial accelerometer fixed on upper back could detect the each 1.5-year change. In the 14 patients, the mean ML(m) was 0.032 ± 0.007(SD) at entry, 0.037 ± 0.008 after 1.5-year follow, and 0.042 ± 0.020 after 3-year follow. In contrast, SARA gait scores were 2.9, 2.9, and 3.0, respectively. The responsiveness of the quantitative evaluation of gait ataxia by triaxial accelerometers is higher than that of the SARA within a 1.5-year follow-up period. Gait analysis by triaxial accelerometers will be complementary to the evaluation of scales like SARA in the assessment of clinical severity of SCD patients in early stage.

Comparison of Different Symptom Assessment Scales for Multiple System Atrophy.

To identify the most sensitive scale for use in clinical trials on multiple system atrophy (MSA), a short and sensitive scale is needed for MSA clinical trials. Potential candidates are the Unified MSA Rating Scale (UMSARS), Scale for the Assessment and Rating of Ataxia (SARA), Berg Balance Scale (BBS), MSA Health-Related Quality of Life scale (MSA-QoL), and Scales for Outcomes in Parkinson's Disease-Autonomic questionnaire (SCOPA-AUT). We enrolled patients with MSA from eight hospitals in Hokkaido, Japan. Board-certified neurologists assessed each patient at 6-month intervals and scored them on the UMSARS, SARA, BBS, MSA-QoL, and SCOPA-AUT. Score changes were evaluated using the standardized response mean (SRM). The correlation between disease duration and each score was examined. The first evaluation was conducted on 85 patients (60 patients with MSA cerebellar ataxia dominant subtype [MSA-C] and 25 patients with MSA Parkinsonism-dominant subtype [MSA-P]). Sixty-nine patients were examined after 6 months and 63 patients after 12 months. The UMSARS Part 4 had the largest SRM after 6 months and the SARA after 12 months. SRMs for MSA-P, the shorter duration group, and the early-onset group were larger than were those for MSA-C, the longer duration group, and the late-onset group. SRMs for items regarding skilled hand activities, walking, and standing were relatively large. Our study indicates that the UMSARS (parts 2 and 4), SARA, and BBS are sensitive scales for evaluating MSA progression over 12 months. Items with large SRMs effectively evaluated short-term changes.

Epidemiology of Multiple System Atrophy in Hokkaido, the Northernmost Island of Japan.

Multiple system atrophy (MSA) is an intractable neurodegenerative disorder that is characterized by various combinations of autonomic failure, cerebellar ataxia, and parkinsonism. We conducted an epidemiological study of MSA using the combined data of a national registry system and a postal survey in Hokkaido, Japan. A postal survey was conducted in 2013 based on national registry data from 2006 to 2011. This survey contained the current status of each patient with MSA that had been collected from attending physicians and recorded into a national registry. Survey items included date, outcomes, primary symptoms, and activities of daily living at the last medical examination. Confirmation data of the diagnosis by a board-certified neurologist was also collected. Based on the national registry data, 1,092 patients with MSA were selected as our target population. The response rate of the postal survey was 81% (885/1,092). After excluding inappropriate responses, 839 patients with MSA were analyzed. Forty-nine percent of the patients were male, and the mean onset age was 62.1 ± 10.4 years. A Kaplan-Meier survival curve revealed that patients with onset symptoms of cerebellar ataxia had a better prognosis than those with onset of parkinsonism or autonomic failure (p < 0.01). Additionally, we found that a higher onset age was associated with poor prognosis. We found that patients with cerebellar ataxia at onset had a better survival prognosis than those with parkinsonism or autonomic failure at onset and that patients with an older age at onset had a worse survival prognosis.

Reliability of the unified multiple system atrophy rating scale using the telephone.

OBJECTIVE: The unified multiple system atrophy rating scale (UMSARS) was used to evaluate various symptoms of multiple system atrophy (MSA). And UMSARS part 1 was originally developed for use in interviews, but the need for telemedicine is increasing in COVID-19 pandemic. The purpose of this study is to evaluate the reliability of the UMSARS part 1 telephone survey. METHODS: Thirty-two MSA patients took the UMSARS part 1 face-to-face, followed by two more telephone evaluations. Intraclass correlation coefficients (ICC) and Cronbach's alpha (α) coefficients were calculated, and the inter-rater reliability was determined. At the same time, we asked about the problems in COVID-19 pandemic. RESULTS: The study participants included 15 men and 17 women with mean age of 67.1 years (SD, 8.3). For the total UMSARS part 1 score, the inter-rater ICC and Cronbach's α coefficient were 0.89 to 0.92, and 0.84 to 0.87, respectively. More than half of the items had a relatively high ICC. Cronbach's α coefficients were more than 0.7 for all items. Changes that occurred in COVID-19 pandemic included reduced outings and lack of rehabilitation in about half of the cases. CONCLUSION: The UMSARS part 1 has high inter-rater reliability and internal consistency. Evaluation of subjective symptoms showed that some variability could occur. In addition, there was concern about the influence of lack of rehabilitation due to COVID-19 pandemic.

The Movement Disorder Society Criteria: Its Clinical Usefulness in Multiple System Atrophy.

Objective In 2022, Wenning et al. proposed the Movement Disorder Society Criteria (MDS Criteria) for the Diagnosis of Multiple System Atrophy (MSA). These criteria were expected to provide useful alternatives to the second consensus statement. We examined trends in these diagnostic criteria. Methods We used patient data registered with the Hokkaido Rare Disease Consortium for Multiple System Atrophy, which has been recruiting patients with MSA through medical facilities in Hokkaido since November 2014. Patients were evaluated according to the MDS criteria based on neurological examinations and imaging findings at three separate times: the first evaluation, the time of enrollment (diagnosis), and the most recent evaluation (final evaluation). Results The MDS criteria were examined in 68 of 244 patients enrolled between November 2014 and July 2022. At the initial evaluation, the classifications were as follows: clinically established (n=27; 39.7%); clinically probable (n=13; 19.1%); possible prodromal (n=12; 17.6%); and negative (did not meet criteria (n=16; 23.5%). At the time of diagnosis, the classifications were as follows: clinically established (n=45; 66.2%); clinically probable (n=12; 17.6%); possible prodromal (n=4; 5.9%); and negative (n=7; 10.3%). At the final evaluation, the classifications were as follows: clinically established (n=52; 76.5%); clinically probable (n=9; 13.2%); possible prodromal (n=2; 2.9%); and negative (n=5; 7.4%). Conclusions We were able to clarify the changes in the criteria values and transition of patients due to the clarification of imaging and supportive findings in the MDS criteria.

[New MDS Criteria for the Diagnosis of Multiple System Atrophy: How to Use in Clinical Practice and Clinical Trials].

The newly revised diagnostic criteria for multiple system atrophy (MSA) have reduced the criteria for diagnosing orthostatic hypotension compared to the conventional diagnostic criteria, but require tests such as MRI and residual urine measurement. Under the new diagnostic criteria, cases that were previously classified as possible MSA with low diagnostic accuracy may become clinically established with higher diagnostic accuracy. However, examination of the cohort treated in our establishment showed that there were cases in which the diagnostic criteria could not be applied when the symptoms and test items necessary for diagnosis were not confirmed. In clinical trials, clinically established or clinically probable MSA are targeted for interventional studies, and possible prodromal MSA are considered to be more important for observational studies. In the future, it will be necessary to confirm the diagnostic accuracy pathologically, accumulate evidence from various clinical tests that are listed as supportive biomarkers, and to develop more useful diagnostic criteria.

[Treatment for Spinocerebellar Degeneration].

No disease-modifying therapy has been established for spinocerebellar degeneration and multiple system atrophy, and only symptomatic therapy is currently available. Taltirelin and protirelin are drugs covered by health insurance for cerebellar ataxia symptoms, and are expected to suppress the progression of symptoms. Muscle relaxants are used for spasticity associated with spinocerebellar degeneration, and vasopressors and therapeutic agents for dysuria are used for autonomic symptoms of multiple system atrophy. It is necessary to develop a new therapeutic agent with a different mechanism of action, aimed specifically at modifying the disease progression in patients with spinocerebellar degeneration and multiple system atrophy.

[Diagnosis of cryoglobulinemic vasculitis based on B symptoms and peripheral neuropathy: a case report].

A man in his 50s presented with a 2-month history of paresthesia and hypoesthesia of the extremities and B symptoms including low-grade fever, weight loss, and night sweats. He also reported a 3-year history of skin discoloration in cold weather. Laboratory test results showed a high white blood cell count and elevated serum C-reactive protein and rheumatoid factor (RF) levels. Complement levels were low, and tests for cryoglobulin showed positive results. Computed tomography revealed generalized lymphadenopathy, and 18F-fluorodeoxyglucose-positron emission tomography showed increased uptake; therefore, we performed cervical lymph node and muscle biopsies. The patient was diagnosed with nodular marginal zone lymphoma and cryoglobulinemic vasculitis (CV) and received chemotherapy and steroid treatment with improvement in symptoms. CV is a rare immune complex small-vessel vasculitis. It is important to measure RF and complement levels and consider infections, collagen diseases, and hematological disorders in the differential diagnosis in patients with suspected vasculitis or CV.

Practice of Hereditary ATTR Amyloidosis in Non-endemic Areas of Japan.

Objective Hereditary ATTR (ATTRv) amyloidosis was once an incurable disease; however, in recent years, disease-modifying therapies, such as tafamidis and patisiran, have become available. We herein report the medical care situation in an ATTRv amyloidosis non-endemic area of Japan. Methods We confirmed the information in the medical records of our department and analyzed the data retrospectively. Patients Patients with ATTRv amyloidosis who were treated in our department between 2010 and 2021 were included. Results A total of 15 ATTRv amyloidosis cases (8 men and 7 women) were treated in our department during the study period; 9 patients had a family history, and the transthyretin V30M (p.V50M) gene mutation was present in 66% of cases. The average age of the onset was 57 years old, with 73% of the initial symptoms being dysesthesia and 13% being autonomic dysfunction. Ten patients were treated with tafamidis and nine with patisiran. Although it took a long time to start treatment among our experienced cases, there were some cases in which treatment could be introduced relatively early. Conclusion ATTRv amyloidosis is treatable and should be included in the differential diagnosis of neuropathy so that it can be diagnosed early and introduced into treatment. In the near future, the presymptomatic diagnosis of ATTRv amyloidosis and genetic counseling will become more important.