[Charcot-Marie-Tooth disease Patient Registry in Japan].

To clarify the natural courses, medical conditions, and problems in daily life and medical care of the patients with Charcot-Marie-Tooth disease (CMT) in Japan, we have developed a patient registration system (CMT Patient Registry (CMTPR)). We analyzed data of questionnaires from 303 patients (males: 162, females: 141, mean age: 45.9 years old) who registered for CMTPR. The age of onset was less than 15 years old in 45% and more than 60 years old in 5% of the patients. Genetic testing was performed in 65%, and about half of the patients with genetic testing had a duplication of the PMP22 gene. Seventy-six percent of the patients had regular visits to medical facilities. Five percent of patients had no history of hospital visits. Fifteen percent of all patients needed assistance with daily activities due to motor function impairment in the upper extremities, and 25% required assistance due to lower limb impairment. There were no significant differences in the need for assistance by gender or age. Of the 267 adult patients, 18% had difficulty working due to reasons related to the disease, although none of the junior patients reported any problem attending school. This was the first nationwide epidemiological study with healthcare and welfare information on patients with CMT in Japan. We hope the results of this study will lead to better welfare and medical care in CMT patients.

Serum leucine-rich α2 glycoprotein as a potential biomarker for systemic inflammation in Parkinson's disease.

There is ample epidemiological and animal-model evidence suggesting that intestinal inflammation is associated with the development of Parkinson's disease (PD). Leucine-rich α2 glycoprotein (LRG) is a serum inflammatory biomarker used to monitor the activity of autoimmune diseases, including inflammatory bowel diseases. In this study, we aimed to investigate whether serum LRG could be used a biomarker of systemic inflammation in PD and to help distinguish disease states. Serum LRG and C-reactive protein (CRP) levels were measured in 66 patients with PD and 31 age-matched controls. We found that serum LRG levels were statistically significantly higher in the PD group than in the control group (PD: 13.9 ± 4.2 ng/mL, control: 12.1 ± 2.7 ng/mL, p = 0.036). LRG levels were also correlated with Charlson comorbidity index (CCI) and CRP levels. LRG levels in the PD group were correlated with Hoehn and Yahr stages (Spearman's r = 0.40, p = 0.008). LRG levels were statistically significantly elevated in PD patients with dementia as compared to those without dementia (p = 0.0078). Multivariate analysis revealed a statistically significant correlation between PD and serum LRG levels after adjusting for serum CRP levels, and CCI (p = 0.019). We conclude that serum LRG levels could be considered a potential biomarker for systemic inflammation in PD.

Compound muscle action potential duration ratio for differentiation between Charcot-Marie-Tooth disease and CIDP.

OBJECTIVE: To elucidate the utility of the proximal to distal compound muscle action potential (CMAP) duration ratio to distinguish between demyelinating Charcot-Marie-Tooth disease (CMT) and chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) compared with nerve ultrasound. METHODS: Thirty-nine demyelinating CMT patients and 19 CIDP patients underwent nerve conduction studies (NCS) and nerve ultrasound. NCS parameters including CMAP duration ratio calculated by dividing the value at the proximal site by that at the distal site and nerve cross-sectional area (CSA) measured by ultrasound were compared between the two groups. The diagnostic sensitivity and specificity of each parameter were analysed. RESULTS: CMT patients showed a significantly lower CMAP duration ratio than CIDP patients (p < 0.05). The area under the curve (AUC) value of the CMAP duration ratio exceeded 0.95 when CMT was considered "positive", and a cut-off value of 1.13 resulted in high diagnostic sensitivity and specificity (84.6 and 100 % for median nerve, 97.4 and 85.7 % for ulnar nerve, respectively), whereas the AUC value of nerve CSA ranged from 0.70 to 0.81. CONCLUSIONS: The CMAP duration ratio could effectively distinguish between demyelinating CMT and CIDP. SIGNIFICANCE: Adding the CMAP duration ratio to a routine NCS may improve the accuracy of the diagnosis of demyelinating CMT.

Amyotrophic lateral sclerosis: Correlations between fluid biomarkers of NfL, TDP-43, and tau, and clinical characteristics.

OBJECTIVES: We previously reported the diagnostic and prognostic performance of neurofilament light chain (NfL), TAR DNA-binding protein 43 (TDP-43), and total tau (t-tau) in cerebrospinal fluid (CSF) and plasma as amyotrophic lateral sclerosis (ALS) biomarkers. The present study aimed to elucidate associations between clinical characteristics and the markers as well as mutual associations of the markers in ALS patients using the same dataset. METHODS: NfL, TDP-43, and t-tau levels in CSF and plasma in 75 ALS patients were analyzed. The associations between those markers and clinical details were investigated by uni- and multivariate analyses. Correlations between the markers were analyzed univariately. RESULTS: In multivariate analysis of CSF proteins, the disease progression rate (DPR) was positively correlated with NfL (ß: 0.51, p = 0.007) and t-tau (ß: 0.37, p = 0.03). Plasma NfL was correlated with age (ß: 0.53, p = 0.005) and diagnostic grade (ß: -0.42, p = 0.02) in multivariate analysis. Plasma TDP-43 was correlated negatively with split hand index (ß: -0.48, p = 0.04) and positively with % vital capacity (ß: 0.64, p = 0.03) in multivariate analysis. Regarding mutual biomarker analysis, a negative correlation between CSF-NfL and TDP-43 was identified (r: -0.36, p = 0.002). CONCLUSIONS: Elevated NfL and t-tau levels in CSF may be biomarkers to predict rapid DPR from onset to sample collection. The negative relationship between CSF NfL and TDP-43 suggests that elevation of CSF TDP-43 in ALS is not a simple consequence of its release into CSF during neurodegeneration. The negative correlation between plasma TDP-43 and split hand index may support the pathophysiological association between plasma TDP-43 and ALS.

Impaired age-dependent increases in phosphoglycerate kinase activity in red blood cells of Parkinson's disease patients.

BACKGROUND: Impaired bioenergetics are partially involved in the pathogenesis of Parkinson's disease (PD). Phosphoglycerate kinase (PGK), an essential enzyme for glycolysis, has recently attracted attention due to its pathogenic role in PD and as a target for disease-modifying therapies. This study is aimed to evaluate the profiles of PGK activity in red blood cells (RBCs) of PD patients and controls. METHODS: Sixty-eight PD patients and thirty-four age-matched unrelated controls were enrolled. PGK activities of RBCs were measured by the established colorimetric assay and standardized by the same RBC samples. RESULTS: PGK activity of the PD group was significantly higher than that of the control group in participants aged sixty-five years or younger, whereas it was not significantly different between the two groups at any age. PGK activity was positively correlated with aging in the control group, but this was not noted in the PD group. On multivariable analysis by partial correlation in the PD group, PGK activity was negatively correlated with the specific binding ratio of dopamine transporter scintigraphy in the striatum. The levodopa-equivalent daily dose was not significantly correlated with the enzyme activity. CONCLUSION: The results support the following: 1) elevation of PGK activities in RBCs can be detected in relatively young PD patients and with normal aging; 2) the degree of striatonigral degeneration is associated with elevated PGK activities. These are important considerations when the PGK assay is applied as a diagnostic biomarker of PD and to therapeutically monitor PGK-enhancing treatments.

Drosophila as a Model for Microbiota Studies of Neurodegeneration.

Accumulating evidence show that the gut microbiota is deeply involved not only in host nutrient metabolism but also in immune function, endocrine regulation, and chronic disease. In neurodegenerative conditions such as Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis, the gut-brain axis, the bidirectional interaction between the brain and the gut, provides new route of pathological spread and potential therapeutic targets. Although studies of gut microbiota have been conducted mainly in mice, mammalian gut microbiota is highly diverse, complex, and sensitive to environmental changes. Drosophila melanogaster, a fruit fly, has many advantages as a laboratory animal: short life cycle, numerous and genetically homogenous offspring, less ethical concerns, availability of many genetic models, and low maintenance costs. Drosophila has a simpler gut microbiota than mammals and can be made to remain sterile or to have standardized gut microbiota by simple established methods. Research on the microbiota of Drosophila has revealed new molecules that regulate the brain-gut axis, and it has been shown that dysbiosis of the fly microbiota worsens lifespan, motor function, and neurodegeneration in AD and PD models. The results shown in fly studies represents a fundamental part of the immune and proteomic process involving gut-microbiota interactions that are highly conserved. Even though the fly's gut microbiota are not simple mimics of humans, flies are a valuable system to learn the molecular mechanisms of how the gut microbiota affect host health and behavior.

High-density surface electromyography to assess motor unit firing rate in Charcot-Marie-Tooth disease type 1A patients.

OBJECTIVE: The aim of this study was to elucidate the characteristics of the motor unit (MU) firing rate in Charcot-Marie-Tooth disease type 1A (CMT1A) patients and its longitudinal change using high-density surface-electromyography (surface-EMG) and MU decomposition analysis. METHODS: Nineteen patients with CMT1A and 21 force-matched healthy controls prospectively underwent surface-EMG recording of the vastus lateralis muscle during ramp-up and sustained contractions on performing isometric knee extension. After decomposition analysis, instantaneous firing rates (IFRs) of individually identified MUs were calculated. In CMT1A patients, follow-up measurements were performed one year after the baseline. Comparison of IFRs and clinical variables between CMT1A patients and controls at the baseline and between the baseline and after one year in CMT1A patients was performed. RESULTS: Mean IFRs of MUs were lower in CMT1A patients than in controls. This was true at various force levels in ramp-up contractions (p < 0.01. e.g., 10.3 (CMT1A patients) vs. 12.2 (controls) pulses-per-second (pps) at 22.5-27.5% of maximal voluntary contraction (MVC) in MUs recruited at <7.5% of MVC) and at any time-point during sustained contractions (p < 0.001. e.g., 8.0 vs. 9.3 pps, respectively, at 10-20 seconds). In CMT1A patients, mean IFRs at 0-10 seconds of sustained contraction were significantly decreased over one year (from 8.06 to 7.52 pps; p = 0.027), whereas the disease severity score and MVC of knee extension did not change over time. CONCLUSION: CMT1A patients had a lower individual MU firing rate. SIGNIFICANCE: The MU firing rate is a potential short-term biomarker of axonal damage in CMT1A patients.

Risk factors for neuropsychiatric symptoms in patients with Parkinson's disease during COVID-19 pandemic in Japan.

The worsening of neuropsychiatric symptoms such as depression, anxiety, and insomnia in patients with Parkinson's disease (PD) has been a concern during the COVID-19 pandemic, because most people worked in self-isolation for fear of infection. We aimed to clarify the impact of social restrictions imposed due to the COVID-19 pandemic on neuropsychiatric symptoms in PD patients and to identify risk factors associated with these symptoms. A cross-sectional, hospital-based survey was conducted from April 22, 2020 to May 15, 2020. PD patients and their family members were asked to complete paper-based questionnaires about neuropsychiatric symptoms by mail. PD patients were evaluated for motor symptoms using MDS-UPDRS part 2 by telephone interview. A total of 71 responders (39 PD patients and 32 controls) completed the study. Although there was no difference in the age distribution, the rate of females was significantly lower in PD patients (35%) than controls (84%) (P < 0.001). Participants with clinical depression (PHQ-9 score ≥ 10) were more common in PD patients (39%) than controls (6%) (P = 0.002). Multivariate logistic regression analysis revealed that an MDS-UPDRS part 2 score was correlated with the presence of clinical depression (PHQ-9 score ≥ 10) and clinical anxiety (GAD-7 score ≥ 7) (clinical depression: OR, 1.31; 95% CI, 1.04-1.66; P = 0.025; clinical anxiety: OR, 1.36; 95% CI, 1.07-1.72; P = 0.013). In the presence of social restrictions, more attention needs to be paid to the neuropsychiatric complications of PD patients, especially those with more severe motor symptoms.

Recent Advances in Drosophila Models of Charcot-Marie-Tooth Disease.

Charcot-Marie-Tooth disease (CMT) is one of the most common inherited peripheral neuropathies. CMT patients typically show slowly progressive muscle weakness and sensory loss in a distal dominant pattern in childhood. The diagnosis of CMT is based on clinical symptoms, electrophysiological examinations, and genetic testing. Advances in genetic testing technology have revealed the genetic heterogeneity of CMT; more than 100 genes containing the disease causative mutations have been identified. Because a single genetic alteration in CMT leads to progressive neurodegeneration, studies of CMT patients and their respective models revealed the genotype-phenotype relationships of targeted genes. Conventionally, rodents and cell lines have often been used to study the pathogenesis of CMT. Recently, Drosophila has also attracted attention as a CMT model. In this review, we outline the clinical characteristics of CMT, describe the advantages and disadvantages of using Drosophila in CMT studies, and introduce recent advances in CMT research that successfully applied the use of Drosophila, in areas such as molecules associated with mitochondria, endosomes/lysosomes, transfer RNA, axonal transport, and glucose metabolism.

Charcot-Marie-Tooth disease type 1A: Longitudinal change in nerve ultrasound parameters.

BACKGROUND: This study aimed to elucidate the longitudinal changes in nerve ultrasound parameters of adult Charcot-Marie-Tooth disease type 1A (CMT1A) patients. METHODS: Fifteen adult patients with CMT1A prospectively underwent nerve ultrasound and clinical assessment (CMT neuropathy score [CMTNS]) at baseline and 5 y later. Nerve cross-sectional area (CSA) and echogenicity were measured in the median and sural nerves. Changes in ultrasound parameters and CMTNS and correlation between changes of ultrasound parameters and CMTNS were analyzed. RESULTS: Median and sural nerve CSAs did not change over 5 y, although CMTNS increased (P < .01). Nerve echogenicity in the sural nerve decreased over 5 y (P = .045). No correlations between changes in nerve ultrasound parameters and CMTNS were identified. CONCLUSIONS: No longitudinal changes in nerve size was detected in adult CMT1A. Exploring the factors that determine nerve size in childhood CMT1A may lead to the development of treatments.

Rate of Changes in CMT Neuropathy and Examination Scores in Japanese Adult CMT1A Patients.

Introduction: We aimed to clarify when adult patients with Charcot-Marie-Tooth disease type 1A (CMT1A), especially those diagnosed at middle or advanced ages, first showed symptoms and whether the rate of disease progression is accelerated by aging. Methods: Medical records of CMT1A outpatients between 2012 and 2019 were reviewed. The age at diagnosis, age when symptoms first appeared, and rate of disease progression, assessed based on clinical outcome measures including the CMT Neuropathy Score (CMTNS), Rasch-modified CMTNS (CMTNS-R), CMT Examination Score (CMTES), and Rasch-modified CMTES (CMTES-R) were analyzed. Results: Among 45 adult CMT1A patients, 42% had been diagnosed after 50 years of age, whereas 91% of all patients had exhibited some CMT-related symptoms before 20 years of age. The annual increase of all clinical outcome measures did not differ between patients under and over 50 years. Even when limited to patients whose initial CMTES-R showed mild to moderate severity, the rate of change in CMTES-R did not differ between the two age groups (the annual mean ± standard deviation, under 50 years: 1.1 ± 1.0, and over 50 years: 0.9 ± 1.1, p = 0.68). To determine whether patients with disabilities at a young age have a higher deterioration rate, they were classified into three groups according to their current age and age at diagnosis: patients under 50 years of age, patients over 50 years of age but diagnosed before 50, and patients diagnosed after 50 years of age. The mean annual increase of all clinical outcome measures, however, did not differ among these groups (CMTES-R: 1.03 ± 1.01 vs. 0.94 ± 1.57 vs. 0.81 ± 0.88, respectively, p = 0.87). Discussion: CMT1A patients develop symptoms in childhood and adolescence even if such symptoms are not noticeable until reaching an advanced age. Deterioration rates of clinical outcome measures are constant irrespective of the age in their adulthood, although we cannot rule out the limitation that the difference did not reach significance because of the small number of patients. Being aware of the existence of a considerable number of undiagnosed CMT patients will help promote the avoidance of inadequate medication.

Quantification of Blood Caffeine Levels in Patients With Parkinson's Disease and Multiple System Atrophy by Caffeine ELISA.

Caffeine is considered to be a neuroprotective agent against Parkinson's disease (PD) and is expected to offer a blood-based biomarker for the disease. We herein investigated the ability of this biomarker to discriminate between PD and neurodegenerative diseases. To quantify caffeine concentrations in serum and plasma, we developed a specific competitive enzyme-linked immunosorbent assay (ELISA). To validate the diagnostic performance of the assay, we conducted a case control-study of two independent cohorts among controls and patients with PD and multiple system atrophy (MSA). Parallelism, recovery rate, and intra- and inter-assay precision of our assay were within the standard of acceptance. In the first cohort of 31 PD patients, 18 MSA patients and 33 age-matched controls, serum caffeine levels were significantly lower in PD patients than in Controls (p = 0.018). A similar trend was also observed in the MSA group, but did not reach the level of significance. In the second cohort of 50 PD patients, 50 MSA patients and 45 age-matched controls, plasma caffeine levels were significantly decreased in both PD and MSA groups compared to Controls (p < 0.001). This originally developed ELISA offered sufficient sensitivity to detect caffeine in human serum and plasma. We reproducibly confirmed decreased blood concentrations of caffeine in PD compared to controls using this ELISA. A similar trend was observed in the MSA group, despite a lack of consistent significant differences across cohorts.

Combined use of CSF NfL and CSF TDP-43 improves diagnostic performance in ALS.

OBJECTIVE: To determine the diagnostic and prognostic significance of neurofilament light chain (NfL), TAR DNA-binding protein 43 (TDP-43), and total tau (t-tau) in cerebrospinal fluid (CSF) and plasma of patients with amyotrophic lateral sclerosis (ALS) and to investigate whether the combined use of those biomarker candidates can improve their diagnostic performance. METHODS: This was a single-center, prospective, longitudinal study. CSF and plasma samples were collected at the time of enrollment from a discovery cohort of 29 patients with ALS and 29 age-matched controls without neurodegenerative disease. In a validation cohort, there were 46 patients with ALS, and 46 control (not age-matched) patients with motor weakness resulting from neuromuscular diseases. NfL, TDP-43, and t-tau levels in CSF and plasma were measured using ultrasensitive single molecule assay (Simoa) technology. RESULTS: The following findings were reproducibly observed among the discovery and validation cohorts: increased levels of CSF NfL, plasma NfL, and CSF TDP-43 in ALS compared with control groups; shorter survival associated with higher levels of CSF and plasma NfL. When the CSF NfL and CSF TDP-43 levels were combined, the areas under the ROC curves (AUC) were slightly improved relative to AUCs for each biomarker alone. INTERPRETATION: CSF and plasma NfL may not only serve as diagnostic biomarkers but also provide a measure of disease progression. CSF TDP-43 is also useful as a diagnostic biomarker of ALS, but has no prognostic value. The combined use of CSF NfL and CSF TDP-43 may be a useful biomarker for the diagnosis of ALS.

Cancer-Associated Hypercoagulation Increases the Risk of Early Recurrent Stroke in Patients with Active Cancer.

BACKGROUND: This study assessed the incidence and predictors of short-term stroke recurrence in ischemic stroke patients with active cancer, and elucidated whether cancer-associated hypercoagulation is related to early recurrent stroke. METHODS: We retrospectively enrolled acute ischemic stroke patients with active cancer admitted to our hospital between 2006 and 2017. Active cancer was defined as diagnosis or treatment for any cancer within 12 months before stroke onset, known recurrent cancer or metastatic disease. The primary clinical outcome was recurrent ischemic stroke within 30 days. RESULTS: One hundred ten acute ischemic stroke patients with active cancer (73 men, age 71.3 ± 10.1 years) were enrolled. Of those, recurrent stroke occurred in 12 patients (11%). When patients with and without recurrent stroke were compared, it was found that those with recurrent stroke had a higher incidence of pancreatic cancer (33 vs. 10%), systemic metastasis (75 vs. 39%), multiple vascular territory infarctions (MVTI; 83 vs. 40%), and higher -D-dimer levels (16.9 vs. 2.9 µg/mL). Multivariable logistic regression analysis showed that each factor mentioned above was not significantly associated with stroke recurrence independently, but high D-dimer (hDD) levels (≥10.4 µg/mL) and MVTI together were significantly associated with stroke recurrence (OR 6.20, 95% CI 1.42-30.7, p = 0.015). CONCLUSIONS: Ischemic stroke patients with active cancer faced a high risk of early recurrent stroke. The concurrence of hDD levels (≥10.4 µg/mL) and MVTI was an independent predictor of early recurrent stroke in active cancer patients. Our findings suggest that cancer-associated hypercoagulation increases the early recurrent stroke risk.

Analysis of neural crest cells from Charcot-Marie-Tooth disease patients demonstrates disease-relevant molecular signature.

Charcot-Marie-Tooth disease (CMT) is the most common inherited neuropathy. The majority of CMT is demyelinating type (demyelinating CMT) caused by Schwann cell involvement. Although a large number of genes responsible for demyelinating CMT have been found, the common molecular target of the pathophysiology caused by these different genes in demyelinating CMT is still unknown. We generated induced pluripotent stem cells (iPSCs) from healthy controls and patients with demyelinating CMT caused by duplication in peripheral myelin protein 22 kDa (PMP22) or point mutations in myelin protein zero (MPZ) or early growth response 2 (EGR2). iPSCs were differentiated into neural crest cells, progenitors of Schwann cells, followed by purification using the neural crest cell markers p75 and human natural killer-1. To identify a disease-relevant molecular signature at the early stage of demyelinating CMT, we conducted global gene expression analysis of iPSC-derived neural crest cells and found that a glutathione-mediated detoxification pathway was one of the related pathways in demyelinating CMT. mRNA expression of glutathione S-transferase theta 2 (GSTT2), encoding an important enzyme for glutathione-mediated detoxification, and production of reactive oxygen species were increased in demyelinating CMT. Our study suggested that patient-iPSC-derived neural crest cells could be a cellular model for investigating genetically heterogeneous disease CMT and might provide a therapeutic target for the disease.

Parasympathetic Dominant Autonomic Dysfunction in Charcot-Marie-Tooth Disease Type 2J with the MPZ Thr124Met Mutation.

We herein report the case of a 69-year-old woman with Charcot-Marie-Tooth Disease type 2J (CMT2J) who presented with Adie's pupil, deafness, and urinary disturbance in addition to motor symptoms. On autonomic investigation, the coefficient of variation of the R-R intervals was decreased, and a urodynamic analysis showed a hypotonic bladder. A heart rate variability analysis revealed a decreased high frequency component and low frequency/high frequency ratio. Orthostatic hypotension was not present, and the sympathetic skin response and cardiac scintigraphy using (123)I-metaiodobenzylguanidine were normal. A gene analysis showed a known heterozygous mutation associated with CMT2J in myelin protein zero exon 3, resulting in the substitution of threonine to methionine at position 124. Our case suggests that mainly the parasympathetic autonomic function is disturbed in CMT2J.

Hereditary diffuse leukoencephalopathy with spheroids characterized by spastic hemiplegia preceding mental impairment.

Hereditary diffuse leukoencephalopathy with spheroids (HDLS) is a young-adult-onset autosomal dominant white matter disease characterized by progressive cognitive dysfunction. We herein report the case of a 20-year-old woman who developed spastic hemiplegia. Brain magnetic resonance imaging revealed increased bilateral T2 signal intensity and bright diffusion-weighted imaging signals with a low apparent diffusion coefficient within the frontoparietal white matter. The lesion gradually expanded for over one year. The patient was initially diagnosed with multiple sclerosis (MS); however, she did not respond to immunosuppressive therapy. DNA sequencing showed a heterozygous c.2381T>C mutation in colony-stimulating factor 1 receptor. HDLS with a pure motor phenotype is sometimes difficult to differentiate from MS.