Investigation of Glucose Metabolism by Continuous Glucose Monitoring and Validation of Dipeptidyl Peptidase 4 Inhibitor Use in Patients with Myotonic Dystrophy Type 1.

Objectives: We characterized blood glucose fluctuations in patients with myotonic dystrophy type 1 (DM1). After confirming the incretin secretion capacity of patients with DM1, we intended to clarify whether dipeptidyl peptidase 4 (DPP-4) inhibitor administration was appropriate in cases of DM1 with diabetes mellitus. Methods: A 48 h continuous glucose monitoring (CGM) was performed in 29 Japanese patients with DM1. An oral glucose tolerance test (OGTT) was performed in patients with DM1 and five disease controls, and levels of blood glucose, insulin, and incretin (glucagon-like peptide-1 and gastric inhibitory polypeptide) were measured. DPP-4 inhibitors were administered to patients with diabetes mellitus complicated by DM1, and the CGM results were compared. Results: The CGM showed distinct patterns of blood glucose variability among patients classified by an OGTT pattern with significant differences in glucose parameters such as time above 140 mg/dL and mean amplitude of glycemic excursions between the groups. High sensor glucose values were observed in a certain number of patients who were classified as having normal or impaired glucose tolerance by the OGTT. The CGM confirmed the presence of low glucose levels in several patients. Incretin secretion, the target of DPP-4 inhibitors, was preserved in patients with DM1. DPP-4 inhibitor treatment resulted in lower glucose levels and improved insulin secretion in some patients. Conclusions: This is the first CGM study for DM1 patients. The CGM identified potential early abnormalities in glucose metabolism in DM1. In the future, it will be crucial to explore effective methods for harnessing CGM and assessing it quantitatively in DM1.

Analysis of Corneal Phenotypes in Japanese Patients With Myotonic Dystrophy Type 1.

PURPOSE: To analyze the corneal phenotypes of Japanese patients with myotonic dystrophy type 1 (DM1). METHODS: We included patients with DM1 who were diagnosed with clinical neuromuscular symptoms by neurologists and CTG trinucleotide repeat (TNR) expansion of the (myotonic dystrophy protein kinase) DMPK gene. We analyzed the corneal phenotype using slit-lamp examination, specular microscopy, and anterior segment optical coherence tomography. We evaluated TNR expansion in the TCF4 gene of leukocyte-derived genomic DNA by fragment analysis using polymerase chain reaction and triplet-repeat primed polymerase chain reaction. RESULTS: Nineteen eyes from 10 patients with DM1 (DM1 group) and 72 eyes from 37 healthy participants (control group) were analyzed. The average age was 49.3 ± 11.9 and 51.8 ± 12.9 years in the DM1 and control groups, respectively (P = 0.11). Slit-lamp examination demonstrated that 2 patients with DM1 had bilateral corneal guttae equivalent to modified Krachmer grade 1 of Fuchs endothelial corneal dystrophy. Dark areas on specular microscopy were observed in 4 of 19 eyes (21.1%) and 0 of 72 eyes (0%) in the DM1 and control groups, respectively, with statistically significant differences (P = 0.002). The average endothelial cell density in the DM1 group (3536 ± 722 cells/mm2) was significantly higher than that in the control group (3026 ± 412 cells/mm2) (P = 0.0006). TNR expansion in TCF4 was not detected in eyes with corneal guttae or in the dark areas in the DM1 group. CONCLUSIONS: Japanese patients with DM1 without TNR expansion in TCF4 have a mild phenotype equivalent to Fuchs endothelial corneal dystrophy. Endothelial cell density is higher in DM1 patients than in normal participants.

Hydrops fetalis due to loss of function of hNav1.4 channel via compound heterozygous variants.

Hydrops fetalis, characterized by abnormal fluid accumulation in fetuses, presents a significant risk of stillbirth and neonatal mortality. Although the etiology of nonimmune hydrops fetalis (NIHF) is multifaceted, recent studies have highlighted genetic factors as crucial determinants. This study focused on a family with three consecutive stillbirths, each with pronounced hydrops fetalis. Using whole-exome sequencing (WES), we identified compound heterozygous variants of the SCN4A gene encoding the voltage-gated sodium channel of the skeletal muscle (hNav1.4), c.2429T>A p.L810Q and c.4556T>C p.F1519S, in all three deceased infants. A functional analysis conducted using the whole-cell patch-clamp technique revealed loss-of-function defects in both variant channels, with F1519S exhibiting a complete loss of ionic current and L810Q showing a reduced channel opening. These findings support the pathogenicity of SCN4A variants in NIHF and underscore the significance of functional studies in elucidating genotype-phenotype correlations. Furthermore, our study emphasizes the diagnostic value of WES in cases of NIHF in where standard genetic testing fails to identify causative variants.

Combination Therapy of Lenvatinib and Hepatic Arterial Infusion Chemotherapy Using Cisplatin With Lipiodol and 5-Fluorouracil: A Potential Breakthrough Therapy for Unresectable Advanced Hepatocellular Carcinoma.

INTRODUCTION: In 2021, the LEOPARD trial reported that the combination of lenvatinib+one-shot cisplatin infusion might contribute to improving the results of conventional advanced hepatocellular carcinoma (HCC) treatment. Thus, combination therapy with lenvatinib and catheterization has emerged as a focal point in treating advanced HCC. Conversely, the New FP regimen consists of low-dose cisplatin (CDDP) combined with 5-fluorouracil (5-FU) and lipiodol via hepatic arterial infusion chemotherapy (HAIC), with a high response rate of approximately 70%. Therefore, lenvatinib+New FP (LEN-New FP) may be a more promising treatment for HCC. Here, we report six patients who were administered LEN+New FP and achieved high therapeutic efficacy. Among them, one case had an interesting clinical course, which has been described in detail. MATERIALS AND METHODS: This study included six patients who were administered 12 mg or 8 mg of lenvatinib once daily based on a body weight of ≥60 kg or <60 kg, respectively, along with 50 mg of cisplatin in 5-10 mL lipiodol, and a continuous infusion of 5-FU (1500 mg/5 days) infused every 2-4 weeks. Tumor evaluations were performed 4-8 weeks after the initiation of New FP administration and every 8-12 weeks thereafter. RESULTS: The median patient age was 65 years. All patients had a history of prior treatment with atezolizumab and bevacizumab and one of the factors associated with poor overall survival for New FP monotherapy, such as a maximum tumor diameter ≥7 cm and bilobular multifocal distribution. Four (67%) patients had severe vascular invasion. The best objective response and disease control rates were 83% and 100%, respectively. The best response of the target lesion was complete remission in four out of six patients. CONCLUSION: The LEN-New FP combination for advanced HCC showed a high response rate and was more effective in high-risk patients with factors associated with poor overall survival than that reported with conventional New FP monotherapy. Additionally, LEN-New FP exhibited extremely high objective response and disease control rates and was well tolerated, including in cases where it was considered second- or third-line systemic chemotherapy for advanced HCC. Thus, LEN-New FP can serve as a breakthrough therapy for advanced HCC based on appropriate case selection.

Worsening of myasthenic symptoms associated with statins.

INTRODUCTION/AIMS: The common presentations of statin intolerance are muscle-specific symptoms. Although statins are one type of drug reported to cause myasthenic worsening, myasthenic worsening has not been recognized as statin intolerance. The purpose of the present study is to investigate in a large cohort the safety profiles of statins in patients with myasthenia gravis (MG). METHODS: A total of 1710 consecutive patients with MG who visited sites associated with the Japan MG registry 2021 group between April and October 2021 were reviewed. Statin-associated myasthenic worsening was defined as worsening of any myasthenic symptoms on statin use and improvement of the symptom by stopping the statin or by undertaking additional treatment with patient and doctor confirmation. RESULTS: Among the 400 patients who used statins, 8 (2%) patients experienced statin intolerance and 6 (1.5%) patients experienced myasthenic worsening. No patients developed MG on the statin. Ptosis was a main symptom of myasthenic worsening in 4 (67%) patients. Atorvastatin was used in all patients with statin-associated myasthenic worsening. The symptoms of statin intolerance and statin-associated myasthenic worsening were improved within 2 months and 3 months, respectively, in all patients by cessation of statin use. DISCUSSION: Regarding statin-associated myasthenic worsening, prevalence was low, and severity was mild; with cessation of statin use, symptoms improved within a few months, and outcomes were generally good. Although statins can be used in MG patients with little concern, statin-associated myasthenic worsening should be noted in addition to the classical statin intolerance associated with statin use.

Lineage tracing using Wnt2b-2A-CreERT2 knock-in mice reveals the contributions of Wnt2b-expressing cells to novel subpopulations of mesothelial/epicardial cell lineages during mouse development.

Mesothelial and epicardial cells give rise to various types of mesenchymal cells via epithelial (mesothelial)-to-mesenchymal transition during development. However, the genes controlling the differentiation and diversification of mesothelial/epicardial cells remain unclear. Here, we examined Wnt2b expression in the embryonic mesothelium and epicardium and performed lineage tracing of Wnt2b-expressing cells by using novel Wnt2b-2A-CreERT2 knock-in and LacZ-reporter mice. Wnt2b was expressed in mesothelial cells covering visceral organs, but the expression was restricted in their subpopulations. Wnt2b-expressing cells labeled at embryonic day (E) 10.5 were distributed to the mesothelium and mesenchyme in the lungs, abdominal wall, stomach, and spleen in Wnt2b2A-CreERT2/+;R26RLacZ/+ mice at E13.0. Wnt2b was initially expressed in the proepicardial organ (PEO) at E9.5 and then in the epicardium after E10.0. Wnt2b-expressing PEO cells labeled at E9.5 differentiated into a small fraction of cardiac fibroblasts and preferentially localized at the left side of the postnatal heart. LacZ+ epicardium-derived cells labeled at E10.5 differentiated into a small fraction of fibroblasts and smooth muscle cells in the postnatal heart. Taken together, our results reveal novel subpopulations of PEO and mesothelial/epicardial cells that are distinguishable by Wnt2b expression and elucidate the unique contribution of Wnt2b-expressing PEO and epicardial cells to the postnatal heart.

Switching disease-modifying therapies from sphingosine-1-phosphate receptor modulators to natalizumab or dimethyl fumarate restores immune responses after SARS-CoV-2 mRNA vaccination in patients with multiple sclerosis.

OBJECTIVES: This study aimed to evaluate whether switching disease-modifying therapies (DMTs) from sphingosine-1 phosphate (S1P) receptor modulators to either natalizumab (NTZ) or dimethyl fumarate (DMF) could restore the effectiveness of SARS-CoV-2 mRNA vaccination in patients with multiple sclerosis (MS). METHODS: This study included 9 controls and 33 patients with MS: 7 patients treated with DMF, 7 patients treated with NTZ, 9 patients treated with S1P receptor modulators, and 10 patients who had switched DMTs from S1P receptor modulators to DMF or NTZ by the second vaccine dose. The patients who had switched DMTs were classified into two groups, based on whether their lymphocyte counts were above or below 1000/µL at the time of vaccination. In addition, relapses within 6 months after switching DMTs were also evaluated in these patients. Six months after the second dose of the vaccination, anti-SARS-CoV-2 spike antibodies were evaluated in all participants, and spike specific CD4+ T cells were also assessed in patients who had switched DMTs from S1P receptor modulators. RESULTS: Patients treated with S1P receptor modulators had lower levels of anti-SARS-CoV-2 spike antibodies than the controls and patients treated with DMF and NTZ. On the other hand, in patients who had switched DMTs from S1P receptor modulators, a recovery of lymphocyte counts above 1000/µL resulted in restored humoral and cellular immune responses to the vaccination. There were no neurological relapses in patients who had switched DMTs from S1P receptor modulators to NTZ. CONCLUSION: SARS-CoV-2 mRNA vaccination is expected to be effective in patients whose lymphocyte counts have recovered due to switching DMTs from S1P receptor modulators. Switching DMTs from S1P receptor modulators to NTZ before vaccination may be beneficial in achieving efficacy for SARS-CoV-2 mRNA vaccination, with a reduced risk of relapse.

Taste disorders and alopecia in myasthenia gravis.

BACKGROUND: Non-motor symptoms in myasthenia gravis (MG) are rarely confirmed. Although there are some small cohort studies, a large-systemic survey has not yet been performed. METHODS: We investigated the incidence and clinical characteristics of patients with MG who had taste disorders and alopecia using data of 1710 patients with MG enrolled in the Japan MG Registry 2021. RESULTS: Among them, 104 (6.1%) out of 1692 patients and 138 (8.2%) out of 1688 patients had histories of taste disorders and alopecia, respectively. Among the patients with MG, taste disorders were significantly more common in women, those with severe symptoms, refractory MG, or thymoma-associated MG, and were less common in those with ocular MG. The taste disorders often occurred after the onset of MG and often responded to MG treatments. Alopecia was more common in MG patients with a history of bulbar palsy and thymoma, and it often occurred before the onset of MG and sometimes responded to MG treatments. Multivariate logistic regression analysis revealed taste disturbance was associated with worst quantitative MG score and thymoma-associated MG; and alopecia was associated with thymoma-associated MG. CONCLUSION: Clinicians should be aware of the non-motor symptoms in MG, especially in patients with severe myasthenic symptoms and thymoma-associated MG.

Real-world experience with eculizumab and switching to ravulizumab for generalized myasthenia gravis.

OBJECTIVE: Eculizumab and ravulizumab are complement protein C5 inhibitors, showing efficacy and tolerability for patients with anti-acetylcholine receptor-positive (AChR+) generalized myasthenia gravis (gMG) in phase 3 clinical trials and subsequent analyses. The purpose of the present study was to evaluate the clinical significance of eculizumab and switching to ravulizumab for refractory AChR+ gMG patients in the real-world experience. METHODS: Among the database of Japan MG registry survey 2021, we studied AChR+ gMG patients who received eculizumab. We also evaluated these patients who switched from eculizumab to ravulizumab. Responder was defined as an improvement of at least 3 points in MG-ADL. We performed a questionnaire of preference between eculizumab and ravulizumab. RESULTS: Among 1,106 patients with AChR+ gMG, 36 patients (3%) received eculizumab (female 78%, mean age 56.0 years). Eculizumab was preferentially used in severe and refractory MG patients. The duration of eculizumab treatment was 35 months on average. MG-ADL improved from 9.4 ± 4.9 to 5.9 ± 5.1, and 25 (70%) of the 36 gMG patients were responders. Postintervention status was markedly improved after the eculizumab treatment. Of 13 patients who did not continue eculizumab, 6 showed insufficiencies. Early onset MG was most effective. However, 15 patients switching from eculizumab to ravulizumab kept favorable response and tolerability. Questionnaire surveys showed preference for ravulizumab over eculizumab. INTERPRETATION: Eculizumab and switching to ravulizumab showed to be effective for refractory AChR+ gMG patients in clinical settings.

Therapeutic Responses to Efgartigimod for Generalized Myasthenia Gravis in Japan.

Background and Objectives: Efgartigimod, which has been well tolerated and efficacious in individuals with generalized myasthenia gravis (MG), is available in Japan not only for the treatment of anti-acetylcholine receptor-positive (AChR+) but also anti-muscle-specific receptor tyrosine kinase (MuSK+) and seronegative generalized MG. We report details of the use of efgartigimod for generalized MG in clinical practice in Japan. Methods: We included patients with generalized MG in the 2021 survey of Japan Myasthenia Gravis Registry (JAMG-R) study group who received an initial cycle of efgartigimod between May and September 2022. We defined "responders" as patients who achieved a score ≥2 points for MG activities of daily living (MG-ADL) in the first treatment cycle. The MG composite and the Revised scale of the 15-item Myasthenia Gravis-Quality of Life scale (MG-QOL15-r) were also evaluated. Results: Of 1,343 JAMG-R patients, 36 (2.7%) started efgartigimod (female 68%, age 53 years). Their serologic profiles were as follows: AChR+, n = 19 (53%); MuSK+, n = 6 (17%); and seronegative, n = 11 (31%). Twenty-six patients (72%) had refractory MG. There were 81 cycles of efgartigimod during the 26-week observation in 34 patients (average, 2.4 cycles). The mean interval between cycles was 5.9 weeks. A continuous 4-weekly infusion of efgartigimod was performed in 65 (80%) of 81 cycles. In the first cycle, the MG-ADL score of the 34 patients decreased significantly from 10.5 ± 4.3 to 6.9 ± 5.1 (p = 0.003). Similarly, the mean MG composite and MG-QOL15-r decreased from 18.4 ± 13.6 to 11.8 ± 9.6 (p = 0.004) and from 19.2 ± 6.3 to 14.2 ± 8.3 (p = 0.007), respectively. Twenty-one (62%) patients were responders. Therapeutic responses were observed in the subsequent cycles. The duration of effectiveness of efgartigimod was varied among the responders; 4 responders had only a single effective cycle. Significant improvement was observed in the MuSK+ patients. Prednisolone dose of 7 patients was reduced. Our examination of the patients' postintervention status revealed that 6 patients achieved minimal manifestations. COVID-19 occurred in 5 patients. We failed to detect clinical or laboratory findings associated with responders. Discussion: Efgartigimod can be considered for the treatment of patients with generalized MG who do not achieve minimal manifestations, with a broad flexibility of patient selection and treatment schedules.

Facioscapulohumeral muscular dystrophy Health Index: Japanese translation and validation study.

PURPOSE: The Facioscapulohumeral Muscular Dystrophy Health Index (FSHD-HI) is a patient-reported outcome measure developed for patients with FSHD. This study aimed to translate the FSHD-HI into Japanese (FSHD-HI-J), evaluate cultural adaptation, and examine its psychometric properties. MATERIALS AND METHODS: We created two forward translations, integrated them into a single Japanese version, and evaluated the back-translated version of the FSHD-HI. After finalizing the translation and cultural adaptation, we conducted a survey of 66 patients with FSHD to examine the reliability and validity of the FSHD-HI-J. For psychometric evaluations, we used Cronbach's alpha to assess internal consistency, the intraclass correlation coefficient (ICC) for test-retest reliability, and assessed validity based on the associations between FSHD-HI-J, clinical variables, and quality of life measures. RESULTS: The FSHD-HI-J was found to be clinically relevant, indicating high internal consistency and test-retest reliability (ICC = 0.92 [95% confidence interval: 0.86-0.95] for the total score), as well as significant associations with clinical variables (D4Z4 repeats and functional impairment) and other quality of life measures (|rho| = 0.25-0.73). CONCLUSIONS: The FSHD-HI-J is a valid and reliable patient-reported outcome measure for Japanese patients with FSHD. This validated, disease-specific patient-reported outcome is essential for future clinical practice and clinical trials.

Facioscapulohumeral muscular dystrophy (FSHD) affects not only a patient's physical abilities but also their social activities, participation, and overall quality of life.The FSHD-Health Index (FSHD-HI) is an instrument developed as a disease-specific patient-reported outcome measure to evaluate the burden experienced by patients.The Japanese version of the FSHD-HI has been established as a reliable and validated measure for Japanese-speaking patients with FSHD.The Japanese version of the FSHD-HI can serve as a useful instrument for evaluating the effectiveness of interventions in future trials.

Erythromycin for myotonic dystrophy type 1: a multicentre, randomised, double-blind, placebo-controlled, phase 2 trial.

Background: Myotonic dystrophy type 1 (DM1) is a devastating multisystemic disorder caused by a CTG repeat expansion in the DMPK gene, which subsequently triggers toxic RNA expression and dysregulated splicing. In a preclinical study, we demonstrated that erythromycin reduces the toxicity of abnormal RNA and ameliorates the aberrant splicing and motor phenotype in DM1 model mice. Methods: This multicentre, randomised, double-blind, placebo-controlled, phase 2 trial was conducted at three centres in Japan to translate preclinical findings into practical applications in patients with DM1 by evaluating the safety and efficacy of erythromycin. Between Nov 29, 2019, and Jan 20, 2022, a total of 30 adult patients with DM1 were enrolled and randomly assigned in a 1:2:2 ratio to receive either placebo or erythromycin at two daily doses (500 mg or 800 mg) for 24 weeks. The primary outcome included the safety and tolerability of erythromycin. The secondary efficacy measures included splicing biomarkers, 6-min walk test results, muscle strength, and serum creatinine kinase (CK) values. This trial is registered with the Japan Registry of Clinical Trials, jRCT2051190069. Findings: Treatment-related gastrointestinal symptoms occurred more frequently in the erythromycin group, but all adverse events were mild to moderate and resolved spontaneously. No serious safety concerns were identified. The CK levels from baseline to week 24 decreased in the overall erythromycin group compared with the placebo group (mean change of -6.4 U/L [SD 149] vs +182.8 [SD 228]), although this difference was not statistically significant (p = 0.070). Statistically significant improvements in the overall erythromycin treated groups compared to placebo were seen for two of the eleven splicing biomarkers that were each evaluated in half of the trial sample. These were MBNL1 (p = 0.048) and CACNA1S (p = 0.042). Interpretation: Erythromycin demonstrated favourable safety and tolerability profiles in patients with DM1. A well-powered phase 3 trial is needed to evaluate efficacy, building on the preliminary findings from this study. Funding: Japan Agency for Medical Research and Development.

RGMa collapses the neuronal actin barrier against disease-implicated protein and exacerbates ALS.

Repulsive guidance molecule A (RGMa) was originally identified as a neuronal growth cone-collapsing factor. Previous reports have demonstrated the multifunctional roles of RGMa mediated by neogenin1. However, the pathogenic involvement of RGMa in amyotrophic lateral sclerosis (ALS) remains unclear. Here, we demonstrated that RGMa concentration was elevated in the cerebrospinal fluid of both patients with ALS and transgenic mice overexpressing the mutant human superoxide dismutase1 (mSOD1 mice). Treatment with humanized anti-RGMa monoclonal antibody ameliorated the clinical symptoms in mSOD1 mice. Histochemical analysis revealed that the anti-RGMa antibody significantly decreased mutant SOD1 protein accumulation in the motor neurons of mSOD1 mice via inhibition of actin depolymerization. In vitro analysis revealed that the anti-RGMa antibody inhibited the cellular uptake of the mutant SOD1 protein, presumably by reinforcing the neuronal actin barrier. Collectively, these data suggest that RGMa leads to the collapse of the neuronal actin barrier and promotes aberrant protein deposition, resulting in exacerbation of the ALS pathology.

Enhancing evidence-informed policymaking in medicine and healthcare: stakeholder involvement in the Commons Project for rare diseases in Japan.

BACKGROUND: Although stakeholder involvement in policymaking is attracting attention in the fields of medicine and healthcare, a practical methodology has not yet been established. Rare-disease policy, specifically research priority setting for the allocation of limited research resources, is an area where evidence generation through stakeholder involvement is expected to be effective. We generated evidence for rare-disease policymaking through stakeholder involvement and explored effective collaboration among stakeholders. METHODS: We constructed a space called 'Evidence-generating Commons', where patients, family members, researchers, and former policymakers can share their knowledge and experiences and engage in continual deliberations on evidence generation. Ten rare diseases were consequently represented. In the 'Commons', 25 consecutive workshops were held predominantly online, from 2019 to 2021. These workshops focused on (1) clarification of difficulties faced by rare-disease patients, (2) development and selection of criteria for priority setting, and (3) priority setting through the application of the criteria. For the first step, an on-site workshop using sticky notes was held. The data were analysed based on KJ method. For the second and third steps, workshops on specific themes were held to build consensus. The workshop agendas and methods were modified based on participants' feedback. RESULTS: The 'Commons' was established with 43 participants, resulting in positive effects such as capacity building, opportunities for interactions, mutual understanding, and empathy among the participants. The difficulties faced by patients with rare diseases were classified into 10 categories. Seven research topics were identified as priority issues to be addressed including 'impediments to daily life', 'financial burden', 'anxiety', and 'burden of hospital visits'. This was performed by synthesising the results of the application of the two criteria that were particularly important to strengthen future research on rare diseases. We also clarified high-priority research topics by using criteria valued more by patients and family members than by researchers and former policymakers, and criteria with specific perspectives. CONCLUSION: We generated evidence for policymaking in the field of rare diseases. This study's insights into stakeholder involvement can enhance evidence-informed policymaking. We engaged in comprehensive discussions with policymakers regarding policy implementation and planned analysis of the participants' experiences in this project.

Stakeholder involvement is significant for effective policymaking in the field of rare diseases. However, practical methods for this involvement have not yet been established. Therefore, we developed the 'Commons project' to generate valuable policymaking information and explore effective ways for stakeholders' collaboration. This article explains the process and results of 25 continuous workshops, held from 2019 to 2021 with 43 participants, including patients, family members, researchers, and former policymakers. The main achievements of the discussion that took place in the 'Commons' included a presentation of the overview of the difficulties faced by patients with rare diseases and formulation of high priority research topics.First, the difficulties faced by patients with rare diseases were grouped into 10 categories. Second, seven research topics were identified as priority issues including 'impediments to daily life', 'financial burden', 'anxiety', and 'burden of hospital visits'. During the project process, positive effects such as capacity building, opportunities for interactions, mutual understanding, and empathy among the participants, were identified. Beyond the context of the field of rare diseases and science of policy, these findings are useful for the future of society, including co-creation among stakeholders and patient and public involvement. Based on this study's results, we have initiated communications with policy stakeholders in the field of rare diseases, with the aim of policy implementation.

Clinical features and outcomes of patients with muscle-specific kinase antibody-positive myasthenia gravis in Japan.

This study included 51 patients with muscle-specific kinase antibody-positive myasthenia gravis (MuSK-MG) from a Japanese multicenter survey to examine clinical features and outcomes. Median onset age was 37 years and female predominance was observed. All patients developed generalized symptoms and almost all (50/51) patients had bulbar symptoms. About half of the patients met the criteria for refractory MG. The refractory group had a lower age of onset, higher severity scores, and higher maximum daily doses of oral prednisolone compared to the nonrefractory group. The outcomes for MuSK-MG patients in Japan are not favorable, indicating the need for more aggressive treatment.

Efficacy confirmation study of aceneuramic acid administration for GNE myopathy in Japan.

BACKGROUND: A rare muscle disease, GNE myopathy is caused by mutations in the GNE gene involved in sialic acid biosynthesis. Our recent phase II/III study has indicated that oral administration of aceneuramic acid to patients slows disease progression. METHODS: We conducted a phase III, randomized, placebo-controlled, double-blind, parallel-group, multicenter study. Participants were assigned to receive an extended-release formulation of aceneuramic acid (SA-ER) or placebo. Changes in muscle strength and function over 48 weeks were compared between treatment groups using change in the upper extremity composite (UEC) score from baseline to Week 48 as the primary endpoint and the investigator-assessed efficacy rate as the key secondary endpoint. For safety, adverse events, vital signs, body weight, electrocardiogram, and clinical laboratory results were monitored. RESULTS: A total of 14 patients were enrolled and given SA-ER (n = 10) or placebo (n = 4) tablets orally. Decrease in least square mean (LSM) change in UEC score at Week 48 with SA-ER (- 0.115 kg) was numerically smaller as compared with placebo (- 2.625 kg), with LSM difference (95% confidence interval) of 2.510 (- 1.720 to 6.740) kg. In addition, efficacy was higher with SA-ER as compared with placebo. No clinically significant adverse events or other safety concerns were observed. CONCLUSIONS: The present study reproducibly showed a trend towards slowing of loss of muscle strength and function with orally administered SA-ER, indicating supplementation with sialic acid might be a promising replacement therapy for GNE myopathy. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov (NCT04671472).

Longitudinal Changes in Neuropsychological Functioning in Japanese Patients with Myotonic Dystrophy Type 1: A Five Year Follow-Up Study.

BACKGROUND: Myotonic dystrophy type 1 (DM1) is a form of muscular dystrophy that causes various symptoms, including those of the central nervous system. Some studies have reported cognitive decline in patients with DM1, although the available evidence is limited. OBJECTIVE: This study aimed to describe longitudinal differences in neuropsychological function in patients with DM1. METHODS: A total of 66 Japanese adult patients with DM1 were investigated using a neuropsychological battery to assess several cognitive domains, including memory, processing speed, and executive function. The patients underwent neuropsychological evaluation approximately five years after baseline (Times 1 and 2). RESULTS: Thirty-eight patients underwent a second neuropsychological evaluation. The participants in the Time 2 evaluation were younger than those who did not participate in Time 2. Patients showed a decline in the Mini-Mental State Examination, Trail Making Test (TMT), Block Design, and Symbol Digit Modalities Test at Time 2 (P < 0.05). Age at Time 1 was associated with a decline in TMT-A and TMT-B scores (rho = 0.57 and 0.45, respectively). CONCLUSION: These results suggest a cognitive decline in patients with DM1 and warrant further investigation into the possible effects of age-related changes.

Optical measurement of gating pore currents in hypokalemic periodic paralysis model cells.

Hypokalemic periodic paralysis (HypoPP) is a rare genetic disease associated with mutations in CACNA1S or SCN4A encoding the voltage-gated Ca2+ channel Cav1.1 or the voltage-gated Na+ channel Nav1.4, respectively. Most HypoPP-associated missense changes occur at the arginine residues within the voltage-sensing domain (VSD) of these channels. It is established that such mutations destroy the hydrophobic seal that separates external fluid and the internal cytosolic crevices, resulting in the generation of aberrant leak currents called gating pore currents. Presently, the gating pore currents are thought to underlie HypoPP. Here, based on HEK293T cells and by using the Sleeping Beauty transposon system, we generated HypoPP-model cell lines that co-express the mouse inward-rectifier K+ channel (mKir2.1) and HypoPP2-associated Nav1.4 channel. Whole-cell patch-clamp measurements confirmed that mKir2.1 successfully hyperpolarizes the membrane potential to levels comparable to those of myofibers, and that some Nav1.4 variants induce notable proton-based gating pore currents. Importantly, we succeeded in fluorometrically measuring the gating pore currents in these variants by using a ratiometric pH indicator. Our optical method provides a potential in vitro platform for high-throughput drug screening, not only for HypoPP but also for other channelopathies caused by VSD mutations.

Phase II/III Study of Aceneuramic Acid Administration for GNE Myopathy in Japan.

BACKGROUND: GNE myopathy is an ultra-rare muscle disease characterized by a reduction in the synthesis of sialic acid derived from pathogenic variants in the GNE gene. No treatment has been established so far. OBJECTIVE: We evaluated the safety and efficacy of oral supplementation of aceneuramic acid in patients with GNE myopathy. METHODS: This multicenter, placebo-controlled, double-blind study comprised genetically confirmed GNE myopathy patients in Japan who were randomly assigned into treatment groups of sialic acid-extended release (SA-ER) tablets (6 g/day for 48 weeks) or placebo groups (4:1). The primary endpoint of effectiveness was set as the change in total upper limb muscle strength (upper extremity composite [UEC] score) from the start of administration to the final evaluation time point. RESULTS: Among the 20 enrolled patients (SA-ER group, 16; placebo group, 4), 19 completed this 48-week study. The mean value of change in UEC score (95% confidence interval [CI]) at 48 weeks was -0.1 kg (-2.1 to 2.0) in the SA-ER group and -5.1 kg (-10.4 to 0.3) in the placebo group. The least squares mean difference (95% CI) between the groups in the covariance analysis was 4.8 kg (-0.3 to 9.9; P = 0.0635). The change in UEC score at 48 weeks was significantly higher in the SA-ER group compared with the placebo group (P = 0.0013) in the generalized estimating equation test repeated measurement analysis. In one patient in the SA-ER group, who was found to be pregnant 2 weeks after drug administration fetal death with tangled umbilical cord occurred at 13 weeks after the discontinuation of treatment. No other serious adverse effects were observed. CONCLUSIONS: The present study indicates that oral administration of SA-ER tablets is effective and safe in patients with GNE myopathy in Japan.