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Accessible Summary What Is Known on the Subject What the Paper Adds to Existing Knowledge What Are the Implications for Practice Introduction Methods Findings Discussion Conclusion Following their experience, patients with physical restraints often experienced traumatic sensations. The experiences of healthcare professionals' (HCPs') are primarily concerned with moral distress or conflicts between loyalty to the treatment and oppression of the patient's freedom when implementing RIs. Improving the competency of HCPs can help establish therapeutic relationships rooted in compassionate care and facilitate appropriate assessments to determine whether and how often RIs are necessary. Furthermore, fostering an environment that guarantees patient safety and dignity, assuring a sufficient staffing ratio, and providing opportunities to share RI experiences can help improve the quality of care and build safe environments for RIs. Effective interaction between HCPs and patients, thorough patient assessment, and compassionate patient care may improve competency of HCPs intervene RIs procedures. Creating a safe therapeutic environment, including improvements to structural environments, increasing the staff‐to‐patient ratio, establishing organizational policies that guarantee staff debriefing, provide emotional support, provide appropriate training programs to HCPs to their coping skills during RIs also reduce the use of RIs and improve the quality of mental health care. Restrictive interventions (RIs) are used in psychiatric inpatient units for ensuring safety. However, few studies have comprehensively reviewed physical restraint and seclusion experiences from the perspectives of both patients and healthcare professionals' (HCPs'). This study aims to gain an in‐depth understanding of the RI experiences of mental health inpatients and HCPs.A meta‐synthesis was undertaken of qualitative studies exploring the RI experiences. Five electronic databases were searched and additional manual searches were performed for studies published within the last decade. Twelve articles were included, and a thematic analysis was conducted. The Critical Appraisal Skills Program (CASP) checklist was used to assess data quality.Two main subthemes were identified: ‘Competency of HCPs’ (three subthemes: interaction between patients and HCPs, assessment methods, and care) and ‘systems’ (three subthemes: environment, protocols with training, and debriefing), including both positive and negative experiences.The Competency of HCPs and the ward environment are critical factors related to patients' unmet needs. Effective interactions between HCPs and patients, thorough patient assessments, and compassionate patient care are important elements of RI implementation.An environment that guarantees safety and care with dignity, sufficient staffing ratios, and opportunities to share RI experiences may improve quality of care and create safe environments for RIs. [ABSTRACT FROM AUTHOR]

Mutations in the SACS gene are associated with autosomal recessive spastic ataxia of Charlevoix-Saguenay disease (ARSACS) or complex clinical phenotypes of Charcot-Marie-Tooth disease (CMT). This study aimed to identify SACS mutations in a Korean CMT cohort with cerebellar ataxia and spasticity by whole exome sequencing (WES). As a result, eight pathogenic SACS mutations in four families were identified as the underlying causes of these complex phenotypes. The prevalence of CMT families with SACS mutations was determined to be 0.3%. All the patients showed sensory, motor, and gait disturbances with increased deep tendon reflexes. Lower limb magnetic resonance imaging (MRI) was performed in four patients and all had fatty replacements. Of note, they all had similar fatty infiltrations between the proximal and distal lower limb muscles, different from the neuromuscular imaging feature in most CMT patients without SACS mutations who had distal dominant fatty involvement. Therefore, these findings were considered a characteristic feature in CMT patients with SACS mutations. Although further studies with more cases are needed, our results highlight lower extremity MRI findings in CMT patients with SACS mutations and broaden the clinical spectrum. We suggest screening for SACS in recessive CMT patients with complex phenotypes of ataxia and spasticity. [ABSTRACT FROM AUTHOR]

Mutations in the Microrchidia CW-type zinc finger 2 (MORC2) GHKL ATPase module cause a broad range of neuropathies, such as Charcot-Marie-Tooth disease type 2Z; however, the aetiology and therapeutic strategy are not fully understood. Previously, we reported that the Morc2a p.S87L mouse model exhibited neuropathy and muscular dysfunction through DNA damage accumulation. In the present study, we analysed the gene expression of Morc2a p.S87L mice and designated the primary causing factor. We investigated the pathological pathway using Morc2a p.S87L mouse embryonic fibroblasts and human fibroblasts harbouring MORC2 p.R252W. We subsequently assessed the therapeutic effect of gene therapy administered to Morc2a p.S87L mice. This study revealed that Morc2a p.S87L causes a protein synthesis defect, resulting in the loss of function of Morc2a and high cellular apoptosis induced by high hydroxyl radical levels. We considered the Morc2a GHKL ATPase domain as a therapeutic target because it simultaneously complements hydroxyl radical scavenging and ATPase activity. We used the adeno-associated virus (AAV)-PHP.eB serotype, which has a high CNS transduction efficiency, to express Morc2a or Morc2a GHKL ATPase domain protein in vivo. Notably, AAV gene therapy ameliorated neuropathy and muscular dysfunction with a single treatment. Loss-of-function characteristics due to protein synthesis defects in Morc2a p.S87L were also noted in human MORC2 p.S87L or p.R252W variants, indicating the correlation between mouse and human pathogenesis. In summary, CMT2Z is known as an incurable genetic disorder, but the present study demonstrated its mechanisms and treatments based on established animal models. This study demonstrates that the Morc2a p.S87L variant causes hydroxyl radical-mediated neuropathy, which can be rescued through AAV-based gene therapy. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the psychometric properties of the Korean version of the perceived costs and benefits scale (K-PCBS) for sexual intercourse to deepen our understanding of the complex psychosocial and interpersonal elements influencing young people's sexual decision-making. The study participants were 227 college students in South Korea aged 18–25 years. Two factors were extracted through factor analysis, accounting for 61.05% and 58.18% of the variance for perceived costs and perceived benefits, respectively, and showed a good model fit in the K-PCBS. Reliability was high, as indicated by Cronbach's alphas of 0.87 and 0.84 for the perceived costs and perceived benefits subscales, respectively. The results indicate that the K-PCBS may serve as an appropriate instrument for measuring South Korean youth's cost and benefit analysis regarding their sexual decision-making. Our study makes a significant contribution to the literature and field because it identifies the underlying feelings and attitudes of young adults toward engaging in sexual activities using the K-PCBS for sexual intercourse, which has good reliability, validity, and internal consistency. [ABSTRACT FROM AUTHOR]

Background and purpose: Elevated plasma concentrations of neural cell adhesion molecule 1 (NCAM1) and p75 neurotrophin receptor (p75) in patients with peripheral neuropathy have been reported. This study aimed to determine the specificity of plasma concentration elevation of either NCAM1 or p75 in a subtype of Charcot–Marie–Tooth disease (CMT) and its correlation with pathologic nerve status and disease severity. Methods: Blood samples were collected from 138 patients with inherited peripheral neuropathy and 51 healthy controls. Disease severity was measured using Charcot–Marie–Tooth Neuropathy Score version 2 (CMTNSv2), and plasma concentrations of NCAM1 and p75 were analyzed by enzyme‐linked immunosorbent assay. Eight sural nerves from CMT patients were examined to determine the relation of histopathology and plasma NCAM1 levels. Results: Plasma concentration of NCAM1, but not p75, was specifically increased in demyelinating subtypes of CMT (median = 7100 pg/mL, p < 0.001), including CMT1A, but not in axonal subtype (5964 pg/mL, p > 0.05), compared to the control (3859 pg/mL). CMT1A patients with mild or moderate severity (CMTNSv2 < 20) showed higher levels of plasma NCAM1 than healthy controls. Immunofluorescent NCAM1 staining for the sural nerves of CMT patients showed that NCAM1‐positive onion bulb cells and possible demyelinating Schwann cells might be associated with the specific increase of plasma NCAM1 in demyelinating CMT. Conclusions: The plasma NCAM1 levels in demyelinating CMT might be a surrogate biomarker reflecting pathological Schwann cell status and disease progression. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to investigate the serial mediating effects of the time mothers spend with their adolescent children and the adolescents' self-esteem on the relationship between mothers' and adolescents' problematic smartphone use. Patients and Methods: This study was a secondary analysis of data extracted from the Korean Children and Youth Panel Survey (KCYPS) in 2018, which comprised data on first-year middle school students. Mediation analysis was conducted using Model 6 of the Hayes' PROCESS macro for SPSS. Results: The mediating effect of the time mothers spent with adolescents on the relationship between mothers' and adolescents' problematic smartphone use was significant, but the mediating effect of adolescents' self-esteem was not significant. Mothers' problematic smartphone use was found to significantly affect adolescents' problematic smartphone use by sequentially mediating the time mothers spent with adolescent children and adolescents' self-esteem. Conclusion: It was concluded that, to lower adolescents' problematic smartphone use due to mothers' problematic smartphone use, appropriate interventions should be formulated to help adolescents develop higher self-esteem through sufficient mother–child interaction time. [ABSTRACT FROM AUTHOR]

Charcot–Marie–Tooth disease (CMT) is a group of inherited peripheral nerve disorders characterized by progressive muscle weakness and atrophy, sensory loss, foot deformities and steppage gait. Missense mutations in the gene encoding the small heat shock protein HSPB8 (HSP22) have been associated with hereditary neuropathies, including CMT. HSPB8 is a member of the small heat shock protein family sharing a highly conserved α-crystallin domain that is critical to its chaperone activity. In this study, we modeled HSPB8 mutant-induced neuropathies in Drosophila. The overexpression of human HSPB8 mutants in Drosophila neurons produced no significant defect in fly development but led to a partial reduction in fly lifespan. Although these HSPB8 mutant genes failed to induce sensory abnormalities, they reduced the motor activity of flies and the mitochondrial functions in fly neuronal tissue. The motor defects and mitochondrial dysfunction were successfully restored by PINK1 and parkin, which are Parkinson's disease-associated genes that have critical roles in maintaining mitochondrial function and integrity. Consistently, kinetin riboside, a small molecule amplifying PINK1 activity, also rescued the loss of motor activity in our HSPB8 mutant model. [ABSTRACT FROM AUTHOR]

Mutations in INF2 are associated with the complex symptoms of Charcot‐Marie‐Tooth disease (CMT) and focal segmental glomerulosclerosis (FSGS). To date, more than 100 and 30 genes have been reported to cause these disorders, respectively. This study aimed to identify INF2 mutations in Korean patients with CMT. This study was conducted with 743 Korean families with CMT who were negative for PMP22 duplication. In addition, a family with FSGS was included in this study. INF2 mutations were screened using whole exome sequencing (WES) and filtering processes. As the results, four pathogenic INF2 mutations were identified in families with different clinical phenotypes: p.L78P and p.L132P in families with symptoms of both CMT and FSGS; p.C104Y in a family with CMT; and p.R218Q in a family with FSGS. Moreover, different CMT types were observed in families with CMT symptoms: CMT1 in two families and Int‐CMT in another family. Hearing loss was observed in two families with CMT1. Pathogenicity was predicted by in silico analyses, and considerable conformational changes were predicted in the mutant proteins. Two mutations (p.L78P and p.C104Y) were unreported, and three families showed de novo mutations that were putatively occurred from fathers. This study suggests that patients with INF2 mutations show a broad phenotypic spectrum: CMT1, CMT1 + FSGS, CMTDIE + FSGS, and FSGS. Therefore, the genotype‐phenotype correlation may be more complex than previously recognized. We believe that this study expands the clinical spectrum of patients with INF2 mutations and will be helpful in the molecular diagnosis of CMT and FSGS. [ABSTRACT FROM AUTHOR]

This study aimed to explore the effects of meaning-in-life intervention on meaning in life, quality of life, spiritual well-being, anxiety, and depression in advanced cancer patients. Databases, including Ovid Medline, Cochrane, PsycINFO, CINAHL, and Embase, were searched to identify relevant randomized controlled trials based on predefined criteria. Seven studies were included. Meta-analysis was performed for five studies, involving 718 patients with advanced cancer. The meta-analysis revealed no significant effects of the meaning-in-life intervention on spiritual well-being, depression, and anxiety of advanced cancer patients. The insufficient number of studies and risk of bias limit the strength of the conclusions. Therefore, further studies with larger sample sizes and methodologically rigorous designs are required to evaluate the effects of meaning-in-life interventions for advanced cancer patients. Our findings can support a better understanding of the need to study meaning-in-life interventions in advanced cancer patients and foster sustained attention to recognize meaning-in-life interventions as an effective method in healthcare. [ABSTRACT FROM AUTHOR]

Small heat shock proteins (sHSPs) are ATP-independent chaperones that help correct the folding of denatured proteins and protect cells from stress. Mutations in HSPB1, HSPB8, and HSPB3 are implicated in inherited peripheral neuropathies (IPNs), such as Charcot-Marie-Tooth disease type 2 (CMT2) and distal hereditary motor neuropathies (dHMN). This study, using whole exome sequencing or targeted gene sequencing, identified 9 pathogenic or likely pathogenic variants in these three sHSP genes from 11 Korean IPN families. Most variants were located in the evolutionally well conserved α-crystallin domain, except for p.P182S and p.S187L in HSPB1. As an atypical case, a patient with dHMN2 showed two compound heterozygous variants of p.R127Q and p.Y142H in HSPB1, suggesting a putative case of recessive inheritance, which requires additional research to confirm. Three HSPB8 variants were located in the p.K141 residue, which seemed to be a mutational hot spot. There were no significant differences between patient groups, which divided by sHSP genes for clinical symptoms such as onset age, severity, and nerve conduction. Early-onset patients showed a tendency of slightly decreased sensory nerve conduction values compared with late-onset patients. As a first Korean IPN cohort study examining sHSP genes, these results will, we believe, be helpful for molecular diagnosis and care of patients with CMT2 and dHMN. [ABSTRACT FROM AUTHOR]

Charcot‐Marie‐Tooth disease (CMT) and related diseases are a genetically and clinically heterogeneous group of peripheral neuropathies. Particularly, mutations in several aminoacyl‐tRNA synthetase (ARS) genes have been reported to cause axonal CMT (CMT2) or distal hereditary motor neuropathy (dHMN). However, the common pathogenesis among CMT subtypes by different ARS gene defects is not well understood. This study was performed to investigate ARS gene mutations in a CMT cohort of 710 Korean families. Whole‐exome sequencing was applied to 710 CMT patients who were negative for PMP22 duplication. We identified 12 disease‐causing variants (from 13 families) in GARS1, AARS1, HARS1, WARS1, and YARS1 genes. Seven variants were determined to be novel. The frequency of overall ARS gene mutations was 1.22% among all independent patients diagnosed with CMT and 1.83% in patients negative for PMP22 duplication. WARS1 mutations have been reported to cause dHMN; however, in our patients with WARS1 variants, CMT was associated with sensory involvement. We analyzed genotype‐phenotype correlations and expanded the phenotypic spectrum of patients with CMT possessing ARS gene variants. We also characterized clinical phenotypes according to ARS genes. This study will be useful for performing exact molecular and clinical diagnoses and providing reference data for other population studies. [ABSTRACT FROM AUTHOR]

Charcot‐Marie‐Tooth disease type 2D (CMT2D), is a hereditary peripheral neuropathy caused by mutations in the gene encoding glycyl‐tRNA synthetase (GARS1). Here, human induced pluripotent stem cell (hiPSC)‐based models of CMT2D bearing mutations in GARS1 and their use for the identification of predictive biomarkers amenable to therapeutic efficacy screening is described. Cultures containing spinal cord motor neurons generated from this line exhibit network activity marked by significant deficiencies in spontaneous action potential firing and burst fire behavior. This result matches clinical data collected from a patient bearing a GARS1P724H mutation and is coupled with significant decreases in acetylated α‐tubulin levels and mitochondrial movement within axons. Treatment with histone deacetylase 6 inhibitors, tubastatin A and CKD504, improves mitochondrial movement and α‐tubulin acetylation in these cells. Furthermore, CKD504 treatment enhances population‐level electrophysiological activity, highlighting its potential as an effective treatment for CMT2D. [ABSTRACT FROM AUTHOR]

Charcot–Marie–Tooth disease (CMT) is the most common hereditary peripheral neuropathy. Mutations in the neurofilament light polypeptide (NEFL) gene produce diverse clinical phenotypes, including demyelinating (CMT1F), axonal (CMT2E), and intermediate (CMTDIG) neuropathies. From 2005 to 2020, 1,143 Korean CMT families underwent gene sequencing, and we investigated the clinical, genetic, and neuroimaging spectra of NEFL‐related CMT patients. Ten NEFL mutations in 17 families (1.49%) were identified, of which three (p.L312P, p.Y443N, and p.K467N) were novel. Eight de novo cases were identified at a rate of 0.47 based on a cosegregation analysis. The age of onset was ≤3 years in five cases (13.5%). The patients revealed additional features including delayed walking, ataxia, dysphagia, dysarthria, dementia, ptosis, waddling gait, tremor, hearing loss, and abnormal visual evoked potential. Signs of ataxia were found in 26 patients (70.3%). In leg MRI analyses, various degrees of intramuscular fat infiltration were found. All compartments were evenly affected in CMT1F patients. The anterior and anterolateral compartments were affected in CMT2E, and the posterior compartment was affected in CMTDIG. Thus, NEFL‐related CMT patients showed phenotypic heterogeneities. This study's clinical, genetic, and neuroimaging results could be helpful in the evaluation of novel NEFL variants and differential diagnosis against other CMT subtypes. [ABSTRACT FROM AUTHOR]

Background: Charcot‐Marie‐Tooth disease (CMT) is the most common disorder of inherited peripheral neuropathies characterized by distal muscle weakness and sensory loss. CMT is usually classified into three types, demyelinating, axonal, and intermediate neuropathies. Mutations in myelin protein zero (MPZ) gene which encodes a transmembrane protein of the Schwann cells as a major component of peripheral myelin have been reported to cause various type of CMT. Methods: This study screened MPZ mutations in Korean CMT patients (1,121 families) by whole exome sequencing and targeted sequencing. Results: We identified 22 pathogenic or likely pathogenic MPZ mutations in 36 families as the underlying cause of the CMT1B, CMTDID, or CMT2I subtypes. Among them, five mutations were novel. The frequency of CMT patients with the MPZ mutations was similar or slightly lower compared to other ethnic groups. Conclusions: We showed that the median onset ages and clinical phenotypes varied by subtypes: the most severe in the CMT1B group, and the mildest in the CMT2I group. This study also observed a clear correlation that earlier onsets cause more severe symptoms. We believe that this study will provide useful reference data for genetic and clinical information on CMT patients with MPZ mutations in Korea. [ABSTRACT FROM AUTHOR]

Background and Purpose: Charcot-Marie-Tooth (CMT) disease is the most common hereditary peripheral neuropathy. CMT type 1A (CMT1A) accounts for approximately 50% of CMT patients and is linked to PMP22 gene duplication. Histone deacetylase-6 (HDAC6) has pleiotropic effects, such as regulating lipid homeostasis and cellular stress. Although HDAC6 has been regarded as a promising drug target for neurodegenerative diseases, its inhibition has not yet been tested in CMT1A. Here we have tested the therapeutic potential of CKD-504, a clinical stage HDAC6 inhibitor, in a mouse model of CMT1A EXPERIMENTAL APPROACH: The potency and selectivity of CKD-504 was evaluated, using a HDAC enzyme panel assay and western blots. The therapeutic potential of CKD-504 was evaluated using behavioural testing and electrophysiological assessments in the C22 mouse model of CMT1A. PMP22 protein expression and aggregation were analysed in mesenchymal stem cell-derived Schwann cells from CMT1A patients and sciatic nerves from C22 mice.Key Results: The HDAC6 inhibitor, CKD-504, modulated molecular chaperon proteins such as HSP90 and HSP70, which are involved in the folding/refolding of proteins such as PMP22. CKD-504 treatment restored myelination in both mesenchymal stem cell-derived Schwann cells from CMT1A patients and sciatic nerves of C22 mice and improved the axonal integrity of the sciatic nerve, leading to behavioural, electrophysiological, and histological improvements in C22 mice.Conclusion and Implications: A novel HDAC6 inhibitor, CKD-504, has potent therapeutic efficacy for CMT1A. [ABSTRACT FROM AUTHOR]

Objective: Myelinated Schwann cells (SCs) in adult peripheral nerves dedifferentiate into immature cells in demyelinating neuropathies and Wallerian degeneration. This plastic SC change is actively involved in the myelin destruction and clearance as demyelinating SCs (DSCs). In inherited demyelinating neuropathy, pathologically differentiated and dysmyelinated SCs constitute the main nerve pathology. Methods: We investigated whether this SC plastic status in human neuropathic nerves could be determined by patient sera to develop disease‐relevant serum biomarkers. Based on proteomics analysis of the secreted exosomes from immature SCs, we traced p75 neurotrophin receptor (p75) and neural cell adhesion molecule 1 (NCAM) in the sera of patients with peripheral neuropathy. Results: Enzyme‐linked immunosorbent assay (ELISA) revealed that p75 and NCAM were subtype‐specifically expressed in the sera of patients with peripheral neuropathy. In conjunction with these ELISA data, pathological analyses of animal models and human specimens suggested that the presence of DSCs in inflammatory neuropathy and of supernumerary nonmyelinating or dysmyelinating SCs in inherited neuropathy could potentially be distinguished by comparing the expression profiles of p75 and NCAM. Interpretation: This study indicates that the identification of disease‐specific pathological SC stages might be a valuable tool for differential diagnosis of peripheral neuropathies. [ABSTRACT FROM AUTHOR]

Charcot–Marie–Tooth disease type 1A (CMT1A) is caused by 1.5-fold increased dosage of the PMP22 ; however, onset age and severity vary considerably among patients. The exact reason behind these phenotypic heterogeneities has rarely been discovered yet. Because miRNAs are the key regulators of gene expression, we speculated that variants of miRNAs might be the genetic modifiers for CMT1A. This study noticed a common single nucleotide polymorphism (n.86T > C, rs2292832) in the miR-149 which was predicted to target several CMT causing genes including PMP22 . The rs2292832 was located near the 3′ end of the precursor microRNA of the miR-149 . We performed an association study between the rs2292832 polymorphism and clinical phenotypes of CMT1A in subjects consisting of 176 unrelated Korean CMT1A patients and 176 controls. From this study, we observed that rs2292832 was closely associated to the onset age and severity of CMT1A. Particularly, the TC and CC genotypes were significantly associated with late onset and mild symptom. Therefore, we suggest that the rs2292832 variant in the miR-149 is a potential candidate as a genetic modifier which affects the phenotypic heterogeneity of CMT1A. This study may provide the first evidence that polymorphism in the miR gene is associated with the CMT1A phenotype. [ABSTRACT FROM AUTHOR]

Charcot-Marie-Tooth disease (CMT) is a heterogeneous group of peripheral neuropathies with diverse genetic causes. In this study, we identified p.I43N mutation in PMP2 from a family exhibiting autosomal dominant demyelinating CMT neuropathy by whole exome sequencing and characterized the clinical features. The age at onset was the first to second decades and muscle atrophy started in the distal portion of the leg. Predominant fatty replacement in the anterior and lateral compartment was similar to that in CMT1A caused by PMP22 duplication. Sural nerve biopsy showed onion bulbs and degenerating fibers with various myelin abnormalities. The relevance of PMP2 mutation as a genetic cause of dominant CMT1 was assessed using transgenic mouse models. Transgenic mice expressing wild type or mutant (p.I43N) PMP2 exhibited abnormal motor function. Electrophysiological data revealed that both mice had reduced motor nerve conduction velocities (MNCV). Electron microscopy revealed that demyelinating fibers and internodal lengths were shortened in both transgenic mice. These data imply that overexpression of wild type as well as mutant PMP2 also causes the CMT1 phenotype, which has been documented in the PMP22. This report might expand the genetic and clinical features of CMT and a further mechanism study will enhance our understanding of PMP2-associated peripheral neuropathy. [ABSTRACT FROM AUTHOR]

Charcot–Marie–Tooth disease (CMT) is the most common inherited peripheral neuropathy. Mutations in the GNB4 gene cause dominant intermediate CMT type F (CMTDIF). The aim of this study is to investigate phenotypic heterogeneities and characteristics of CMT patients with GNB4 mutations. We enrolled 1143 Korean CMT families and excluded 344 families with a PMP22 duplication. We further analyzed the 799 remaining families to find their GNB4 mutations using whole-exome sequencing (WES). We identified two mutations (p.Gly77Arg and p.Lys89Glu) in three families, among which a heterozygous p.Gly77Arg mutation was novel. In addition, a significant uncertain variant (p.Thr177Asn) was observed in one family. The frequency of the GNB4 mutation in the Korean population is 0.38% in PMP22 duplication-negative families. All three families showed de novo mutation. Electrophysiological findings regarding the p.Lys89Glu mutation showed that the motor nerve conduction velocity (MNCV) of the median nerve was markedly reduced, indicating demyelinating neuropathy, and sural nerve biopsy revealed severe loss of myelinated axons with onion bulb formation. Lower extremity Magnetic Resonance Imaging (MRI) demonstrated relatively more severe intramuscular fat infiltrations in demyelinating type (p.Lys89Glu mutation) patients compared to intermediate type (p.Gly77Arg mutation) patients. The anterolateral and superficial posterior compartment muscles of the distal calf were preferentially affected in demyelinating type patients. Therefore, it seems that the investigated GNB4 mutations do cause not only the known intermediate type but also demyelinating-type neuropathy. We first presented three Korean families with GNB4 mutations and found phenotypic heterogeneities of both intermediate and demyelinating neuropathy. We suggest that those findings are useful for the differential diagnosis of CMT patients with unknown GNB4 variants. [ABSTRACT FROM AUTHOR]

Distal hereditary motor neuropathies (dHMN) are a group of inherited peripheral nerve disorders characterized by length-dependent motor neuron weakness and subsequent muscle atrophy. Missense mutations in the gene encoding small heat shock protein HSPB1 (HSP27) have been associated with hereditary neuropathies including dHMN. HSPB1 is a member of the small heat shock protein (sHSP) family characterized by a highly conserved α-crystallin domain that is critical to their chaperone activity. In this study, we modeled HSPB1 mutant-induced neuropathies in Drosophila using a human HSPB1S135F mutant that has a missense mutation in its α-crystallin domain. Overexpression of the HSPB1 mutant produced no significant defect in the Drosophila development, however, a partial reduction in the life span was observed. Further, the HSPB1 mutant gene induced an obvious loss of motor activity when expressed in Drosophila neurons. Moreover, suppression of histone deacetylase 6 (HDAC6) expression, which has critical roles in HSPB1 mutant-induced axonal defects, successfully rescued the motor defects in the HSPB1 mutant Drosophila model. • HSPB1 (HSP27) is a member of the small heat shock protein family. • Mutations in HSPB1 cause distal hereditary motor neuropathy and Charcot-Marie-Tooth disease. • The human HSPB1 mutant gene induces loss of motor activity in Drosophila. • HDAC6 inhibition rescues the motor defects in the HSPB1 mutant Drosophila model. [ABSTRACT FROM AUTHOR]