{"title":"Imbalance and lower limb tremor in chronic inflammatory demyelinating polyradiculoneuropathy: Reply to Letter to the Editor","authors":"Matthew Silsby, Steve Vucic","doi":"10.1111/jns.12592","DOIUrl":"10.1111/jns.12592","url":null,"abstract":"","PeriodicalId":17451,"journal":{"name":"Journal of the Peripheral Nervous System","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2023-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10500268","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Asger Bjørnkær, Laura M. Gaist, Jakob V. Holbech, David Gaist, Martin Wirenfeldt, Søren H. Sindrup, Thomas Krøigård
Background and Aims
The diagnosis of small fiber neuropathy (SFN) is supported by reduced intraepidermal nerve fiber density (IENFD). The noninvasive method corneal confocal microscopy (CCM) has the potential to be a practical alternative. We aimed to estimate the diagnostic accuracy of CCM compared with IENFD and cold detection thresholds (CDT) in SFN and mixed fiber neuropathy (MFN).
Methods
CCM was performed in an unselected prospective cohort of patients with a clinical suspicion of polyneuropathy. Predefined criteria were used to classify SFN and MFN. Neuropathy scores, including the Utah early neuropathy scale (UENS), were used to describe severity. Patients with established other diagnoses were used for diagnostic specificity calculations.
Results
Data were taken from 680 patients, of which 244 had SFN or MFN. There was no significant difference in sensitivities [95%CI] of CCM (0.44 [0.38–0.51]), IEFND (0.43 [0.36–0.49]), and CDT (0.34 [0.29–0.41]). CCM specificity (0.75 [0.69–0.81]) was lower (p = .044) than for IENFD (0.99 [0.96–1.00]) but not than for CDT (0.81 [0.75–0.86]). The AUCs of the ROC curves of 0.63, 0.63 and 0.74 respectively, was lower for corneal nerve fiber density (p = .0012) and corneal nerve fiber length (p = .0015) compared with IENFD. While UENS correlated significantly with IENFD (p = .0016; R2 = .041) and CDT (p = .0002; R2 = .056), it did not correlate with CCM measures.
Interpretation
The diagnostic utility of CCM in SNF and MFN is limited by the low specificity compared with skin biopsy. Further, CCM is less suitable than skin biopsy and CDT as a marker for neuropathy severity.
{"title":"Corneal confocal microscopy in small and mixed fiber neuropathy—Comparison with skin biopsy and cold detection in a large prospective cohort","authors":"Asger Bjørnkær, Laura M. Gaist, Jakob V. Holbech, David Gaist, Martin Wirenfeldt, Søren H. Sindrup, Thomas Krøigård","doi":"10.1111/jns.12595","DOIUrl":"10.1111/jns.12595","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background and Aims</h3>\u0000 \u0000 <p>The diagnosis of small fiber neuropathy (SFN) is supported by reduced intraepidermal nerve fiber density (IENFD). The noninvasive method corneal confocal microscopy (CCM) has the potential to be a practical alternative. We aimed to estimate the diagnostic accuracy of CCM compared with IENFD and cold detection thresholds (CDT) in SFN and mixed fiber neuropathy (MFN).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>CCM was performed in an unselected prospective cohort of patients with a clinical suspicion of polyneuropathy. Predefined criteria were used to classify SFN and MFN. Neuropathy scores, including the Utah early neuropathy scale (UENS), were used to describe severity. Patients with established other diagnoses were used for diagnostic specificity calculations.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Data were taken from 680 patients, of which 244 had SFN or MFN. There was no significant difference in sensitivities [95%CI] of CCM (0.44 [0.38–0.51]), IEFND (0.43 [0.36–0.49]), and CDT (0.34 [0.29–0.41]). CCM specificity (0.75 [0.69–0.81]) was lower (<i>p</i> = .044) than for IENFD (0.99 [0.96–1.00]) but not than for CDT (0.81 [0.75–0.86]). The AUCs of the ROC curves of 0.63, 0.63 and 0.74 respectively, was lower for corneal nerve fiber density (<i>p</i> = .0012) and corneal nerve fiber length (<i>p</i> = .0015) compared with IENFD. While UENS correlated significantly with IENFD (<i>p</i> = .0016; <i>R</i><sup>2</sup> = .041) and CDT (<i>p</i> = .0002; <i>R</i><sup>2</sup> = .056), it did not correlate with CCM measures.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Interpretation</h3>\u0000 \u0000 <p>The diagnostic utility of CCM in SNF and MFN is limited by the low specificity compared with skin biopsy. Further, CCM is less suitable than skin biopsy and CDT as a marker for neuropathy severity.</p>\u0000 </section>\u0000 </div>","PeriodicalId":17451,"journal":{"name":"Journal of the Peripheral Nervous System","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2023-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/jns.12595","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10119871","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lu Li, Yongzhi Xie, Sen Zeng, Xiaobo Li, Zhiqiang Lin, Shunxiang Huang, Huadong Zhao, Wanqian Cao, Lei Liu, Jun Liu, Pengfei Rong, Ruxu Zhang
Background and Aims
Biallelic variants in the sorbitol dehydrogenase (SORD) gene have been identified as the genetic cause of autosomal recessive (AR) peripheral neuropathy (PN) manifesting as Charcot–Marie–Tooth disease type 2 (CMT2) or distal hereditary motor neuropathy (dHMN). We aim to observe the genetic and clinical spectrum of a cohort of patients with SORD-related PN (SORD-PN).
Methods
A total of 107 patients with AR or sporadic CMT2/dHMN underwent molecular diagnosis by whole-exome sequencing and subsequent Sanger sequencing validation. Available phenotypic data for SORD-PN were collected and analyzed.
Results
Eleven (10.28%) of 107 patients were identified as SORD-PN, including four with CMT2 and seven with dHMN. The SORD variant c.210 T > G;p.His70Gln in F-d3 was firstly reported and subsequent analysis showed that it resulted in loss of SORD enzyme function. Evidence of subclinical muscle involvement was frequently detected in patients with SORD-PN, including mildly to moderately elevated serum creatine kinase (CK) levels in 10 patients, myogenic electrophysiological changes in one patient, and muscle edema in five patients undergoing lower extremity MRI. Fasting serum sorbitol level was 88-fold higher in SORD-PN patients (9.69 ± 1.07 mg/L) than in healthy heterozygous subjects (0.11 ± 0.01 mg/L) and 138-fold higher than in healthy controls (0.07 ± 0.02 mg/L).
Interpretation
The novel SORD variant c.210 T > G;p.His70Gln and evidence of subclinical muscle involvement were identified, which expanded the genetic and clinical spectrum of SORD-PN. Subclinical muscle involvement might be a common but easily overlooked clinical feature. The serum CK and fasting serum sorbitol levels were expected to be sensitive biomarkers confirmed by follow-up cohort study.
{"title":"Expanding the genetic and clinical spectrum of SORD-related peripheral neuropathy by reporting a novel variant c.210T>G and evidence of subclinical muscle involvement","authors":"Lu Li, Yongzhi Xie, Sen Zeng, Xiaobo Li, Zhiqiang Lin, Shunxiang Huang, Huadong Zhao, Wanqian Cao, Lei Liu, Jun Liu, Pengfei Rong, Ruxu Zhang","doi":"10.1111/jns.12591","DOIUrl":"10.1111/jns.12591","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background and Aims</h3>\u0000 \u0000 <p>Biallelic variants in the sorbitol dehydrogenase (<i>SORD</i>) gene have been identified as the genetic cause of autosomal recessive (AR) peripheral neuropathy (PN) manifesting as Charcot–Marie–Tooth disease type 2 (CMT2) or distal hereditary motor neuropathy (dHMN). We aim to observe the genetic and clinical spectrum of a cohort of patients with SORD-related PN (SORD-PN).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>A total of 107 patients with AR or sporadic CMT2/dHMN underwent molecular diagnosis by whole-exome sequencing and subsequent Sanger sequencing validation. Available phenotypic data for SORD-PN were collected and analyzed.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Eleven (10.28%) of 107 patients were identified as SORD-PN, including four with CMT2 and seven with dHMN. The <i>SORD</i> variant c.210 T > G;p.His70Gln in F-d3 was firstly reported and subsequent analysis showed that it resulted in loss of SORD enzyme function. Evidence of subclinical muscle involvement was frequently detected in patients with SORD-PN, including mildly to moderately elevated serum creatine kinase (CK) levels in 10 patients, myogenic electrophysiological changes in one patient, and muscle edema in five patients undergoing lower extremity MRI. Fasting serum sorbitol level was 88-fold higher in SORD-PN patients (9.69 ± 1.07 mg/L) than in healthy heterozygous subjects (0.11 ± 0.01 mg/L) and 138-fold higher than in healthy controls (0.07 ± 0.02 mg/L).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Interpretation</h3>\u0000 \u0000 <p>The novel <i>SORD</i> variant c.210 T > G;p.His70Gln and evidence of subclinical muscle involvement were identified, which expanded the genetic and clinical spectrum of SORD-PN. Subclinical muscle involvement might be a common but easily overlooked clinical feature. The serum CK and fasting serum sorbitol levels were expected to be sensitive biomarkers confirmed by follow-up cohort study.</p>\u0000 </section>\u0000 </div>","PeriodicalId":17451,"journal":{"name":"Journal of the Peripheral Nervous System","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2023-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10037154","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jun-Hui Yuan, Xiaoyang Cheng, Eiji Matsuura, Yujiro Higuchi, Masahiro Ando, Akihiro Hashiguchi, Akiko Yoshimura, Ryo Nakachi, Jun Mine, Takeshi Taketani, Kenichi Maeda, Saori Kawakami, Ryutaro Kira, Shoko Tanaka, Kazuaki Kanai, Fadia Dib-Hajj, Sulayman D. Dib-Hajj, Stephen G. Waxman, Hiroshi Takashima
Background and Aims
Voltage-gated sodium channel Nav1.7, encoded by the SCN9A gene, has been linked to diverse painful peripheral neuropathies, represented by the inherited erythromelalgia (EM) and paroxysmal extreme pain disorder (PEPD). The aim of this study was to determine the genetic etiology of patients experiencing neuropathic pain, and shed light on the underlying pathogenesis.
Methods
We enrolled eight patients presenting with early-onset painful peripheral neuropathies, consisting of six cases exhibiting EM/EM-like disorders and two cases clinically diagnosed with PEPD. We conducted a gene-panel sequencing targeting 18 genes associated with hereditary sensory and/or autonomic neuropathy. We introduced novel SCN9A mutation (F1624S) into a GFP-2A-Nav1.7rNS plasmid, and the constructs were then transiently transfected into HEK293 cells. We characterized both wild-type and F1624S Nav1.7 channels using an automated high-throughput patch-clamp system.
Results
From two patients displaying EM-like/EM phenotypes, we identified two SCN9A mutations, I136V and P1308L. Among two patients diagnosed with PEPD, we found two additional mutations in SCN9A, F1624S (novel) and A1632E. Patch-clamp analysis of Nav1.7-F1624S revealed depolarizing shifts in both steady-state fast inactivation (17.4 mV, p < .001) and slow inactivation (5.5 mV, p < .001), but no effect on channel activation was observed.
Interpretation
Clinical features observed in our patients broaden the phenotypic spectrum of SCN9A-related pain disorders, and the electrophysiological analysis enriches the understanding of genotype–phenotype association caused by Nav1.7 gain-of-function mutations.
{"title":"Genetic, electrophysiological, and pathological studies on patients with SCN9A-related pain disorders","authors":"Jun-Hui Yuan, Xiaoyang Cheng, Eiji Matsuura, Yujiro Higuchi, Masahiro Ando, Akihiro Hashiguchi, Akiko Yoshimura, Ryo Nakachi, Jun Mine, Takeshi Taketani, Kenichi Maeda, Saori Kawakami, Ryutaro Kira, Shoko Tanaka, Kazuaki Kanai, Fadia Dib-Hajj, Sulayman D. Dib-Hajj, Stephen G. Waxman, Hiroshi Takashima","doi":"10.1111/jns.12590","DOIUrl":"10.1111/jns.12590","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background and Aims</h3>\u0000 \u0000 <p>Voltage-gated sodium channel Nav1.7, encoded by the <i>SCN9A</i> gene, has been linked to diverse painful peripheral neuropathies, represented by the inherited erythromelalgia (EM) and paroxysmal extreme pain disorder (PEPD). The aim of this study was to determine the genetic etiology of patients experiencing neuropathic pain, and shed light on the underlying pathogenesis.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We enrolled eight patients presenting with early-onset painful peripheral neuropathies, consisting of six cases exhibiting EM/EM-like disorders and two cases clinically diagnosed with PEPD. We conducted a gene-panel sequencing targeting 18 genes associated with hereditary sensory and/or autonomic neuropathy. We introduced novel <i>SCN9A</i> mutation (F1624S) into a GFP-2A-Nav1.7rNS plasmid, and the constructs were then transiently transfected into HEK293 cells. We characterized both wild-type and F1624S Nav1.7 channels using an automated high-throughput patch-clamp system.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>From two patients displaying EM-like/EM phenotypes, we identified two <i>SCN9A</i> mutations, I136V and P1308L. Among two patients diagnosed with PEPD, we found two additional mutations in <i>SCN9A</i>, F1624S (novel) and A1632E. Patch-clamp analysis of Nav1.7-F1624S revealed depolarizing shifts in both steady-state fast inactivation (17.4 mV, <i>p</i> < .001) and slow inactivation (5.5 mV, <i>p</i> < .001), but no effect on channel activation was observed.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Interpretation</h3>\u0000 \u0000 <p>Clinical features observed in our patients broaden the phenotypic spectrum of <i>SCN9A</i>-related pain disorders, and the electrophysiological analysis enriches the understanding of genotype–phenotype association caused by Nav1.7 gain-of-function mutations.</p>\u0000 </section>\u0000 </div>","PeriodicalId":17451,"journal":{"name":"Journal of the Peripheral Nervous System","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2023-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10021484","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ophthalmological abnormalities have been reported in hereditary transthyretin-related amyloidosis (ATTRv, v for variant) but not in wild-type transthyretin-related amyloidosis (ATTRwt).
Methods
Patients with ATTRwt, ATTRv, and light chain amyloidosis (AL) and healthy subjects (controls) underwent complete eye examination, including optical coherence tomography (OCT), OCT angiography (OCTA), and in vivo corneal confocal microscopy (CCM).
Results
Seventeen ATTRwt, nine ATTRv, two ATTRv carriers, and seven AL patients were enrolled. Compared with other groups, ATTRwt patients had 10 letters lower visual acuity and a higher prevalence of glaucoma, cataract, and retinal pigment epithelium alterations. In the whole group of patients, especially in ATTRwt, we observed (1) a reduced corneal nerve fiber length and more tortuous stromal nerves at CCM, (2) a reduced macular volume and peripapillary nerve fiber layer thickness at OCT, and (3) impairment of peripapillary and macular vascularization at OCTA.
Interpretation
Ophthalmological abnormalities are common in ATTRwt, significantly impairing visual acuity. Noninvasive imaging modalities allow for the identification of small nerve fibers and small vessel damage, which may represent further warning signs for early diagnosis of ATTRwt.
{"title":"Ophthalmological involvement in wild-type transthyretin amyloidosis: A multimodal imaging study","authors":"Luisa Frizziero, Alessandro Salvalaggio, Eleonora Cosmo, Alberto Cipriani, Edoardo Midena, Chiara Briani","doi":"10.1111/jns.12589","DOIUrl":"10.1111/jns.12589","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background and Aims</h3>\u0000 \u0000 <p>Ophthalmological abnormalities have been reported in hereditary transthyretin-related amyloidosis (ATTRv, v for variant) but not in wild-type transthyretin-related amyloidosis (ATTRwt).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Patients with ATTRwt, ATTRv, and light chain amyloidosis (AL) and healthy subjects (controls) underwent complete eye examination, including optical coherence tomography (OCT), OCT angiography (OCTA), and in vivo corneal confocal microscopy (CCM).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Seventeen ATTRwt, nine ATTRv, two ATTRv carriers, and seven AL patients were enrolled. Compared with other groups, ATTRwt patients had 10 letters lower visual acuity and a higher prevalence of glaucoma, cataract, and retinal pigment epithelium alterations. In the whole group of patients, especially in ATTRwt, we observed (1) a reduced corneal nerve fiber length and more tortuous stromal nerves at CCM, (2) a reduced macular volume and peripapillary nerve fiber layer thickness at OCT, and (3) impairment of peripapillary and macular vascularization at OCTA.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Interpretation</h3>\u0000 \u0000 <p>Ophthalmological abnormalities are common in ATTRwt, significantly impairing visual acuity. Noninvasive imaging modalities allow for the identification of small nerve fibers and small vessel damage, which may represent further warning signs for early diagnosis of ATTRwt.</p>\u0000 </section>\u0000 </div>","PeriodicalId":17451,"journal":{"name":"Journal of the Peripheral Nervous System","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2023-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/jns.12589","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10135095","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. L. D. Tadenev, C. L. Hatton, B. Pattavina, T. Mullins, R. Schneider, L. P. Bogdanik, Robert W. Burgess
Background
Charcot–Marie–Tooth disease type 1X is caused by mutations in GJB1, which is the second most common gene associated with inherited peripheral neuropathy. The GJB1 gene encodes connexin 32 (CX32), a gap junction protein expressed in myelinating glial cells. The gene is X-linked, and the mutations cause a loss of function.
Aims
A large number of disease-associated variants have been identified, and many result in mistrafficking and mislocalization of the protein. An existing knockout mouse lacking Gjb1 expression provides a valid animal model of CMT1X, but the complete lack of protein may not fully recapitulate the disease mechanisms caused by aberrant CX32 proteins. To better represent the spectrum of human CMT1X-associated mutations, we have generated a new Gjb1 knockin mouse model.
Methods
CRISPR/Cas9 genome editing was used to produce mice carrying the R15Q mutation in Gjb1. In addition, we identified a second allele with an early frame shift mutation in codon 7 (del2). Mice were analyzed using clinically relevant molecular, histological, neurophysiological, and behavioral assays.
Results
Both alleles produce protein detectable by immunofluorescence in Schwann cells, with some protein properly localizing to nodes of Ranvier. However, both alleles also result in peripheral neuropathy with thinly myelinated and demyelinated axons, as well as degenerating and regenerating axons, predominantly in distal motor nerves. Nerve conduction velocities were only mildly reduced at later ages and compound muscle action potential amplitudes were not reduced. Levels of neurofilament light chain in plasma were elevated in both alleles. The del2 mice have an onset at ~3 months of age, whereas the R15Q mice had a later onset at 5–6 months of age, suggesting a milder loss of function. Both alleles performed comparably to wild type littermates in accelerating rotarod and grip strength tests of neuromuscular performance.
Interpretation
We have generated and characterized two new mouse models of CMT1X that will be useful for future mechanistic and preclinical studies.
{"title":"Two new mouse models of Gjb1-associated Charcot–Marie–Tooth disease type 1X","authors":"A. L. D. Tadenev, C. L. Hatton, B. Pattavina, T. Mullins, R. Schneider, L. P. Bogdanik, Robert W. Burgess","doi":"10.1111/jns.12588","DOIUrl":"10.1111/jns.12588","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background</h3>\u0000 \u0000 <p>Charcot–Marie–Tooth disease type 1X is caused by mutations in <i>GJB1</i>, which is the second most common gene associated with inherited peripheral neuropathy. The <i>GJB1</i> gene encodes connexin 32 (CX32), a gap junction protein expressed in myelinating glial cells. The gene is X-linked, and the mutations cause a loss of function.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Aims</h3>\u0000 \u0000 <p>A large number of disease-associated variants have been identified, and many result in mistrafficking and mislocalization of the protein. An existing knockout mouse lacking <i>Gjb1</i> expression provides a valid animal model of CMT1X, but the complete lack of protein may not fully recapitulate the disease mechanisms caused by aberrant CX32 proteins. To better represent the spectrum of human CMT1X-associated mutations, we have generated a new <i>Gjb1</i> knockin mouse model.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>CRISPR/Cas9 genome editing was used to produce mice carrying the R15Q mutation in <i>Gjb1</i>. In addition, we identified a second allele with an early frame shift mutation in codon 7 (del2). Mice were analyzed using clinically relevant molecular, histological, neurophysiological, and behavioral assays.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Both alleles produce protein detectable by immunofluorescence in Schwann cells, with some protein properly localizing to nodes of Ranvier. However, both alleles also result in peripheral neuropathy with thinly myelinated and demyelinated axons, as well as degenerating and regenerating axons, predominantly in distal motor nerves. Nerve conduction velocities were only mildly reduced at later ages and compound muscle action potential amplitudes were not reduced. Levels of neurofilament light chain in plasma were elevated in both alleles. The del2 mice have an onset at ~3 months of age, whereas the R15Q mice had a later onset at 5–6 months of age, suggesting a milder loss of function. Both alleles performed comparably to wild type littermates in accelerating rotarod and grip strength tests of neuromuscular performance.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Interpretation</h3>\u0000 \u0000 <p>We have generated and characterized two new mouse models of CMT1X that will be useful for future mechanistic and preclinical studies.</p>\u0000 </section>\u0000 </div>","PeriodicalId":17451,"journal":{"name":"Journal of the Peripheral Nervous System","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2023-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10555766","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jack R. Fennessy, Kayla M. D. Cornett, Joshua Burns, Manoj P. Menezes
Riboflavin transporter deficiency (RTD) is a progressive inherited neuropathy of childhood onset, characterised by pontobulbar palsy, sensorineural deafness, sensory ataxia, muscle weakness, optic atrophy and respiratory failure. Riboflavin supplementation is beneficial in short-term reports, but the quantum of benefit in various clinical domains is not well understood. A PubMed search was conducted, which identified 94 genetically confirmed cases of RTD who received riboflavin supplementation and had follow-up assessments. Information on the clinical and functional status before and after riboflavin supplementation was collected and analysed. Seventy-six of the 94 patients (80.9%) showed an overall improvement after riboflavin supplementation, and the remaining (19.1%) were stable, though some patients had deteriorations in individual domains with no reported deaths. The domains that had the highest rates of response to riboflavin supplementation were gross motor function (93.3% improved), bulbar palsy (91.3%) and ataxia (90.0%). Improvements were also seen in limb muscle weakness, audiology, facial nerve palsy and respiratory function. Despite treatment, many patients required assistance to ambulate and had severe or profound hearing loss and some remained gastrostomy or tracheostomy dependent. Riboflavin supplementation is a lifesaving intervention for patients with RTD and results in a profound improvement in several functional domains, with early diagnosis and treatment further improving outcomes. Despite treatment, patients are left with residual disability. There is a need to accurately measure functional outcomes in children with RTD and develop additional disease-modifying therapies.
{"title":"Benefit of high-dose oral riboflavin therapy in riboflavin transporter deficiency","authors":"Jack R. Fennessy, Kayla M. D. Cornett, Joshua Burns, Manoj P. Menezes","doi":"10.1111/jns.12587","DOIUrl":"10.1111/jns.12587","url":null,"abstract":"<p>Riboflavin transporter deficiency (RTD) is a progressive inherited neuropathy of childhood onset, characterised by pontobulbar palsy, sensorineural deafness, sensory ataxia, muscle weakness, optic atrophy and respiratory failure. Riboflavin supplementation is beneficial in short-term reports, but the quantum of benefit in various clinical domains is not well understood. A PubMed search was conducted, which identified 94 genetically confirmed cases of RTD who received riboflavin supplementation and had follow-up assessments. Information on the clinical and functional status before and after riboflavin supplementation was collected and analysed. Seventy-six of the 94 patients (80.9%) showed an overall improvement after riboflavin supplementation, and the remaining (19.1%) were stable, though some patients had deteriorations in individual domains with no reported deaths. The domains that had the highest rates of response to riboflavin supplementation were gross motor function (93.3% improved), bulbar palsy (91.3%) and ataxia (90.0%). Improvements were also seen in limb muscle weakness, audiology, facial nerve palsy and respiratory function. Despite treatment, many patients required assistance to ambulate and had severe or profound hearing loss and some remained gastrostomy or tracheostomy dependent. Riboflavin supplementation is a lifesaving intervention for patients with RTD and results in a profound improvement in several functional domains, with early diagnosis and treatment further improving outcomes. Despite treatment, patients are left with residual disability. There is a need to accurately measure functional outcomes in children with RTD and develop additional disease-modifying therapies.</p>","PeriodicalId":17451,"journal":{"name":"Journal of the Peripheral Nervous System","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2023-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/jns.12587","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10537716","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Luca Leonardi, Rocco Costanzo, Francesca Forcina, Stefania Morino, Giovanni Antonini, Marco Salvetti, Marco Luigetti, Angela Romano, Guido Primiano, Valeria Guglielmino, Laura Fionda, Matteo Garibaldi, Antonio Lauletta, Elena Rossini, Laura Tufano, Marco Ceccanti, Nicoletta Esposito, Pietro Falco, Giuseppe di Pietro, Andrea Truini, Eleonora Galosi
Hereditary transthyretin amyloidosis polyneuropathy (ATTRv‐PN) presymptomatic carriers often show preclinical abnormalities at small fiber‐related diagnostic tests. However, no validated biomarker is currently available to use for presymptomatic carriers' follow‐up, thus helping therapeutic decision making. Our study aimed at assessing nerve conduction study (NCS), quantitative sensory testing (QST), and skin biopsy parameters in a large cohort of late‐onset ATTRv presymptomatic carriers and to evaluate whether they correlated with predicted age of disease onset (PADO).
遗传性甲状腺转蛋白淀粉样变性多神经病变(ATTRv-PN)症状前携带者在小纤维相关诊断试验中经常表现出临床前异常。然而，目前还没有经过验证的生物标志物可用于症状前携带者的随访，从而帮助治疗决策。本研究旨在评估一大批迟发性ATTRv症状前携带者的神经传导研究(NCS)、定量感觉测试(QST)和皮肤活检参数，并评估它们是否与预测发病年龄(PADO)相关。方法连续招募迟发性atv症状前携带者，进行NCS、QST和皮肤活检，并从远端和近端评估表皮内神经纤维密度(IENFD)。采用双神经病变-4 (DN4)和小纤维神经病变-症状量表(SFN-SIQ)评估疼痛和小纤维神经病变相关症状。估计每个携带者的PADO和到达PADO的时间(delta-PADO)，并分析与诊断测试措施的相关性。结果入选症状前ATTRv受试者40例。20名携带者(50%)远端IENFD减少，73%的病例具有非长度依赖性分布。11名受试者(27.5%)在QST有冷和/或热检测阈值(CDT和/或WDT)异常。δ - pado与腓肠感觉神经动作电位(SNAP)振幅正相关(r =。416, p = .004)，而CDT等QST参数的z值(r =。314, p = 0.028)， WDT (r =−。294, p = 0.034)，机械检测阈值(MDT;r =−。382, p = .012)。简单线性回归模型显示δ - pado与患者SAP、CDT、MDT呈线性关系。结论:我们的研究结果证实，在ATTRv症状前携带者中，IENFD减少和QST异常可能发生在早期，通常具有非长度依赖模式。然而，只有总体SAP振幅和QST参数与delta-PADO相关，提示连续联合QST和NCS评估可用于atv症状前携带者的随访。
{"title":"Quantitative sensory testing and skin biopsy findings in late-onset ATTRv presymptomatic carriers: Relationships with predicted time of disease onset (PADO)","authors":"Luca Leonardi, Rocco Costanzo, Francesca Forcina, Stefania Morino, Giovanni Antonini, Marco Salvetti, Marco Luigetti, Angela Romano, Guido Primiano, Valeria Guglielmino, Laura Fionda, Matteo Garibaldi, Antonio Lauletta, Elena Rossini, Laura Tufano, Marco Ceccanti, Nicoletta Esposito, Pietro Falco, Giuseppe di Pietro, Andrea Truini, Eleonora Galosi","doi":"10.1111/jns.12586","DOIUrl":"10.1111/jns.12586","url":null,"abstract":"Hereditary transthyretin amyloidosis polyneuropathy (ATTRv‐PN) presymptomatic carriers often show preclinical abnormalities at small fiber‐related diagnostic tests. However, no validated biomarker is currently available to use for presymptomatic carriers' follow‐up, thus helping therapeutic decision making. Our study aimed at assessing nerve conduction study (NCS), quantitative sensory testing (QST), and skin biopsy parameters in a large cohort of late‐onset ATTRv presymptomatic carriers and to evaluate whether they correlated with predicted age of disease onset (PADO).","PeriodicalId":17451,"journal":{"name":"Journal of the Peripheral Nervous System","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2023-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/jns.12586","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10183239","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Marianna Di Egidio, Cristian R. Bacaglio, Rocio Arrejoría, Andrés M. Villa, Gustavo A. Nores, Pablo H. H. Lopez
Background and Aims
Multifocal motor neuropathy (MMN) is a peripheral nerve disorder characterized by slow progressive distal asymmetric weakness with minimal or no sensory impairment. Currently, a vast evidence supports a direct pathogenic role of IgM anti-GM1 antibodies on disease pathogenesis. Patients with MMN seropositive for GM1-specific IgM antibodies have significantly more weakness, disability and axon loss than patients without these antibodies. During the screening for IgM anti-GM1 antibodies in a cohort of patients with neuropathy we noticed an absence or significant reduction of natural IgM anti-GM1 autoreactivity in some patients with MMN, suggesting a mechanism of self-control of autoreactivity. We aim to understand the lack of natural reactivity against GM1 in MMN patients.
Methods
The presence of free IgM anti-GM1 reactivity or its complex to blocking IgG was analysed by combining high performance thin layer chromatography-immunostaining, soluble binding inhibition assays, Protein-G or GM1-affinity columns and dot blot assays.
Results
We identified in MMN patients an immunoregulation of IgM anti-GM1 antibodies mediated by IgG immunoglobulins characterized by: (i) lack of natural IgM anti-GM1 autoreactivity as a result of a immunoregulatory IgG-dependent mechanism; (ii) presence of natural and disease-associated IgM anti-GM1/IgG blocking Ab complexes in sera; and (iii) high levels of IgG blocking against natural IgM anti-GM1 antibodies (Abs.
Interpretation
Our observations unmask a spontaneous IgG-dependent mechanism of immunoregulation against IgM anti-GM1 antibodies that could explain, in part, fluctuations in the usually slowly progressive clinical course that characterizes the disease and, at the same time, allows the identification of an autoimmune response against GM1 ganglioside in seronegative patients.
{"title":"Evidence for spontaneous regulation of the humoral IgM anti-GM1 autoimmune response by IgG antibodies in multifocal motor neuropathy patients","authors":"Marianna Di Egidio, Cristian R. Bacaglio, Rocio Arrejoría, Andrés M. Villa, Gustavo A. Nores, Pablo H. H. Lopez","doi":"10.1111/jns.12583","DOIUrl":"10.1111/jns.12583","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background and Aims</h3>\u0000 \u0000 <p>Multifocal motor neuropathy (MMN) is a peripheral nerve disorder characterized by slow progressive distal asymmetric weakness with minimal or no sensory impairment. Currently, a vast evidence supports a direct pathogenic role of IgM anti-GM1 antibodies on disease pathogenesis. Patients with MMN seropositive for GM1-specific IgM antibodies have significantly more weakness, disability and axon loss than patients without these antibodies. During the screening for IgM anti-GM1 antibodies in a cohort of patients with neuropathy we noticed an absence or significant reduction of natural IgM anti-GM1 autoreactivity in some patients with MMN, suggesting a mechanism of self-control of autoreactivity. We aim to understand the lack of natural reactivity against GM1 in MMN patients.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>The presence of free IgM anti-GM1 reactivity or its complex to blocking IgG was analysed by combining high performance thin layer chromatography-immunostaining, soluble binding inhibition assays, Protein-G or GM1-affinity columns and dot blot assays.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>We identified in MMN patients an immunoregulation of IgM anti-GM1 antibodies mediated by IgG immunoglobulins characterized by: (i) lack of natural IgM anti-GM1 autoreactivity as a result of a immunoregulatory IgG-dependent mechanism; (ii) presence of natural and disease-associated IgM anti-GM1/IgG blocking Ab complexes in sera; and (iii) high levels of IgG blocking against natural IgM anti-GM1 antibodies (Abs.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Interpretation</h3>\u0000 \u0000 <p>Our observations unmask a spontaneous IgG-dependent mechanism of immunoregulation against IgM anti-GM1 antibodies that could explain, in part, fluctuations in the usually slowly progressive clinical course that characterizes the disease and, at the same time, allows the identification of an autoimmune response against GM1 ganglioside in seronegative patients.</p>\u0000 </section>\u0000 </div>","PeriodicalId":17451,"journal":{"name":"Journal of the Peripheral Nervous System","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2023-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10186265","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kanokporn Chayaburakul, Wei Yi Ong, Deron R. Herr, Phetnarin Kobutree, Kraisri Chantra
Background and Aims
Cisplatin is a chemotherapeutic agent for many types of cancer. The neurotoxicity of cisplatin includes neuropathy and allodynia. We aimed to study structural changes by using CYM54-78, attenuating cisplatin-induced neuropathy and blocking the pathogenesis in neurons, and promoting axonal regeneration.
Methods
TEM (transmission electron microscopy) was used to distinguish ultrastructural changes in dorsal root ganglion (DRG) and dorsal rootlets (DR) between rats treated with cisplatin alone and rats co-treated with cisplatin and sphingosine -1-phosphate receptor2 (S1P2) agonist, CYM-5478.
Results
In DRG of rats treated with cisplatin alone, TEM micrographs showed necrosis and apoptotic cells. Neuronal cytoplasm showed numerous vacuole (stage C) and swelling (stage B➔C) mitochondrial degeneration. Neurons in DRG from cisplatin+CYM-5478 group showed a higher percentage of healthy mitochondria (from 5.3% to 75.6%) than those treated with cisplatin alone. DR of cisplatin only group showed abnormal axoplasm, axolemma, and focal detached myelin sheaths, especially in Aδ (fast pain) and Aβ (touch) fibers, and revealed collateral branches that sprouted from Aβ fibers, which is characteristic of allodynia. Moreover, vasoconstriction was observed in DRG and DR. Rats in cisplatin+CYM-5478 group showed not only fewer abnormal structures than those in cisplatin only group, but also showed Bands of Büngner and onion bulb-like structures, which are characteristic of nerve regeneration.
Interpretation
Together with our previous study, showed that CYM-5478 attenuated neuropathy and allodynia in a rat model of cisplatin-induced neuropathy, these results suggest S1P2 agonists as a potential approach the for treatment of cancer due to the reduction of side effects of cisplatin.
{"title":"Differences in the ultrastructure of neurons in the spinal ganglion and dorsal rootlet between rats treated with cisplatin only versus co-administration with a sphingosine 1-phosphate receptor 2 agonist in attenuating neuropathy and allodynia","authors":"Kanokporn Chayaburakul, Wei Yi Ong, Deron R. Herr, Phetnarin Kobutree, Kraisri Chantra","doi":"10.1111/jns.12582","DOIUrl":"10.1111/jns.12582","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background and Aims</h3>\u0000 \u0000 <p>Cisplatin is a chemotherapeutic agent for many types of cancer. The neurotoxicity of cisplatin includes neuropathy and allodynia. We aimed to study structural changes by using CYM54-78, attenuating cisplatin-induced neuropathy and blocking the pathogenesis in neurons, and promoting axonal regeneration.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>TEM (transmission electron microscopy) was used to distinguish ultrastructural changes in dorsal root ganglion (DRG) and dorsal rootlets (DR) between rats treated with cisplatin alone and rats co-treated with cisplatin and sphingosine -1-phosphate receptor2 (S1P2) agonist, CYM-5478.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>In DRG of rats treated with cisplatin alone, TEM micrographs showed necrosis and apoptotic cells. Neuronal cytoplasm showed numerous vacuole (stage C) and swelling (stage B➔C) mitochondrial degeneration. Neurons in DRG from cisplatin+CYM-5478 group showed a higher percentage of healthy mitochondria (from 5.3% to 75.6%) than those treated with cisplatin alone. DR of cisplatin only group showed abnormal axoplasm, axolemma, and focal detached myelin sheaths, especially in Aδ (fast pain) and Aβ (touch) fibers, and revealed collateral branches that sprouted from Aβ fibers, which is characteristic of allodynia. Moreover, vasoconstriction was observed in DRG and DR. Rats in cisplatin+CYM-5478 group showed not only fewer abnormal structures than those in cisplatin only group, but also showed Bands of Büngner and onion bulb-like structures, which are characteristic of nerve regeneration.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Interpretation</h3>\u0000 \u0000 <p>Together with our previous study, showed that CYM-5478 attenuated neuropathy and allodynia in a rat model of cisplatin-induced neuropathy, these results suggest S1P2 agonists as a potential approach the for treatment of cancer due to the reduction of side effects of cisplatin.</p>\u0000 </section>\u0000 </div>","PeriodicalId":17451,"journal":{"name":"Journal of the Peripheral Nervous System","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2023-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10186254","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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