Journal of the Peripheral Nervous System最新文献

Background and Objectives

Hereditary sensory neuropathies (HSNs) are a group of genetically and clinically heterogeneous diseases. Our study aims to summarize the genetic and clinical features of HSNs in 10 Chinese families.

Methods

Clinical data from 10 families with HSNs were collected retrospectively. Genetic screening was performed by whole exome sequencing (WES). Repeated-primed PCR and capillary electrophoresis were performed for WES-negative patients to analyze repeat expansions in RFC1.

Results

Among the 10 probands with HSNs, eight cases were sporadic, and two had a positive family history. Six probands had early-onset (onset age < 20 years). Seven probands presented with pure-HSNs type, and three exhibited HSNs-complex type with ataxia. Variants in the NTRK1, SPTLC1, COX20, PUM1, and RFC1 genes were detected in six probands. A novel variant, c.444C>A (p.N148K), in NTRK1 was identified in an autosomal recessive inheritance family with HSAN-IV, and a novel variant, c.182dup (p.H61Qfs*31), in PUM1 was identified in a proband with adult-onset paresthesia and mild cerebellar ataxia. Additionally, biallelic expansion of the pathogenic variant structure (AAGGG)exp repeat amplification in the RFC1 gene was identified in a proband with sensory neuropathy, ataxia, and right vestibular hypofunction.

Conclusions

The novel variants in NTRK1 and PUM1 expanded the genotypic spectrum of HSNs. This study highlights the associations between sensory neuropathies and other symptoms, particularly cerebellar ataxia. Given the ultra-rarity of HSNs, future multicenter studies with larger cohorts may facilitate the identification of novel variants, improve genetic diagnostic rates, and enhance disease recognition.

Background

We conducted a survey to determine the current diagnosis and treatment of multifocal motor neuropathy (MMN) in the United Kingdom.

Methods

Demographic, diagnostic and treatment data were collected at nine UK neuroscience centres.

Results

Ninety-five subjects were included. Mean age at diagnosis was 49.9 years (SD: 11.4). Males were more commonly affected (ratio: 1.9:1). Diagnostic delay was > 1 year from the time of first neurological assessment, in > 50% of subjects. Applying modified EFNS/PNS 2010 criteria, 69/95 (72.6%) had definite MMN, 10/95 (10.5%) had probable MMN, 15/95 (15.8%) had possible MMN, through treatment responsiveness in 9/15 (60%) and 1/95 (1.1%) did not meet criteria. Cerebrospinal fluid examination, anti-GM1 antibody testing and brachial plexus magnetic resonance imaging were non-contributory. Immunoglobulin response was reported in 90/92 subjects (97.8%), and 84/90 (93.3%) remained on treatment after a mean of 9.4 years, at a mean dose of 26.2 g/week (range: 4–114). Mean long-term immunoglobulin dose was 30%–60% higher than reported in neighbouring countries. Contrasting with previous reports of frequent loss of immunoglobulin response and functional decline, our physician-assessed long-term outcome was favourable (stable or improving) in 74/84 (88.1%) treated subjects.

Interpretation

MMN diagnosis and treatment in the United Kingdom are comparable to that of neighbouring countries and follow existing guidelines. Diagnostic delay after the first neurological assessment is considerable. Electrophysiology shows at least one definite/probable conduction block in nearly 90% of cases. The mean long-term immunoglobulin dose is higher in the United Kingdom than reported elsewhere, although highly variable. Whether higher doses of immunoglobulin may improve long-term outcomes requires further study.

Background and Aims

Domino liver transplantation (DLT) has been used to address the shortage of donor organs. However, recipients of liver grafts from patients with hereditary transthyretin amyloidosis (ATTRv) develop de novo transthyretin (TTR) amyloidosis. Our aim is to describe the clinical presentation of patients with acquired TTR amyloidosis and compare the rate of neuropathy progression (NP) with untreated ATTRv amyloidosis with neuropathy (ATTRv-NP) patients.

Methods

Patients with acquired TTR amyloidosis after DLT followed at a reference centre were evaluated. Medical records were reviewed for clinical characterization and systematic assessment of neuropathy. NP was defined as an increase in neuropathy impairment score of the lower limbs (NIS-LL) at 12 months and compared to a historical control group of untreated ATTRv amyloidosis patients.

Results

Twenty-four patients with acquired ATTR amyloidosis were included. Time from DLT to neuropathy onset was 9 $��\pm �$ 2.0 years and the majority of patients reported feet sensory changes as first symptom. Thirteen patients with ≥ 2 evaluations with 12-months interval were analysed. Almost all patients developed a neuropathic phenotype with small nerve fibre involvement. Neuropathy progression was similar to untreated ATTRv-NP patients.

Interpretation

Recipients from liver grafts of ATTRv patients develop de novo amyloidosis with clinical presentation and NP similar to untreated ATTRv amyloidosis patients. Study of these patients might help elucidate the pathways for ATTR fibril formation.

Background and Aims

Nerve conduction studies (NCS) are integral to diagnosing chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), but their role in predicting treatment outcomes remains underexplored. This study evaluates NCS changes at first follow-up (first NCS changes) as predictors of treatment success in CIDP, focusing on their correlation with clinical outcomes over time.

Methods

Newly diagnosed CIDP patients meeting the 2021 EAN/PNS criteria were retrospectively evaluated. Baseline and first follow-up NCS parameters were compared with clinical outcomes, assessed by the Neuropathy Impairment Score (NIS) and Inflammatory Neuropathy Cause and Treatment (INCAT) disability score. All patients received first-line immunotherapy (intravenous immunoglobulin, corticosteroids, or plasma exchange).

Results

Of 39 treated patients, 26 (66.7%) were responders based on improving NIS trends, while 13 (33.3%) were nonresponders. Responders showed significant improvements at the first follow-up in fibular compound muscle action potential (CMAP) amplitude, ulnar CMAP amplitude, summated CMAP amplitudes, and fibular motor conduction velocity. Changes in fibular CMAP amplitude consistently correlated with NIS (R = −0.8 to −0.6, p ≤ 0.004) and INCAT disability score improvements (R = −0.6 to −0.3, p ≤ 0.032) across all follow-up intervals up to 60 months. Ulnar and summated CMAP amplitude changes also correlated with clinical outcomes, though their associations were less sustained than those of fibular CMAP amplitude.

Interpretation

The first change in fibular CMAP amplitude is a reliable biomarker for predicting CIDP treatment response, with ulnar and summated CMAP amplitudes as alternatives when the fibular response is absent. Our findings highlight the utility of first NCS changes in monitoring and predicting treatment outcomes in CIDP.

Background and Aims

Repeated cycles of demyelination and remyelination alter nerve tissue composition, likely affecting its material properties, including stiffness. Using ultrasound shear wave elastography (SWE), we assessed nerve shear wave velocity (SWV), a surrogate measure of stiffness, to determine its potential as a biomarker for demyelinating neuropathies, including chronic inflammatory demyelinating polyneuropathy, Charcot-Marie-Tooth type 1A, and anti-myelin-associated glycoprotein neuropathy.

Methods

This cross-sectional study compared nerve SWV between 20 patients with demyelinating neuropathies (60.2 ± 13.1 years) and 16 age-matched controls (56.8 ± 10.8 years). Each participant underwent bilateral SWE of the proximal and distal segments of four peripheral nerves in the upper (median, ulnar and radial) and lower (sciatic-tibial) limbs. Measurements were conducted in different limb positions to mimic two nerve tensile states, yielding a total of 32 nerve stiffness measurements per participant. Conventional nerve cross-sectional area was further evaluated for each nerve and location.

Results

Individuals with demyelinating polyneuropathy exhibited increased nerve SWV compared to age-matched controls (mean difference = 0.7 m/s, 95%CI [0.5 to 0.9]; p < 0.0001). This difference was observed across all nerves and regions, with the largest difference noted in the tibial. Axial nerve tension amplified these differences. Additionally, moderate to high negative correlations were observed between motor nerve conduction and nerve SWV.

Interpretation

This study identifies significant neuropathy-associated alterations in peripheral nerve elasticity. Our findings suggest that nerve stiffness could be a promising biomarker for demyelinating neuropathies, and provide a basis for the development of standardized peripheral nerve SWE protocols.

Background and Aims

Guillain-Barré syndrome (GBS) is a rare disorder, with a global incidence ranging from 1 to 2 individuals per 100,000 people/year. Infections and vaccines have been implicated as causes triggering GBS. The aim of the study was to identify host genes involved in the pathogenesis of GBS when Zika (ZIKV) and Chikungunya viruses (CHIKV) were introduced in Brazil.

Methods

A case–control study of GBS was performed when ZIKV and CHIKV were introduced into a naïve population. GBS was studied during both acute and postacute phases. RNA sequencing was conducted using whole blood.

Results

GBS typically manifested a week after rash and fever; acute inflammatory demyelinating polyradiculoneuropathy was more frequent. None of the GBS cases had a poor outcome. Serological assays for ZIKV and CHIKV revealed high titers of immunoglobulin G for both viruses in 9 out of 11 subjects. Metatranscriptomic analyses unveiled an increased abundance of reads attributed to Pseudomonas tolaasii and Toxoplasma gondii in the acute phase. Analysis of differentially expressed host genes during the acute phase revealed altered expression of genes associated with axogenesis, synapse assembly, and presynapse organization. Moreover, genes upregulated during acute GBS were primarily related to inflammation and the inflammasome pathways, including AIM2, NLR family genes and LRR-protein genes, and IL-10.

Interpretation

These findings suggest that inflammasome activation via AIM2 could play a role in tissue damage during GBS. Further investigation into the general activation of innate inflammatory responses is warranted to elucidate their potential contribution to the pathology of GBS.

Background and Aims

Multifocal motor neuropathy (MMN) and chronic inflammatory demyelinating polyneuropathy (CIDP) are immune-mediated neuropathies characterized by muscle weakness and/or sensory deficits. Identifying treatment response, relapse, and stability can be challenging in these chronic, sometimes unpredictable, conditions. This study explores the potential of a monitoring app designed to address these challenges.

Methods

Patients were monitored weekly or monthly, based on stability and patient preference, using grip strength, modified timed-up-and go (mTUG), and patient-reported outcome measures (PROMs). User experience was evaluated via a questionnaire addressing content and ease of use (scale 0–10). Adherence was measured as the percentage of completed mandatory assessments. We investigated reliability using intra-class correlation coefficients (ICCs) and standard errors of the mean (SEM) of repeated measurements. Longitudinal changes were analyzed using linear mixed-effects models.

Results

We included 38 patients, with a mean follow-up of 11 months (IQR 4.6–19.5). The mean user experience score was 8.35/10 (range 7–10). Adherence was 93% (95% CI: 91.9%–94.1%). Reported remote measurements for grip strength were 1358/1468 (93%), and 1343/1430 (94%) for mTUG. Grip strength and mTUG ICCs were both 0.96 (95% CI: 0.93–0.98 and 0.92–0.99, respectively). The average SEM was 8.46% (95% CI: 6.58–10.28) for grip strength and 8.18% (95% CI: 6.12–10.41) for mTUG. Only grip strength changed significantly, increasing by 3.1 pounds per 6 months (95% CI: 0.61–5.83; p = 0.016).

Interpretation

Our study demonstrates that tele-neuromonitoring is feasible and reliable, showing high adherence, positive user experience and high ICCs. We anticipate tele-neuromonitoring could complement routine follow-up, enabling clinicians to make better-informed treatment decisions.

Background and Aims

Leucine Zipper 4 (LUZP4)-immunoglobulin G (IgG) is a novel antibody implicated in germ cell tumor-related paraneoplastic neurologic syndrome. We report a case of painful, progressive tetraparesis associated with testicular seminoma and LUZP4-IgG seropositivity.

Case Report

A 51-year-old male presented with a 5-week history of lower limb predominant progressive weakness. Nerve conduction studies (NCS) and electromyography (EMG) revealed a subacute axonal polyradiculoneuropathy. MRI lumbar spine showed thickening of the cauda equina and enhancement of the lower thoracic spinal cord/conus. Cerebrospinal fluid (CSF) showed a lymphocytic pleocytosis, three oligoclonal bands, and mildly elevated protein. Initial treatment with intravenous immunoglobulin (IVIG) and prednisone produced temporary improvement. CT targeted retroperitoneal lymph node biopsy revealed a seminoma, which was treated with orchiectomy and chemotherapy. The testicular tissue was consistent with a regressed germ cell tumor. His course was subsequently refractory to IVIG, prednisone, and plasma exchange. LUZP4 antibodies were detected in serum, prompting treatment with cyclophosphamide and prednisone. At the 4-month follow-up, the patient had significant improvement in hand strength and had transitioned from walker to cane.

Interpretation

LUZP4-IgG seropositivity and identification of retroperitoneal seminoma confirmed a paraneoplastic neurologic syndrome, which is a CD8+ T-cell-mediated disorder. Aggressive immunotherapy was initiated, resulting in clinical improvement. This case underscores the importance of identifying specific serologic biomarkers that can inform therapeutic decisions and improve outcomes.

Background and Aims

At the neuromuscular junction (NMJ), the synapse between motor neurons and muscle fibers, reside perisynaptic Schwann cells (PSCs) which are specialized glia that regulate the maintenance and repair of this synapse. While we know how PSC morphology and numbers change in aging and various neuromuscular disorders that adversely affect the NMJ, the molecular mechanisms that alter PSC functions remain unknown. In this study, we investigated whether MEGF10 in PSCs modulates NMJ stability in developing, healthy young adult, middle-aged, and axotomized mice. MEGF10 is a glial phagocytic receptor that is enriched in PSCs compared to other Schwann cells (SCs).

Methods

We isolated PSCs from a transgenic reporter mouse line to assess Megf10 expression at different ages and following nerve injury using qPCR. We then used a conditional mouse lacking Megf10 in all SCs, including PSCs (Megf10 SC-KO mice). We examined NMJs and axonal debris clearance in Megf10 SC-KO mice using confocal microscopy.

Results

We found that Megf10 expression in PSCs peaks during development and decreases during aging and following denervation of NMJs. NMJs were morphologically normal in developing and young adult Megf10 SC-KO mice. This was not the case in middle-aged Megf10 SC-KO mice, in which NMJs presented with fewer PSCs, decreased PSC coverage of the endplate, and decreased innervation in comparison to control mice. Following nerve injury-induced damage, axonal debris at the NMJ was cleared faster in Megf10 SC-KO mice; yet, the rate of reinnervation was unchanged compared to control mice.

Interpretation

The data in this study suggest that MEGF10 in PSCs functions to maintain PSC number and NMJ innervation during aging. This study also suggests important roles for MEGF10 in mediating the clearance of axonal debris at NMJs following nerve injury.

Objectives

There are currently no FDA-approved disease-modifying therapies for diabetic peripheral neuropathy (DPN). We evaluated the effect of the sodium-glucose cotransporter 2 inhibitor (SGLT2i) dapagliflozin in Type 2 diabetes mellitus (T2DM) with DPN.

Research Design and Methods

In this prospective, open-label, randomised, controlled study, 40 participants with DPN were randomised to receive add-on 10 mg dapagliflozin OD (Group A) to existing oral antidiabetic drugs (OAD) (n = 22) or continue OADs as a standard of care (Group B) (n = 18). Participants underwent assessment of neuropathic symptoms and signs (MNSI), vibration perception threshold (VPT), corneal confocal microscopy (CCM) to quantify corneal nerve fibre density (CNFD), corneal nerve branch density (CNBD) and corneal nerve fibre length (CNFL) and skin biopsy to assess intraepidermal nerve fibre density (IENFD) and plasma markers of oxidative stress at randomisation and after 6 months.

Results

HbA1c decreased in Group A (p = 0.002) and Group B (p = 0.003), with no change in weight, body mass index (BMI) or lipids. Total MNSI increased in Group A (p = 0.01) with no change in Group B (p = 0.06). IENFD increased significantly in Group A (p = 0.01) and Group B (p = 0.01), while CNFD (p = 0.002), CNBD (p < 0.001) and CNFL (p = 0.025) increased in Group A with no change in Group B. There was a significant increase in glutathione peroxidase (p = 0.02) in Group A with no change in Group B, and a decrease in malondialdehyde in both groups (p < 0.001).

Conclusions

In participants with T2DM and DPN, dapagliflozin was associated with small nerve fibre regeneration and improvement in markers of oxidative stress.

Trial Registration: Clinical Trial Registry India, CRTI Reg. No (CTRI/2022/06/043236); ClinicalTrials.gov Identifier: NCT05162690