Confounding clinical presentation and different disease progression in CMT4B1.

We report seven Charcot-Marie-Tooth 4B1 (CMT4B1) patients from four families with distinctive features, presenting with severe distal weakness and cranial nerve involvement. Patient from family 1 presented with congenital varus foot deformity, progressive distal and proximal weakness leading to loss of ambulation at 14 years, bilateral facial palsy and prominent bulbar involvement. In three siblings from family 2, still ambulant in the second decade, neuropathy was associated with marked sweating and Arnold-Chiari syndrome. Patient from family 3, wheelchair-bound by 17 years, suffered from recurrent intestinal occlusion due to a mesenteric malformation. Patients from family 4, wheelchair-bound from age 6 years, were first diagnosed with type 1 Usher syndrome with congenital deafness and retinitis pigmentosa. CMT4B1 diagnosis was based upon suggestive clinical features and confirmed by the presence of recessive mutations in the MTMR2 gene. Our results expand the genetic and phenotypic spectrum of CMT4B1, which may include autonomic system involvement.

Are PSP patients included in clinical trials representative of the general PSP population?

BACKGROUND: Progressive supranuclear palsy (PSP) is a rare parkinsonian syndrome with a wide spectrum of clinical presentations. Recently, the MDS published revised diagnosis criteria to provide early and reliable diagnosis of PSP and its variants. Two large randomized clinical trials were initiated in 2017, but the question remains regarding the extrapolation of their results to the general PSP population. OBJECTIVE: To determine if PSP patients included in clinical trials are representative of the general PSP population. METHODS: We conducted a single center retrospective study of PSP patients referred to a tertiary department of Neurology (Pitié-Salpêtrière Hospital, Paris) for clinical diagnosis and clinical trial inclusion, over a 12-month period. We collected and analyzed gender, age at examination, age at disease onset, disease duration, and core clinical features regarding oculo-motor dysfunction, postural instability, akinesia and cognitive dysfunction, and inclusion/exclusion criteria of clinical trials to assess eligibility for inclusion. We assessed the relative proportions of different PSP subtypes, as defined by the MDS-PSP criteria, in the whole population compared to patients eligible in trials. RESULTS: 206 PSP patients were included, among which 175 (85%) were diagnosed with probable PSP-Richardson's syndrome (RS) subtype, with a mean age of 73 and mean disease duration of 5 years. Among those patients, 29 (21%) were eligible (age 71 ±â€¯10.7, disease duration 3.1 ±â€¯1.2 years) and 19 were included in trials, all with a diagnosis of probable PSP-RS. As compared to the whole population, patients included in clinical trials tended to be younger, and showed more PSP-RS subtypes (p < 0.05). CONCLUSION: The PSP population included in trials is very similar to the general PSP population, but younger, with shorter disease duration. By definition, only probable PSP subtypes are included in clinical trials. The time window for inclusion is short because of diagnosis delay, fast disease progression and old age of the population.

A multicenter retrospective study of charcot-marie-tooth disease type 4B (CMT4B) associated with mutations in myotubularin-related proteins (MTMRs).

OBJECTIVE: Charcot-Marie-Tooth (CMT) disease 4B1 and 4B2 (CMT4B1/B2) are characterized by recessive inheritance, early onset, severe course, slowed nerve conduction, and myelin outfoldings. CMT4B3 shows a more heterogeneous phenotype. All are associated with myotubularin-related protein (MTMR) mutations. We conducted a multicenter, retrospective study to better characterize CMT4B. METHODS: We collected clinical and genetic data from CMT4B subjects in 18 centers using a predefined minimal data set including Medical Research Council (MRC) scores of nine muscle pairs and CMT Neuropathy Score. RESULTS: There were 50 patients, 21 of whom never reported before, carrying 44 mutations, of which 21 were novel and six representing novel disease associations of known rare variants. CMT4B1 patients had significantly more-severe disease than CMT4B2, with earlier onset, more-frequent motor milestones delay, wheelchair use, and respiratory involvement as well as worse MRC scores and motor CMT Examination Score components despite younger age at examination. Vocal cord involvement was common in both subtypes, whereas glaucoma occurred in CMT4B2 only. Nerve conduction velocities were similarly slowed in both subtypes. Regression analyses showed that disease severity is significantly associated with age in CMT4B1. Slopes are steeper for CMT4B1, indicating faster disease progression. Almost none of the mutations in the MTMR2 and MTMR13 genes, responsible for CMT4B1 and B2, respectively, influence the correlation between disease severity and age, in agreement with the hypothesis of a complete loss of function of MTMR2/13 proteins for such mutations. INTERPRETATION: This is the largest CMT4B series ever reported, demonstrating that CMT4B1 is significantly more severe than CMT4B2, and allowing an estimate of prognosis. ANN NEUROL 2019.

Human diaphragm atrophy in amyotrophic lateral sclerosis is not predicted by routine respiratory measures.

Amyotrophic lateral sclerosis (ALS) patients show progressive respiratory muscle weakness leading to death from respiratory failure. However, there are no data on diaphragm histological changes in ALS patients and how they correlate with routine respiratory measurements.We collected 39 diaphragm biopsies concomitantly with laparoscopic insertion of intradiaphragmatic electrodes during a randomised controlled trial evaluating early diaphragm pacing in ALS (https://clinicaltrials.gov; NCT01583088). Myofibre type, size and distribution were evaluated by immunofluorescence microscopy and correlated with spirometry, respiratory muscle strength and phrenic nerve conduction parameters. The relationship between these variables and diaphragm atrophy was assessed using multivariate regression models.All patients exhibited significant slow- and fast-twitch diaphragmatic atrophy. Vital capacity (VC), maximal inspiratory pressure, sniff nasal inspiratory pressure (SNIP) and twitch transdiaphragmatic pressure did not correlate with the severity of diaphragm atrophy. Inspiratory capacity (IC) correlated modestly with slow-twitch myofibre atrophy. Supine fall in VC correlated weakly with fast-twitch myofibre atrophy. Multivariate analysis showed that IC, SNIP and functional residual capacity were independent predictors of slow-twitch diaphragmatic atrophy, but not fast-twitch atrophy.Routine respiratory tests are poor predictors of diaphragm structural changes. Improved detection of diaphragm atrophy is essential for clinical practice and for management of trials specifically targeting diaphragm muscle function.

Naftazone in advanced Parkinson's disease: An acute L-DOPA challenge randomized controlled trial.

INTRODUCTION: There is an unmet need to better control motor complications in Parkinson's disease (PD). Naftazone, which exhibits glutamate release inhibition properties, has shown antiparkinsonian and antidyskinetic activity in preclinical models of PD and in a clinical proof of concept study. METHODS: We conducted a double-blind randomized placebo-controlled cross-over trial in PD patients with motor fluctuations and dyskinesia testing naftazone 160 mg/day versus placebo for 14 days. The two co-primary endpoints were the area under curve (AUC) of motor (MDS-UPDRS part III) and dyskinesia (AIMS) scores during an acute levodopa challenge performed at the end of each period. Secondary endpoints were UDysRS and axial symptoms scores during the challenge; AIMS, UDysRS, and time spent with or without dyskinesia the day before the challenge. The primary analysis was performed in the per protocol population. RESULTS: Sixteen patients were included in the analysis. There was no difference between naftazone and placebo for the AUC of MDS-UPDRS III (-89, 95%CI[-1071; 893], p = 0.85), and AIMS (70, 95%CI[-192; 332], p = 0.57). At the end of treatment periods, AIMS score tended to be lower with naftazone than placebo (4.4 ±â€¯3.4 versus 6.7 ±â€¯4.4, p = 0.07), but UDysRS scores and other secondary outcomes were not different. Naftazone was safe and well tolerated. CONCLUSIONS: This study did not confirm previous results on the efficacy of naftazone on dyskinesia nor motor fluctuations highlighting the problem of translating results obtained in preclinical models into clinical trials. Further investigation of naftazone may be conducted in PD with longer treatment duration.

Multifocal motor neuropathy.

PURPOSE OF REVIEW: Multifocal motor neuropathy (MMN) has specific clinical and electrophysiologic features but can be difficult to diagnose if cases are not typical. Intravenous immunoglobulin (IVIg) remains the core initial and long-term treatment. In this review, recent advances in the diagnosis, monitoring and treatment of MMN are discussed. RECENT FINDINGS: The pathology of MMN likely depends on immune-mediated attack of the nodes of Ranvier and paranodal regions leading to conduction block. Antiganglioside antibodies are present in over 50% of patients. The sensitivity of antibody detection can be improved by testing for GM1/galactocerebroside (GM1/GalC) complexes. Complement activation plays a key role in the pathophysiology of MMN. Subcutaneous immunoglobulins are an efficacious alternative to IVIg for maintenance therapy in MMN. Complement inhibitor eculizumab may be a potential future treatment, but further studies are necessary. SUMMARY: The European Federation of Neurological Societies (EFNS)/Peripheral Nerve Society (PNS) guidelines for the diagnosis of MMN are currently widely used but probably need revision. Nerve ultrasound and plexus/nerve MRI can be helpful in diagnostic dilemmas. Monitoring of disease and response to treatment may improve using disease-specific evaluation scales such as MMN-Rasch-built overall disability scale. Further research into the pathophysiology of MMN is necessary to direct future treatment strategies.

N-hexane exposure: a cause of small fiber neuropathy.

A 59-year-old woman presented with progressive paresthesias of all of her limbs for 4 years, associated with neuropathic pain, tingling in the tongue and allodynia, consistent with small fiber neuropathy (SFN). Several systemic symptoms and signs were found on clinical examination and laboratory work-up. Neurological investigations including neurophysiologic test and skin biopsy supported the diagnosis of SFN. Chronic exposure to N-hexane was then disclosed and suspected to be the cause of the disease. Following the discontinuation of chronic N-hexane exposure, the patient had a progressive improvement of all signs and symptoms, reinforcing the correlation between exposure to N-hexane, and development of SFN. Exposure to N-hexane may be considered as a novel reversible cause of SFN, which underlines the need to look for toxic etiologies in the diagnosis of SFN.

Correction: Cervical Spinal Cord Atrophy Profile in Adult SMN1-Linked SMA.

[This corrects the article DOI: 10.1371/journal.pone.0152439.].

Cervical Spinal Cord Atrophy Profile in Adult SMN1-Linked SMA.

PURPOSE: The mechanisms underlying the topography of motor deficits in spinal muscular atrophy (SMA) remain unknown. We investigated the profile of spinal cord atrophy (SCA) in SMN1-linked SMA, and its correlation with the topography of muscle weakness. MATERIALS AND METHODS: Eighteen SMN1-linked SMA patients type III/V and 18 age/gender-matched healthy volunteers were included. Patients were scored on manual muscle testing and functional scales. Spinal cord was imaged using 3T MRI system. Radial distance (RD) and cord cross-sectional area (CSA) measurements in SMA patients were compared to those in controls and correlated with strength and disability scores. RESULTS: CSA measurements revealed a significant cord atrophy gradient mainly located between C3 and C6 vertebral levels with a SCA rate ranging from 5.4% to 23% in SMA patients compared to controls. RD was significantly lower in SMA patients compared to controls in the anterior-posterior direction with a maximum along C4 and C5 vertebral levels (p-values < 10-5). There were no correlations between atrophy measurements, strength and disability scores. CONCLUSIONS: Spinal cord atrophy in adult SMN1-linked SMA predominates in the segments innervating the proximal muscles. Additional factors such as neuromuscular junction or intrinsic skeletal muscle defects may play a role in more complex mechanisms underlying weakness in these patients.

Natural History of Cardiac and Respiratory Involvement, Prognosis and Predictive Factors for Long-Term Survival in Adult Patients with Limb Girdle Muscular Dystrophies Type 2C and 2D.

BACKGROUND: Type 2C and 2D limb girdle muscular dystrophies (LGMD) are a group of autosomal recessive limb girdle muscular dystrophies manifested by proximal myopathy, impaired respiratory muscle function and cardiomyopathy. The correlation and the prognostic impact of respiratory and heart impairment are poorly described. We aimed to describe the long-term cardiac and respiratory follow-up of these patients and to determine predictive factors of cardio-respiratory events and mortality in LGMD 2C and 2D. METHODS: We reviewed the charts of 34 LGMD patients, followed from 2005 to 2015, to obtain echocardiographic, respiratory function and sleep recording data. We considered respiratory events (acute respiratory failure, pulmonary sepsis, atelectasis or pneumothorax), cardiac events (acute heart failure, significant cardiac arrhythmia or conduction block, ischemic stroke) and mortality as outcomes of interest for the present analysis. RESULTS: A total of 21 patients had type 2C LGMD and 13 patients had type 2D. Median age was 30 years [IQR 24-38]. At baseline, median pulmonary vital capacity (VC) was 31% of predicted value [20-40]. Median maximal inspiratory pressure (MIP) was 31 cmH2O [IQR 20.25-39.75]. Median maximal expiratory pressure (MEP) was 30 cm H2O [20-36]. Median left ventricular ejection fraction (LVEF) was 55% [45-64] with 38% of patients with LVEF <50%. Over a median follow-up of 6 years, we observed 38% respiratory events, 14% cardiac events and 20% mortality. Among baseline characteristics, LVEF and left ventricular end diastolic diameter (LVEDD) were associated with mortality, whilst respiratory parameters (VC, MIP, MEP) and the need for home mechanical ventilation (HMV) were associated with respiratory events. CONCLUSION: In our cohort of severely respiratory impaired type 2C and 2D LGMD, respiratory morbidity was high. Cardiac dysfunction was frequent in particular in LGMD 2C and had an impact on long-term mortality. TRIAL REGISTRATION: ClinicalTrials.gov NCT02501083.

Long-term efficacy of rituximab in IgM anti-myelin-associated glycoprotein neuropathy: RIMAG follow-up study.

The Rituximab vs. Placebo in Polyneuropathy Associated With Anti-MAG IgM Monoclonal Gammopathy (RIMAG) study showed no improvement using the inflammatory neuropathy cause and treatment sensory score (ISS) as primary outcome in patients with IgM anti-myelin-associated glycoprotein neuropathy (IgM anti-MAG neuropathy) treated with rituximab, when compared with placebo. However, some secondary outcomes seemed to improve in the per protocol analysis. Patients from one participating center in the RIMAG study underwent a new evaluation after a median follow-up of 6 (interquartile range (IQR) 4.9; 6.5) years, using the same outcome measures used in the original study. Data were recorded in seven rituximab patients (group 1) and in eight placebo patients (group 2). In group 2, six of eight patients received immunotherapy during follow-up, while only two of seven did in group 1. No significant change was observed in either the ISS or the secondary outcomes in both groups, with the exception of worsening in the 10-m walk time in group 2 (p = 0.016). The RIMAG follow-up study failed to find any significant change in most outcome measures in patients from the RIMAG study, some of them having received new immunotherapies. This study stresses the lack of useful clinical scales sensitive enough to capture small, even meaningful, improvement in IgM anti-MAG neuropathy.

Immunotherapy in Peripheral Neuropathies.

Immunotherapy has been investigated in a small subset of peripheral neuropathies, including an acute one, Guillain-Barré syndrome, and 3 chronic forms: chronic inflammatory demyelinating polyradiculoneuropathy, multifocal motor neuropathy, and neuropathy associated with IgM anti-myelin-associated glycoprotein. Several experimental studies and clinical data are strongly suggestive of an immune-mediated pathogenesis. Either cell-mediated mechanisms or antibody responses to Schwann cell, compact myelin, or nodal antigens are considered to act together in an aberrant immune response to cause damage to peripheral nerves. Immunomodulatory treatments used in these neuropathies aim to act at various steps of this pathogenic process. However, there are many phenotypic variants and, consequently, there is a significant difference in the response to immunotherapy between these neuropathies, as well as a need to improve our knowledge and long-term management of chronic forms.

The pathogenesis of multifocal motor neuropathy and an update on current management options.

Multifocal motor neuropathy (MMN) is a rare and disabling disease. Several experimental studies and clinical data are strongly suggestive of an immune-mediated pathogenesis, although underlying mechanisms in MMN seem to be very specific, mainly because of the presence of IgM anti-GM1 serum antibodies and the dramatic response to intravenous immunoglobulins (IVIg). The origin of antiganglioside antibodies and the way in which they act at the molecular level remain unclear. Several studies have demonstrated the key role of complement activation in the underlying mechanisms of MMN, as well as in animal models of acute motor axonal neuropathy (AMAN). Deposition of the membrane attack complex may disrupt the architecture of the nodes of Ranvier and paranodal areas, causing local disruption of nodal sodium-channel clusters. In patients with MMN, muscle weakness is the consequence of conduction blocks (CB), which leads to secondary axonal degeneration, consequently the aim of the treatment is to reverse CB at early stages of the disease. High-dose immunoglobulin is to date the only therapy which has proven efficacy in MMN patients in providing transient improvement of muscle strength, but long-term follow-up studies show a progressive motor decline. Therefore, other therapies are needed to improve the conduction nerve properties in long-term design. The reduction of complement activation and more generally the gain in paranodal stabilization could be directions for future therapeutic strategies.

Multifocal motor neuropathy.

PURPOSE OF REVIEW: Multifocal motor neuropathy (MMN) remains a difficult issue for neurologists, as its clinical and electrophysiological presentation may be atypical, and because no alternative treatment to periodic immunoglobulin infusions has been assessed in its long-term management. This review intends to summarize the most recent advances in the diagnosis and treatment of MMN. RECENT FINDINGS: Recent reports have focused on atypical onset and unusual clinical presentation. Several sophisticated electrophysiological techniques, as triple stimulation, may help establish the presence of conduction blocks, as well as MRI findings. A recent immunological study focused on the detection of serum IgM binding to NS6S heparin disaccharide. In another research article, it was proposed that the use of combinatorial glycoarray or ELISA may increase the diagnostic sensitivity of antiglycolipid antibody testing. Subcutaneous immunoglobulin may represent an interesting alternative option to intravenous immunoglobulin. Lastly, recently reported open-label clinical trials with complement inhibitors and anti-CD20 monoclonal antibody may constitute a first step for further developments. SUMMARY: Diagnostic criteria for MMN are well established, but challenging situations still occur. Progresses in neurophysiologic and other laboratory tests may help in clarifying doubtful diagnoses. Current research into the pathophysiology of MMN is required to determine the future treatment targets.

Multifocal motor neuropathy.

Multifocal motor neuropathy (MMN) is a chronic immune-mediated neuropathy that is particular for its asymmetric, multifocal, purely motor clinical presentation, often related to the distribution of individual nerves. Upper limbs are usually primarily and more severely affected, but lower limbs may be involved during the course of the disease. The hallmark of the disease is the presence, in electrophysiological studies, of persistent conduction blocks in the affected motor nerves, located outside the usual sites of nerve compression, contrasting with normal sensory nerve conduction velocities. The most typical laboratory finding is the presence of high levels of serum IgM antibodies to the ganglioside GM1, and less frequently to asialo-GM1, GD1a or GM2. These striking features may help distinguishing this neuropathy from both motor neuron disease and other chronic immune-mediated neuropathies. Several randomized controlled trials (RCT) have established the efficacy of high-dose intravenous immunoglobulin (IVIg), as well as subcutaneous immunoglobulin (SCIg). However, this therapy has a short-lasting effect, and need to be maintained with periodic infusions. This disappointing status has led to the search of other immune therapies whose efficacy has not been so far confirmed in RCT. This review intends to summarize current contents in the diagnosis and the treatment of MMN.

Innate defensive behaviour and panic-like reactions evoked by rodents during aggressive encounters with Brazilian constrictor snakes in a complex labyrinth: behavioural validation of a new model to study affective and agonistic reactions in a prey versus predator paradigm.

Defensive behaviour has been extensively studied, and non-invasive methodologies may be interesting approaches to analyzing the limbic system function as a whole. Using experimental models of animals in the state of anxiety has been fundamental in the search for new anxiolytic and antipanic compounds. The aim of this present work is to examine a new model for the study of affective behaviour, using a complex labyrinth consisting of an arena and galleries forming a maze. Furthermore, it aims to compare the defensive behaviour of Wistar rats, Mongolian gerbils and golden hamsters in a complex labyrinth, as well as the defensive behaviour of Meriones unguiculatus in aggressive encounters with either Epicrates cenchria assisi or Boa constrictor amarali in this same model. Among species presently studied, the Mongolian gerbils showed better performance in the exploration of both arena and galleries of the labyrinth, also demonstrating less latency in finding exits of the galleries. This increases the possibility of survival, as well as optimizes the events of encounter with the predator. The duration of alertness and freezing increased during confrontation with living Epicrates, as well as the duration of exploratory behaviour in the labyrinth. There was an increase in the number of freezing and alertness behaviours, as well as in duration of alertness during confrontations involving E.c. assisi, compared with behavioural reactions elicited by jirds in presence of B.c. amarali. Interestingly, the aggressive behaviour of Mongolian gerbils was more prominent against B.c. amarali compared with the other Boidae snake. E.c. assisi elicited more offensive attacks and exhibited a greater time period of body movement than B.c. amarali, which spent more time in the arena and in defensive immobility than the E.c. assisi. Considering that jirds evoked more fear-like reaction in contact with E.c. assisi, a fixed E.c. assisi kept in a hermetically closed acrylic box was used as control. In these prey/predator encounter-based experiments, there was an increase in the number of alertness and freezing behaviours exhibited by gerbils, and a decrease in the number of crossing elicited by them, when comparing confrontations between the living E.c. assisi and the control. The experiments were performed at 7.0 p.m. In the labyrinth, the snakes showed in confrontation similar performance to that observed in nature (organizing hunting behaviour, offensive/defensive attack, constriction, prey inspection and feeding behaviour), which were essential to the validity of the experiments and gave behavioural validation within the complex labyrinth.