MYH7-related myopathies: clinical, myopathological and genotypic spectrum in a multicentre French cohort.

BACKGROUND: Myosin heavy chain 7 (MYH7)-related myopathies (MYH7-RMs) are a group of muscle disorders linked to pathogenic variants in the MYH7 gene, encoding the slow/beta-cardiac myosin heavy chain, which is highly expressed in skeletal muscle and heart. The phenotype is heterogeneous including distal, predominantly axial or scapuloperoneal myopathies with variable cardiac involvement. METHODS: We retrospectively analysed the clinical, muscle MRI, genetic and myopathological features of 57 MYH7 patients. Patients received a thorough neurological (n=57, 100%), cardiac (n=51, 89%) and respiratory (n=45, 79%) assessment. Muscle imaging findings and muscle biopsies were reappraised in 19 (33%) and 27 (47%) patients, respectively. RESULTS: We identified three phenotypes with varying degrees of overlap: distal myopathy (70%), scapuloperoneal (23%) and axial with peculiar cervical spine rigidity called the 'sphinx' phenotype (7%). 14% of patients had either dilated cardiomyopathy, hypertrophic cardiomyopathy or left ventricular non-compaction cardiomyopathy. 31% of patients had prominent respiratory involvement, including all patients with the 'sphinx' phenotype. Muscle MRI showed involvement of tibialis anterior, followed by quadriceps, and erector spinae in patients with axial phenotype. Cores represented the most common myopathological lesion. We report 26 pathogenic variants of MYH7 gene, 9 of which are novel. CONCLUSIONS: MYH7-RMs have a large phenotypic spectrum, including distal, scapuloperoneal or axial weakness, and variable cardiac and respiratory involvement. Tibialis anterior is constantly and precociously affected both clinically and on muscle imaging. Cores represent the most common myopathological lesion. Our detailed description of MYH7-RMs should improve their recognition and management.

Macroglossia: A potentially severe complication of late-onset Pompe disease.

BACKGROUND: Pompe disease is a rare neuromuscular disorder caused by a deficiency of a lysosomal enzyme, acid α-glucosidase. Macroglossia is a classic clinical sign of several inherited myopathies and has also been reported to occur progressively in late-onset Pompe disease (LOPD). METHODS: We describe patients with LOPD and macroglossia included in the French national Pompe disease registry. Clinical, functional, and radiological data were collected during periodic follow-up and analyzed retrospectively. These cases were compared with 15 previously reported cases. RESULTS: Five patients, three females and two males, aged 71-88 years, were included in this study. All but one of the patients suffered from symptoms related to macroglossia before the diagnosis of Pompe disease. Three had localized tongue atrophy and one had significant localized tongue hypertrophy which led to glossectomy 10 years before diagnosis. Two patients had severe dysphagia, one of whom underwent gastrostomy for enteral nutritional support. One patient experienced the persistence of numerous sleep apneas despite nocturnal bilevel positive airway pressure (BiPAP) ventilation. All our patients had dysarthria, and two required speech therapy. Four patients had a tongue hypersignal on magnetic resonance imaging (MRI) T1 sequences. CONCLUSIONS: Detection of macroglossia should be part of the clinical diagnosis and follow-up of patients with LOPD, with a careful evaluation of its main consequences. Macroglossia can have severe functional impacts on speech, swallowing, and sleep. Whole-body MRI with facial sections may facilitate the early diagnosis of Pompe disease with the "bright tongue sign".

Myasthenia Gravis Lambert-Eaton overlap syndrome induced by nivolumab in a metastatic melanoma patient.

INTRODUCTION: Myasthenia gravis (MG) Lambert-Eaton (LE) overlap syndrome is a rare condition. Here, we describe the first case of MG-LE overlap syndrome revealed by the anti-programmed cell death 1 inhibitor, nivolumab, in a patient treated for metastatic melanoma. CASE: Three months after receiving nivolumab and 1 month after brain metastasis radiotherapy, our patient developed generalized fatigue with intermittent ptosis and swallowing difficulty suggesting a myasthenic syndrome. Electromyogram findings, anti-acetylcholine receptor, and anti-calcium channel antibodies levels were consistent with an immune-related myasthenic syndrome with specific features for both MG and LE syndromes. Immunotherapy with nivolumab was stopped. Patient was treated with systemic immunosuppressive and anti-cholinesterase drugs, with remarkable improvement of his neurological symptoms. Prolonged partial remission was obtained for his metastatic melanoma without need for a third-line treatment. Two years later, a relapse of hismyasthenic symptoms was observed along with new neurological symptoms related to brain radiation necrosis. CONCLUSION: We describe the first case of MG-LE overlap syndrome diagnosed after anti-PD1 immunotherapy for metastatic melanoma, which appeared after radiation therapy and then relapsed after brain radiation necrosis. We hypothesized a role for brain inflammation as a trigger for MG-LE onset. Neuro-muscular junctions disease induced or revealed by checkpoint inhibitors can be challenging and requires long-term follow-up.

Bent spine syndrome as the initial symptom of late-onset Pompe disease.

INTRODUCTION: Late-onset Pompe disease (LOPD) is a rare disorder characterized by progressive proximal muscle weakness and early respiratory insufficiency, for which enzyme replacement therapy (ERT) is available. METHODS: Having diagnosed a case of LOPD presenting with bent spine syndrome, we conducted a brief survey in the French centers involved in management of Pompe disease, from which we collected data on 3 other cases. RESULTS: The patients (3 women and 1 man) had a mean age of 64 years (range 51-77 years) and a delay in diagnosis of approximately 10 years (range 8-42 years). At diagnosis, 3 patients already had respiratory symptoms. All had normal or very mildly raised creatine kinase levels and magnetic resonance imaging abnormalities in the paraspinal muscles. They exhibited the most frequent mutation in Pompe disease (c.-32-13 T>G). CONCLUSION: Clinicians should be aware of this atypical presentation of LOPD to enable earlier diagnosis and treatment. Muscle Nerve 56: 167-170, 2017.

The various forms of hereditary motor neuron disorders and their historical descriptions.

Motor neuron disorders comprise a clinically and pathologically heterogeneous group of neurologic diseases characterized by progressive degeneration of motor neurons (including both sporadic and hereditary diseases), affecting the upper motor neurons, lower motor neurons, or both. Hereditary motor neuron disorders themselves represent a vast and heterogeneous group, with numerous clinical and genetic overlaps that can be a source of error. This narrative review aims at providing an overview of the main types of inherited motor neuron disorders by recounting the stages in their historical descriptions. For practical purposes, this review of the literature sets out their various clinical characteristics and updates the list of all the genes involved in the various forms of inherited motor neuron disorders, including spinal muscular atrophy, familial amyotrophic lateral sclerosis, hereditary spastic paraplegia, distal hereditary motor neuropathies/neuronopathies, Kennedy's disease, riboflavin transporter deficiencies, VCPopathy and the neurogenic scapuloperoneal syndrome.

Clinical Neurology in Practice: The Tongue (part 2).

BACKGROUND: The tongue is an essential organ for the development of certain crucial functions such as swallowing and speech. The examination of the tongue can be very useful in neurology, as the various types of lingual alterations can lead to certain specific diagnoses, the tongue being a kind of 'mirror' of some neurological function. REVIEW SUMMARY: To discuss the elements of clinical examination of the tongue in relation to neurological disorders. After reviewing the different superficial lesions of the tongue, we deal with various movement disorders of the tongue (fasciculations/myokimia, orolingual tremor, choreic movements of the tongue, dystonia of the tongue, lingual myoclonus, and psychogenic movements), disorders of taste and lingual sensitivity and lingual pain. CONCLUSIONS: Examination of the tongue should not be limited to studying its motility and trophicity. It is equally important to check the sensory function and understand how to interpret abnormal movements involving the tongue. This study also aimed to demonstrate the importance of nonmotor tongue function in neurological practice.

Phenotype variability and natural history of X-linked myopathy with excessive autophagy.

OBJECTIVE: X-linked myopathy with excessive autophagy (XMEA) linked to the VMA21 gene leads to autophagy failure with progressive vacuolation and atrophy of skeletal muscles. Current knowledge of this rare disease is limited. Our objective was to define the clinical, radiological, and natural history of XMEA. METHODS: We conducted a retrospective study collecting clinical, genetic, muscle imaging, and biopsy data of XMEA patients followed in France and reviewed the literature for additional cases. RESULTS: Eighteen males had genetically confirmed XMEA in France, carrying four different VMA21 variants. Mean age at disease onset was 9.4 ± 9.9 (range 1-40) years. In 14/18 patients (77.8%), onset occurred during childhood (< 15 years); however in four patients, the disease started in adulthood. Patients had anterior and medial compartment thigh muscle weakness, distal contractures (56.3%), elevated CK levels (1287.9 ± 757.8 U/l) and autophagic vacuoles with sarcolemmal features on muscle histopathology. Muscle MRI (n = 10) showed a characteristic pattern of lower limb muscle involvement. In 11 patients, outcome measures were available for an average follow-up period of 10.6 ± 9.8 years and six of them show disease progression. Mean change of functional outcomes was 0.5 ± 1.2 points for Brooke and 2.2 ± 2.5 points for Vignos score, 7/16 patients (43.8%) needed a walking aid and 3/16 (18.8%) were wheelchair-bound (median age of 40 years old, range 39-48). The variant c.164-7 T > G was associated with a later onset of symptoms. Respiratory insufficiency was common (57.1%) but cardiac involvement rare (12.5%). INTERPRETATION: XMEA has variable age of onset, but a characteristic clinical, histopathological, and muscle imaging presentation, guiding the diagnosis. Although slowly, motor disability progresses with time, and relevant genotype-phenotype correlations will help design future clinical trials.

Safety of immune checkpoint inhibitor rechallenge after severe immune-related adverse events: a retrospective analysis.

Immune checkpoint inhibitors (ICIs) present clinicians with the challenge of managing immune-related adverse events (irAEs), which can range from mild to severe due to immune system activation 1. While guidelines recommend discontinuing ICIs for grade 3 partial and all grade 4 irAEs, there is growing interest in rechallenging patients based on oncological outcomes, particularly for cardiovascular and neurological irAEs where data remains scarce 1,2. We retrospectively evaluated the safety of ICI rechallenge following grade 3-4 irAEs, specifically focusing on cardiovascular and neurological events, in patients discussed at our multidisciplinary immunotoxicity assessment board between 2019 and 2021. Fifteen patients were included, with a median time to severe irAE onset of 49 days. Among them, five patients experienced neurological adverse events (NAEs): aseptic meningitis (3), inflammatory polyradiculoneuropathy (1), and ophthalmoplegia (1), while one patient presented with myocarditis. Of the 15 patients retreated with ICIs after initial severe irAEs, 11 (73%) remained free of subsequent irAEs, two (13%) experienced recurrence of the initial irAE, and two (13%) developed new irAEs distinct from the initial event. The median time to event recurrence was 69 days, occurring no earlier than the initial severe irAE. In the subset analysis focusing on severe cardiovascular and neurological irAEs, rechallenge with ICIs was generally well tolerated. However, one patient treated with anti-PD1 experienced a relapse of grade 2 aseptic meningitis. Overall, our findings suggest that rechallenging with ICIs after severe irAEs, including those affecting the cardiovascular and neurological systems, may be safe, particularly after irAE regression and corticosteroid withdrawal.

Case report: Parsonage-turner syndrome in a melanoma patient treated by BRAF/MEK inhibitors after immune checkpoint inhibitors.

Introduction: Combination molecular BRAF/MEK inhibitors targeted therapy has been shown to improve overall survival in patients with BRAF V600 mutated unresectable or metastatic melanoma. Most patients treated with BRAF/MEK inhibitors will experience adverse events but neurological adverse events (nAEs) remain rare. Case report: A 42-year-old woman diagnosed with metastatic melanoma presented with an intense pain in the left shoulder 7 days after the beginning of encorafenib/binimetinib after immune checkpoint inhibitors (ICI) combination. No other triggering factors were identified. Electromyogram performed one month after the pain onset revealed a left brachial plexopathy suggestive of a Parsonage-Turner syndrome. The weakness slowly improved with intensive rehabilitation and targeted therapies were continued. Conclusion: We report the first case of Parsonage-Turner syndrome in a melanoma patient treated with encorafenib/binimetinib following checkpoint inhibitors combination.We cannot rule out the implication of ICI in the development of this syndrome but the rapid onset of the symptoms after the beginning of targeted therapies makes their involvment more likely.Given the increased use of BRAF/MEK inhibitors in managing of stage III and IV melanoma, as well as the development in stage II, clinicians should be aware of this potential side effect.

Clinical Neurology in Practice: The Tongue (Part 1).

BACKGROUND: The tongue is an essential organ for the development of certain crucial functions, such as swallowing and language. The examination of the tongue can be very useful in neurology, as the various types of lingual alterations can lead to certain specific diagnoses, the tongue being a kind of "mirror" of some neurological function. REVIEW SUMMARY: In this study, we reviewed the literature on anatomy, physiology, and the various aspects of the examination of the tongue. CONCLUSIONS: Examination of the tongue should be an integral part of the clinical examination of the cranial nerves. This study aimed to demonstrate the importance of tongue motor and non-motor functions in neurological practice.

Brief Communication: Lambert-Eaton Myasthenic Paraneoplastic Syndrome Associated With Merkel Cell Carcinoma Successfully Treated by Immune Checkpoint Inhibitors: 2 Cases.

Merkel cell carcinoma (MCC) is an aggressive neuroendocrine cutaneous tumor with high metastatic potential. In rare cases, it can be associated with paraneoplastic syndromes (PNS), which result from an antitumor immunity against antigens produced by the tumor itself. Lambert-Eaton Myasthenic Syndrome (LEMS) is a neurological autoimmune PNS characterized by an impairment of the neuromuscular junction, leading to proximal muscle weakness and fatigability. Although the development of immune checkpoint inhibitors (ICI) is a breakthrough in the management of many cancers, onset or worsen of immune diseases has been described. Thereby, in patients with previous neurological PNS like LEMS, the ICI therapy for cancer may aggravate neurological symptoms and lead to irreversible impairment. We report here 2 cases of patients with metastatic MCC associated with a LEMS at the diagnosis. Both successfully received ICI therapies (anti-PDL1 avelumab and anti-PD1 pembrolizumab) without worsening of LEMS and any major immune-related adverse effects. Their neurological condition improved and disappeared concomitantly with the efficacy of immunotherapy, and we did not observe relapse of both MCC and LEMS after treatment discontinuation. Finally, we performed a complete review of the literature, which confirmed that ICI treatment could be discussed for patients with paraneoplastic LEMS, and emphasized the need for multidisciplinary management.

In inflammatory myopathies, dropped head/bent spine syndrome is associated with scleromyositis: an international case-control study.

BACKGROUND: Some myopathies can lead to dropped head or bent spine syndrome (DH/BS). The significance of this symptom has not been studied in inflammatory myopathies (IM). OBJECTIVES: To assess the significance of DH/BS in patients with IM. METHODS: Practitioners from five IM networks were invited to report patients with IM suffering from DH/BS (without other known cause than IM). IM patients without DH/BS, randomly selected in each participating centre, were included as controls at a ratio of 2 to 1. RESULTS: 49 DH/BS-IM patients (DH: 57.1%, BS: 42.9%) were compared with 98 control-IM patients. DH/BS-IM patients were older (65 years vs 53 years, p<0.0001) and the diagnosis of IM was delayed (6 months vs 3 months, p=0.009). Weakness prevailing in the upper limbs (42.9% vs 15.3%), dysphagia (57.1% vs 25.5%), muscle atrophy (65.3% vs 34.7%), weight loss (61.2% vs 23.5%) and loss of the ability to walk (24.5% vs 5.1%) were hallmarks of DH/BS-IM (p≤0.0005), for which the patients more frequently received intravenous immunoglobulins (65.3% vs 34.7%, p=0.0004). Moreover, DH/BS-IM patients frequently featured signs and/or complications of systemic sclerosis (SSc), fulfilling the American College of Rheumatology/European Alliance of Associations for Rheumatology criteria for this disease in 40.8% of the cases (vs 5.1%, p<0.0001). Distribution of the myopathy, its severity and its association with SSc were independently associated with DH/BS (p<0.05). Mortality was higher in the DH/BS-IM patients and loss of walking ability was independently associated with survival (p<0.05). CONCLUSION: In IM patients, DH/BS is a marker of severity and is associated with SSc (scleromyositis).

A predictive model of organic acids separation by chromatography with strong anionic resins in sulfate form.

Organic acids commonly have quite symmetrical chromatography profiles at low pH (< 1.5) with strong anionic resins, but a significant tailing can be observed with succinic and citric acids. Classical adsorption models, like the Langmuir model, fail to predict this behavior, which can have a major influence on mean retention times and profile shapes, therefore on chromatography performances. A new retention model was developed to better predict organic acid separation with strong anionic resin. This model combines a refined Langmuir adsorption model and an ion-exchange model. Organic acid adsorption is assumed to be due to hydrogen bonding with sulfate and hydrogen sulfate counter-anions on the resin. The adsorption capacity depends mostly on molecular size: up to sixteen formic acid molecules could be adsorbed per counter-anions, meanwhile only two succinic acid or one citric acid molecules could be adsorbed. This adsorption model was then embedded in a generic and accurate modeling approach (continuous column with mass balance equations solved by the conservation element/solution element (CE/SE) method). All parameters of this column model were identified by fitting the simulation to experimental results (equilibrium curves and pulse tests). Then, the column model was validated with original experimental results from a binary mixture pulse test (formic and succinic acids). Results show that simulations are much more predictive for multi-component pulse tests, both in terms of profile shape and retention time, which cannot be captured without considering ion-exchange.

Usefulness of subcutaneous immunoglobulin therapy in the management of myasthenia gravis: a retrospective cohort study.

INTRODUCTION: To describe the efficacy of subcutaneous immunoglobulin (SCIg) in patients with myasthenia gravis (MG). METHODS: This was a retrospective study conducted in the neuromuscular referral center of Bordeaux (between January 1, 2014 and March 31, 2021) with MG patients treated with SCIg. The main outcome was SCIg efficacy assessed by the before and after SCIg Myasthenia Gravis Foundation of America (MGFA) clinical classification, the duration of hospitalization and the number of days of orotracheal intubation (OTI). RESULTS: Sixteen patients were included in the study (11 females; 5 males). Nine patients were still treated with SCIg at the end of the study (March 31, 2021) and then underwent prospective follow-up. The average age of the patients was 56.1 (19-83) years. The median duration of MG at onset of SCIg was 37.4 months. Eight patients (50%) remained stable (4 in stage MGFA-IV and 4 in MGFA-III). Eight patients (50%) improved: 3 from MGFA-IV to MGFA-III, 1 from MGFA-IV to MGFA-II, 1 from MGFA-IV to MGFA-I, 2 from MGFA-III to MGFA-II and 1 from MGFA-III to MGFA-I (no patient worsened). The duration of disease progression did not appear to affect the response to SCIg therapy. The number of hospital days per month was significantly reduced after SCIg compared to before, and the number of days in intensive care unit and the number of days of OTI were also reduced. Only minor adverse effects were noted, and 80% of patients were in favor of continuing SCIg. CONCLUSIONS: SCIg is a well-tolerated and useful treatment in MG, offering interesting perspectives in the management of MG patients. However, further large-scale prospective studies are needed to confirm these results.

Acute peripheral neuropathy following animal envenomation: A case report and systematic review.

Animal envenomation in humans is usually accidental or for defensive purposes. Depending on the venom composition and administration, different reactions can be observed. After reporting the first case of acute polyradiculitis in a 57-year-old healthy male after red lionfish envenomation, we propose to analyze rare similar cases of acute neuritis after animal envenomation published in the medical literature. Including our case, we found 54 patients who developed acute peripheral neuropathy after having been stung or bitten by various animals, mainly hymenoptera (in half of the cases) but also jellyfishes, snakes, corals or nonhooked arthropods. We observed two distinct patterns of peripheral neuropathy: more than half of them were polyneuropathy while the others were focal neuropathy. The prognosis was favorable in most cases. The pathophysiological mechanism associated with these rare complications remain unknown, although some hypotheses may be proposed. A direct action of certain components of the venom, such as phospholipase-A2, could explain the focal forms of peripheral neuropathy trough toxic reactions and/or vasculitis processes. The more diffuse clinical situations could be due to an allergy-triggered immune-mediated reaction (possibly linked to a molecular mimicry mechanism between venom proteins and some myelin proteins of the peripheral nervous system), or to the action of some venom components on membrane ionic channels particularly at the node of Ranvier. Even if acute peripheral neuropathies are rare after envenomation, they may occur after envenomation from various animals, and their usually favorable prognoses should be known by neurologists.

Neurologic manifestations of giant cell arteritis.

Giant cell arteritis, the most frequent form of vasculitis in persons over 50 years of age, is a granulomatous chronic vasculitis involving large and medium-sized vessels, most commonly the temporal and other cranial arteries. This common, treatable condition is associated with various clinical symptoms, including neurological ones, affecting both the central and peripheral nervous systems. In this review, we discuss the cranial and extra cranial neurological complications of giant cell arteritis, to help avoid the many pitfalls in the diagnosis of giant cell arteritis.

Peripheral neuropathy and livedoid vasculopathy.

BACKGROUND: Livedoid vasculopathy (LV) is a chronic dermatosis associated with micro-thrombosis of the vessels of the dermis, leading to ischemic lesions and painful skin ulcerations of the lower limbs. This thrombosing occlusive vasculopathy, clearly distinct from 'classical vasculitis' (not related to alteration of vessel walls), may lead to peripheral neuropathy. OBJECTIVE: To clarify the main clinical, electrophysiological and pathological characteristics of peripheral neuropathy linked to LV. METHOD: We presented a series of personal cases of peripheral neuropathy due to LV. We also conducted a review of the literature (since the first description of LV in 1974) using multiple combinations of keywords from 'PubMed', 'Google Scholar' and 'ScienceDirect' databases according to the 'Preferred Reporting Items for Systematic reviews and Meta-Analyses' guidelines. RESULTS: We identified 16 patients (6 personal cases and 10 cases from the medical literature). Our personal cases were five females and one male, with a median age (at the onset of cutaneous signs of LV) of 38 (range 25-62). Several types of skin lesions of the lower limbs were observed. Median age at the onset of peripheral neuropathy symptoms was 48 years (range 29-66), with a main clinical and electrophysiological pattern of mononeuropathy multiplex. DISCUSSION: We observed a typical pattern of peripheral neuropathy, mostly mononeuropathy multiplex, whose pathophysiology might be related to occlusions of the small vessels of the nerves, as seen in the dermis. Moreover, LV may also be associated with other types of peripheral neuropathies (sometimes of autoimmune etiology) not directly related to the skin lesions. CONCLUSION: The 'ischemic form' of peripheral neuropathy linked to LV is mainly responsible for sensory disturbances (with multifocal distribution), sometimes for motor disturbances. This type of peripheral neuropathy has to be distinguished from 'classical vasculitic neuropathies' which are usually treated with antithrombotic therapies.

Glial Fibrillary Acidic Protein Autoimmunity: A French Cohort Study.

BACKGROUND AND OBJECTIVES: To report the clinical, biological, and imaging features and clinical course of a French cohort of patients with glial fibrillary acidic protein (GFAP) autoantibodies. METHODS: We retrospectively included all patients who tested positive for GFAP antibodies in the CSF by immunohistochemistry and confirmed by cell-based assay using cells expressing human GFAPα since 2017 from 2 French referral centers. RESULTS: We identified 46 patients with GFAP antibodies. Median age at onset was 43 years, and 65% were men. Infectious prodromal symptoms were found in 82%. Other autoimmune diseases were found in 22% of patients, and coexisting neural autoantibodies in 11%. Tumors were present in 24%, and T-cell dysfunction in 23%. The most frequent presentation was subacute meningoencephalitis (85%), with cerebellar dysfunction in 57% of cases. Other clinical presentations included myelitis (30%) and visual (35%) and peripheral nervous system involvement (24%). MRI showed perivascular radial enhancement in 32%, periventricular T2 hyperintensity in 41%, brainstem involvement in 31%, leptomeningeal enhancement in 26%, and reversible splenial lesions in 4 cases. A total of 33 of 40 patients had a monophasic course, associated with a good outcome at last follow-up (Rankin Score ≤2: 89%), despite a severe clinical presentation. Adult and pediatric features are similar. Thirty-two patients were treated with immunotherapy. A total of 11/22 patients showed negative conversion of GFAP antibodies. DISCUSSION: GFAP autoimmunity is mainly associated with acute/subacute meningoencephalomyelitis with prodromal symptoms, for which tumors and T-cell dysfunction are frequent triggers. The majority of patients followed a monophasic course with a good outcome.