Search

Bromelain is a plant-based molecule with antioxidant, antithrombotic, anticancer, and anti-inflammatory properties. Bromelain has been shown to reduce the release of inflammatory cytokines. This study aimed to determine whether bromelain can prevent ataxia in rats caused by 3-acetylpyridine (3-AP). Thirty-six albino rats were divided into the control, 3-AP, and 3-AP + Brom groups. In the 3-AP + Brom group, bromelain was injected intraperitoneally at 40 mg/kg daily for 30 days. Various techniques such as rotarod, electromyography (EMG), elevated plus maze, IHC, and Sholl analysis were used to evaluate the possible effects of bromelain on cerebellar neurons and glial cells. The results demonstrated significant improvements in most of the 3-AP + Brom, including motor coordination, neuromuscular response, anxiety, oxidative capacity, microgliosis, astrogliosis, cell death, and morphological variables compared to the 3-AP group. The mechanism of action of bromelain in restoring cerebellar ataxia needs further investigation, but it may be a candidate to help restore degeneration in animals with ataxia., Competing Interests: Declaration of competing interest The authors have no conflicts of interest to declare., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Autoimmune cerebellar ataxia (ACA) is a condition characterized by progressive ataxia resulting from an immune-mediated attack on cerebellar structures. The presence of anti-Tr/DNER antibodies, strongly associated with Hodgkin lymphoma, has been identified in ACA. However, cases with no underlying malignancy are rare. We report the case of a 49-year-old woman presenting with progressive ataxia, slurred speech, and dizziness over three months. The patient exhibited significant cerebellar symptoms, including dysarthria and limb ataxia, without signs of other systemic illnesses. Comprehensive investigations, including imaging, lumbar puncture, and autoantibody testing, were performed. The cerebrospinal fluid (CSF) sample revealed positivity for Tr/DNER antibodies, leading to a diagnosis of autoimmune cerebellar ataxia. The patient underwent nine sessions of plasmapheresis, followed by six doses of intravenous immunoglobulin (IVIG), resulting in significant clinical improvement. Despite extensive cancer screening, no underlying malignancy was detected, suggesting a non-tumor origin of anti-Tr/DNER antibodies. The patient's gait improved, ataxia resolved, and cerebellar tests normalized following treatment. The patient was further managed with rituximab treatment every six months. This case represents a presentation of anti-Tr/DNER-associated autoimmune cerebellar ataxia without malignancy. The successful treatment with plasmapheresis and IVIG suggests that these interventions may be effective in managing autoimmune cerebellar ataxia associated with anti-Tr/DNER antibodies. Further research is needed to understand the underlying mechanisms of this condition and to determine the optimal treatment strategies., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Introduction: The last decade has witnessed major breakthroughs in identifying novel genetic causes of hereditary ataxias, deepening our understanding of disease mechanisms, and developing therapies for these debilitating disorders., Areas Covered: This article reviews the currently approved and most promising candidate pharmacotherapies in relation to the known disease mechanisms of the most prevalent autosomal recessive ataxias. Omaveloxolone is an Nrf2 activator that increases antioxidant defense and was recently approved for treatment of Friedreich ataxia. Its therapeutic effect is modest, and further research is needed to find synergistic treatments that would halt or reverse disease progression. Promising approaches include upregulation of frataxin expression by epigenetic mechanisms, direct protein replacement, and gene replacement therapy. For ataxia-telangiectasia, promising approaches include splice-switching antisense oligonucleotides and small molecules targeting oxidative stress, inflammation, and mitochondrial function. Rare recessive ataxias for which disease-modifying therapies exist are also reviewed, emphasizing recently approved therapies. Evidence supporting the use of riluzole and acetyl-leucine in recessive ataxias is discussed., Expert Opinion: Advances in genetic therapies for other neurogenetic conditions have paved the way to implement feasible approaches with potential dramatic benefits. Particularly, as we develop effective treatments for these conditions, we may need to combine therapies, consider newborn testing for pre-symptomatic treatment, and optimize non-pharmacological approaches.

Degenerative cerebellar ataxias comprise a heterogeneous group of rare and ultra-rare genetic diseases. While disease-modifying treatments are now on the horizon for many ataxias, robust trial designs and analysis methods are lacking. To better inform trial designs, we applied item response theory (IRT) modeling to evaluate the natural history progression of several ataxias, assessed with the widely used scale for assessment and rating of ataxia (SARA). A longitudinal IRT model was built utilizing real-world data from the large autosomal recessive cerebellar ataxia (ARCA) registry. Disease progression was evaluated for the overall cohort as well as for the 10 most common ARCA genotypes. Sample sizes were calculated for simulated trials with autosomal recessive spastic ataxia Charlevoix-Saguenay (ARSACS) and polymerase gamma (POLG) ataxia, as showcased, across multiple design and analysis scenarios. Longitudinal IRT models were able to describe the changes in the latent variable underlying SARA as a function of time since ataxia onset for both the overall ARCA cohort and the common genotypes. The typical progression rates varied across genotypes between relatively high in POLG (~ 0.98 SARA points/year at SARA = 20) and very low in COQ8A ataxia (~ 0.003 SARA points/year at SARA = 20). Smaller trial sizes were required in case of faster progression, longer trials (~ 75-90% less with 5 years vs. 2 years), and larger drug effects (~ 70-80% less with 100% vs. 50% inhibition). Simulating under the developed IRT model, the longitudinal IRT model had the highest power, with a well-controlled type I error, compared to total score models or end-of-treatment analyses. The established longitudinal IRT framework allows efficient utilization of natural history data and ultimately facilitates the design and analysis of treatment trials in rare and ultra-rare genetic ataxias., (© 2024 The Author(s). Clinical Pharmacology & Therapeutics published by Wiley Periodicals LLC on behalf of American Society for Clinical Pharmacology and Therapeutics.)

Cerebellar ataxia is a heterogeneous group of neural disorders clinically characterized by cerebellar dysfunction. The diagnosis of patients with progressive cerebellar ataxia is complex due to the direct correlation with other neuron diseases. Although there is still no cure for this pathological condition, some metabolic, hereditary, inflammatory, and immunological factors affecting cerebellar ataxia are being studied and may become therapeutic targets. Advances in studying the neuroanatomy, pathophysiology, and molecular biology of the cerebellum (CE) contribute to a better understanding of the mechanisms behind the development of this disorder. In this study, Wistar rats aged 30 to 35 days were injected intraperitoneally with 3-acetylpyridine (3-AP) and/or metformin (for AMP-activated protein kinase (AMPK) enzyme activation) and euthanized in 24 hours and 4 days after injection. We analyzed the neuromodulatory role of the AMPK on cerebellar ataxia induced by the neurotoxin 3-AP in the brain stem (BS) and CE, after pre-treatment for 7 and 15 days with metformin, a pharmacological indirect activator of AMPK. The results shown here suggest that AMPK activation in the BS and CE leads to a significant reduction in neuroinflammation in these regions. AMPK was able to restore the changes in fatty acid composition and pro-inflammatory cytokines caused by 3-AP, suggesting that the action of AMPK seems to result in a possible neuroprotection on the cerebellar ataxia model., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

With disease-modifying drugs on the horizon for degenerative ataxias, ecologically valid, finely granulated, digital health measures are highly warranted to augment clinical and patient-reported outcome measures. Gait and balance disturbances most often present as the first signs of degenerative cerebellar ataxia and are the most reported disabling features in disease progression. Thus, digital gait and balance measures constitute promising and relevant performance outcomes for clinical trials.This narrative review with embedded consensus will describe evidence for the sensitivity of digital gait and balance measures for evaluating ataxia severity and progression, propose a consensus protocol for establishing gait and balance metrics in natural history studies and clinical trials, and discuss relevant issues for their use as performance outcomes., (© 2023. The Author(s).)

Anti-DNER antibody is associated with paraneoplastic cerebellar degeneration (PCD) and Hodgkin's disease (HD). However, recent studies reported cases absence of HD and that non-tumor anti-DNER antibody-associated ataxia was not well characterized. We present a case of acute cerebellar ataxia and nystagmus with detected anti-DNER antibody. Brain magnetic resonance imaging (MRI) showed cerebellar atrophy. High titer of anti-DNER antibody was detected in CSF and serum. Positron emission tomography (PET) scanning was unremarkable at a 10-month follow up. The patient improved significantly after immunosuppressive therapy with intravenous steroids, immunoglobulin followed by rituximab. Our study suggest that the presence of such anti-neuronal antibodies might not come along with malignancy and that early onset non-tumor patients are more likely to have a better outcome after immunotherapy. Early diagnosis and timely immunosuppressive therapy may prove beneficial for these patients., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Aim: Disruption in cerebellar inputs, as well as dysfunction of Purkinje cells (PCs), causes a change in the timing of electrical signaling in the cerebellum resulting in disorders such as cerebellar ataxia. Although much clinical and molecular genetics research has been conducted to understand this disorder, there is no specific treatment for cerebellar ataxia. As cannabinoid type 1 receptors (CB1Rs) are highly expressed in the cerebellum and have been suggested as a therapeutic strategy, we determined whether AM251, a cannabinoid receptor antagonist, was neuroprotective of PCs in a rat cerebellar ataxic model. Materials and methods: To this end, we conducted behavioral and histological tests in the 3-acetylpyridine (3AP) rat cerebellar ataxia model, to explore whether AM251 was protective against induction of ataxia and cell death. Results : Rats with chemical degeneration of the inferior olive induced by 3AP (55 mg/kg, i.p.) clearly showed cerebellar ataxic symptoms. The locomotor activity and motor coordination of the ataxic animals were clearly disrupted compared to the control group. Further, histological analysis showed cell death and PCs degenerated with loss of cell membrane integrity associated with 3AP. Pre-treatment by AM251 improved the locomotor activity of the ataxic animals, and AM251 almost prevented PCs neuronal degeneration. Conclusion: Our data which show protection of cerebellar PCs and motor improvement in the ataxic rat model by treatment with AM251 suggests that targeting cannabinoid receptors should be considered for therapeutic intervention in cerebellar ataxia.HIGHLIGHTS:AM251 was protective against induction of ataxia and cell death.CBR antagonist typically ameliorated 3AP induced Ataxia.AM251 affected explorative and gait disturbances induced by 3AP.CBR antagonist improved impairments of anxiety-like behaviors following 3AP.

We report two novel cases of autoimmune cerebellar ataxia (ACA) associated with anti-glutamate receptor δ2 antibodies (Gluδ2-Abs). The first case was confirmed by indirect immunofluorescence and cell-based assays: a 29-year-old woman presented after 5 days of headache and vomiting, a pancerebellar syndrome, downbeat nystagmus, decreased visual acuity linked to bilateral retrobulbar optic neuritis (RON), and lymphocytic pleocytosis in the cerebrospinal fluid (CSF) without any abnormality detected using cerebral magnetic resonance imaging (MRI). Second-line immunotherapy allowed progressive clinical improvement, with full recovery achieved after a 4-year follow-up. Thereafter, we retrospectively tested Gluδ2-Abs in 350 patients with a suspicion of autoimmune encephalitis without characterized autoantibody. We identified a second case, a 12-year-old boy who developed 10 days after a respiratory infection, a static cerebellar syndrome with lymphocytosis in the CSF, and right cerebellum hyperintensity in MRI. Five days of corticosteroid treatment allowed a quick clinical improvement. No tumor was identified in both cases, whereas laboratory analyses revealed autoimmune stigma. The present cases suggested that ACA associated with Gluδ2-Abs is an extremely rare but treatable disease. Therefore, testing for Gluδ2-Abs might be considered in the setting of suspected ACA and no initial antibody identification. The visual deficits and ocular motility abnormalities observed in the first reported case might be part of the clinical spectrum of Gluδ2-Abs ACA. Young age, infectious prodromes, lymphocytic pleocytosis, and autoimmune background usually appear together with this syndrome and should lead to discuss the initiation of immunotherapy (after ruling out differential diagnosis, especially infectious causes)., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Multiple system atrophy (MSA) is a neurodegenerative disorder characterized by autonomic failure and motor dysfunction in parkinsonism and/or cerebellar ataxia. Patients with MSA usually present with depression and anxiety symptoms. This observational study of patients with MSA-cerebellar subtype (MSA-C) with subthreshold depression/anxiety symptoms aimed to compare the efficacy of escitalopram oxalate (an antidepressant drug) and tandospirone citrate (an anxiolytic drug)., Methods: Fifty-six MSA-C patients were included, with 28 patients in each treatment group. One group received escitalopram oxalate 10 mg/day and the other group received tandospirone citrate 30 mg/day. The patients were evaluated at baseline and after 4 weeks. Several psychiatric and neurological tests were performed, including the Hamilton Anxiety Rating Scale (HAMA), Hamilton Depression Rating Scale (HAMD), Scale for the Assessment and Rating of Ataxia (SARA), and the Scale for Outcomes in Parkinson's Disease for Autonomic Symptoms (SCOPA-AUT). Furthermore, post-void residual urine volume (PVR) and blood pressure were measured., Results: There was a more substantial reduction in the HAMA/HAMD, scores of stance, finger tracking, and finger nose test in the SARA, and PVR in the tandospirone group. There was a more substantial reduction in scores of dysuria, light-headed when standing up, syncope and hyperhidrosis in the SCOPA-AUT in the escitalopram group (p's < 0.05)., Conclusions: Tandospirone citrate was more effective in improving depression/anxiety and some cerebellar ataxia symptoms, whereas escitalopram was more effective in improving some autonomic symptoms in MSA-C patients over a short-term period in an open-label observational study without a control group. Further research is needed to evaluate the long-term effects of tandospirone and escitalopram in MSA-C in long-term placebo controlled trials., Competing Interests: Declaration of competing interest None., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Primary autoimmune cerebellar ataxia (PACA) is an idiopathic sporadic cerebellar ataxia that is thought to be immune-mediated but lacks biomarkers or a known cause. Here, we report two cases of immune-mediated cerebellar ataxia that responded favorably to immunotherapy, in which tissue-based indirect immunofluorescence test for serum or cerebrospinal fluid (CSF) samples yielded positive results. Case 1 was a 78-year-old man who presented with subacute progressive gait ataxia with truncal instability and dysarthria in response to steroids. Case 2 was a 62-year-old man who presented with relapses and remissions of acute progressive cerebellar ataxia occurring 1-2 times per year. Despite a favorable response to steroid treatment, he relapsed repeatedly in the absence of long-term immunosuppression. In the case of "idiopathic" cerebellar ataxia, immune-mediated causes should be investigated, and immunotherapy may have therapeutic effects., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Multiple Sulfatase Deficiency (MSD) is a rare autosomal recessive disease with specific clinical findings such as psychomotor retardation and neurological deterioration. No therapy is available for this genetic disorder. Previous studies have shown that N-acetyl-L-leucine (NALL) can improve the neurological inflammation in the cerebellum.In the current study, the effects of NALL on ataxia symptoms and quality of life were explored in a patient with MSD.This study was a crossover case study. The subject, a girl aged 12 years old, received NALL at a dose of 3 g/day (1 g in the morning, 1 g in the afternoon, and 1 g in the evening). A fasting blood sample was taken from the subject to evaluate side effects before the intervention and 4 weeks after taking supplement/placebo in every study stage. The ataxia moving symptoms were evaluated using the Scale for the Assessment and Rating of Ataxia (SARA) score in every study stage. Dietary intake was measured using 24-h dietary recall before and after the intervention. The diet compositions were assessed by Nutritionist IV software. Serum IL-6 level was measured using an ELISA kit.There was no significant change in complete blood count (CBC) and serum biochemical factors in the patient with MSD after receiving NALL (3 g/day) over 4 weeks. The SARA score was reduced by 25%. The gait whose maximum score accounts for approximately one-fifth of the maximum total SARA score (8/40) was decreased. The heel-to-shin slide, the only SARA item performed without visual control, was also improved after therapy. Furthermore, there was a downward trend in the 8MWT (8.71 to 7.93 s). Regarding quality of life assessments, the parent and child reported improved quality of life index, physical health, and emotional function after taking NALL. Moreover, total energy intake was increased with NALL treatment through the study period.Supplementation with NALL at a dose of 3 g/day over 4 weeks was well tolerated and improved ataxia symptoms, quality of life measure, and serum IL-6 levels in the patient with MSD. Further proof-of-concept trials are warranted to confirm the present findings., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

COQ8A-ataxia is a rare form of neurodegenerative disorder due to mutations in the COQ8A gene. The encoded mitochondrial protein is involved in the regulation of coenzyme Q10 biosynthesis. Previous studies on the constitutive Coq8a-/- mice indicated specific alterations of cerebellar Purkinje neurons involving altered electrophysiological function and dark cell degeneration. In the present manuscript, we extend our understanding of the contribution of Purkinje neuron dysfunction to the pathology. By generating a Purkinje-specific conditional COQ8A knockout, we demonstrate that loss of COQ8A in Purkinje neurons is the main cause of cerebellar ataxia. Furthermore, through in vivo and in vitro approaches, we show that COQ8A-depleted Purkinje neurons have abnormal dendritic arborizations, altered mitochondria function and intracellular calcium dysregulation. Furthermore, we demonstrate that oxidative phosphorylation, in particular Complex IV, is primarily altered at presymptomatic stages of the disease. Finally, the morphology of primary Purkinje neurons as well as the mitochondrial dysfunction and calcium dysregulation could be rescued by CoQ10 treatment, suggesting that CoQ10 could be a beneficial treatment for COQ8A-ataxia., (© The Author(s) 2023. Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Introduction: Cerebellar ataxias (CAs) represent neurological disorders with multiple etiologies and a high phenotypic variability. Despite progress in the understanding of pathogenesis, few therapies are available so far. Closing the loop between preclinical studies and therapeutic trials is important, given the impact of CAs upon patients' health and the roles of the cerebellum in multiple domains. Because of a rapid advance in research on CAs, it is necessary to summarize the main findings and discuss future directions., Areas Covered: We focus our discussion on preclinical models, cerebellar reserve, the therapeutic management of CAs, and suitable surrogate markers. We searched Web of Science and PubMed using keywords relevant to cerebellar diseases, therapy, and preclinical models., Expert Opinion: There are many symptomatic and/or disease-modifying therapeutic approaches under investigation. For therapy development, preclinical studies, standardization of disease evaluation, safety assessment, and demonstration of clinical improvements are essential. Stage of the disease and the level of the cerebellar reserve determine the goals of the therapy. Deficits in multiple categories and heterogeneity of CAs may require disease-, stage-, and symptom-specific therapies. More research is needed to clarify how therapies targeting the cerebellum influence both basal ganglia and the cerebral cortex, poorly explored domains in CAs.

Cerebellar ataxia (CA) related to anti-metabolic glutamate receptor 1 (mGluR1) is a rare autoimmune encephalitis, which is manifested as acute or subacute CA in most cases.To the best of our knowledge, only three cases of pediatric patients have been reported in the literature so far. This article reports the 4th case of mGluR1 related CA in a pediatric patient., Competing Interests: Declaration of Competing Interest The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

Cerebellar ataxia is a neurodegenerative disorder with no definitive treatment. Although previous study demonstrated the neuroprotective effects of Hericium erinaceus ( H.E. ), the mechanisms of H.E . treatment on the neuroinflammatory response, neurotransmission, and related metabolites remain largely unknown. We demonstrated that 3-AP rats treated with 25 mg/kg H.E. extracts had improved motor coordination and balance in the accelerated rotarod and rod tests. We showed that the H.E . treatment upregulated the expression of Tgfb1, Tgfb2, and Smad3 genes to levels comparable to those in the non-3-AP control group. Interestingly, we also observed a significant correlation between Tgfb2 gene expression and rod test performance in the 3-AP saline group, but not in the non-3-AP control or H.E .+3-AP groups, indicating a relationship between Tgfb2 gene expression and motor balance in the 3-AP rat model. Additionally, we also found that the H.E . treatment increased mitochondrial COX-IV protein expression and normalized dopamine-serotonin neurotransmission and metabolite levels in the cerebellum of the H.E .+3-AP group compared to the 3-AP saline group. In conclusion, our findings suggest that the H.E . treatment improved motor function in the 3-AP rat model, which was potentially mediated through neuroprotective mechanisms involving TGFB2-Smad3 signaling via normalization of neurotransmission and metabolic pathways.

Background: Antibodies against glutamic acid decarboxylase (GAD-abs) at high serum levels are associated with diverse autoimmune neurological syndromes (AINS), including cerebellar ataxia, epilepsy, limbic encephalitis and stiff-person syndrome. The impact of low serum GAD-ab levels in patients with suspected AINS remains controversial. Specific intrathecal GAD-ab synthesis may serve as a marker for GAD-ab-associated nervous system autoimmunity. We present characteristics of a multicentric patient cohort with suspected AINS associated with GAD antibodies (SAINS-GAD+) and explore the relevance of serum GAD-ab levels and intrathecal GAD-ab synthesis., Methods: All patients with SAINS-GAD+ included in the registry of the German Network for Research on Autoimmune Encephalitis (GENERATE) from 2011 to 2019 were analyzed. High serum GAD-ab levels were defined as RIA>2000 U/mL, ELISA>1000 U/mL, or as a positive staining pattern on cell-based assays., Results: One-hundred-one patients were analyzed. In descending order they presented with epilepsy/limbic encephalitis (39%), cerebellar ataxia (28%), stiff person syndrome (22%), and overlap syndrome (12%). Immunotherapy was administered in 89% of cases with improvements in 46%. 35% of SAINS-GAD+ patients had low GAD-ab serum levels. Notably, unmatched oligoclonal bands in CSF but not in serum were more frequent in patients with low GAD-ab serum levels. GAD-ab-levels (high/low) and intrathecal GAD-ab synthesis (present or not) did not impact clinical characteristics and outcome., Conclusions: Overall, immunotherapy in SAINS-GAD+ was moderately effective. Serum GAD-ab levels and the absence or presence of intrathecal GAD-ab synthesis did not predict clinical characteristics or outcomes in SAINS-GAD+. The detection of unmatched oligoclonal bands might outweigh low GAD-ab serum levels., Competing Interests: Declaration of Competing Interest Madlener, Doppler, Finke, Gerner, Lewerenz, Linsa, Mues, Paliantonis, Priller, Prüß, Rössling, Schirotzek, Senel, Sommer, Strippel, Süße, Tauber, Wandinger, Wickel: Nothing to report. Fink: Bayer, Desitin, GSK, Novartis, Pfizer: lectures. Kellingshaus: UCB Pharma, Eisai GmbH, LivaNova Europe: lectures, consultancies. Kraft: Böhringer-Ingelheim, Daichii-Sankyo, Pfitzer/BMS, Bayer: travel expenses, lectures. Kümpfel: Bayer Healthcare, Merck, Novartis Pharma, Roche Pharma: lectures, consultancies. Leypoldt: Alexion, Roche and Biogen AdvisoryBoard, Novartis, Bayer, Roche: lectures. Malter: UCB Pharma, EISAI GmbH: lectures, consultancies. Melzer: Biogen Idec, GlaxoSmith Kline, Teva, Novartis Pharma, Bayer Healthcare, Genzyme, Alexion Pharamceuticals, Fresenius Medical Care, Diamed, and BIAL: lectures, Euroimmun, Fresenius Medical Care, Diamed, Alexion Pharamceuticals, and Novartis Pharma: funding. Menge: Biogen, Novartis, Teva: lectures, Biogen: consultancies, travel expenses. Ringelstein: Novartis, Bayer, Roche, Alexion, Ipsen: lectures, Bayer Schering, Biogen Idec, Merz, Genzyme, Teva, Grifols, Roche and Merck: travel expenses. Urbanek: Böhringer-Ingelheim: lectures, Daichii-Sankyo: lectures, travel expenses, sPfitzer/BMS: travel expenses. Senel: Bayer, Biogen, Merck, Roche, and Sanofi Genzyme: lectures and/or consultancies; Celgene, TEVA: travel expenses. Sühs: Merck: lectures, travel expenses. Tauber: Teva, Biogen, Merck Serono und Roche: lectures, travel expenses. Thaler: Novartis: funding. Then Bergh: Actelion, Novartis: funding; Actelion, Bayer, Merck, Roche: lectures; Merck, Roche, Sanofi-Genzyme: Advisory Board; Actelion, Merck: travel expenses., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Ataxia-telangiectasia (AT) is a rare autosomal recessive disorder with no available curative treatment. Although the positive effects of N-acetyl-DL-leucine on cerebellar ataxia have been reported previously, there is little evidence of N-acetyl-DL-leucine's effects in patients with AT. This study assessed the effect of 16 weeks N-acetyl-DL-leucine supplementation on ataxia symptoms in a 9-year-old female with AT. The subject consumed 4 g/day N-acetyl-DL-leucine (2 g in the morning and 2 g in the evening) for 16 weeks. Safety was assessed via clinical blood chemistry prior to the intervention and after 6 and 16 weeks. Additionally, The Scale for the Assessment and Rating of Ataxia (SARA) score was used to assess the drug's effects on ataxia symptoms at baseline, 6, 12, and 16 weeks. Quality of life has also been evaluated by a specialist using the PedsQL questionnaire.Despite some initial (first week only) nausea and constipation, supplementation with N-acetyl-DL-leucine was well tolerated and safe according to blood chemistry measures. The SARA score progressively improved, and by week 16 had improved by 11.0 points (48.88%). Parent and self-reported quality of life assessments indicated physical, emotional, social, and school functions all improved by 16 weeks. Supplementation with N-acetyl-DL-leucine at a dose of 4 g/day for 16 weeks was well tolerated and significantly improved ataxia symptoms and quality of life measures in a young child with AT., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

In the last decade, variants in the Ca 2+ channel gene CACNA1A emerged as a frequent aetiology of rare neurological phenotypes sharing a common denominator of variable paroxysmal manifestations and chronic cerebellar dysfunction. The spectrum of paroxysmal manifestations encompasses migraine with hemiplegic aura, episodic ataxia, epilepsy and paroxysmal non-epileptic movement disorders. Additional chronic neurological symptoms range from severe developmental phenotypes in early-onset cases to neurobehavioural disorders and chronic cerebellar ataxia in older children and adults.In the present review we systematically approach the clinical manifestations of CACNA1A variants, delineate genotype-phenotype correlations and elaborate on the emerging concept of an age-dependent phenotypic spectrum in CACNA1A disease. We furthermore reflect on different therapy options available for paroxysmal symptoms in CACNA1A and address open issues to prioritize in the future clinical research., (© 2023. The Author(s), under exclusive license to Springer Nature Switzerland AG.)

Background: Cerebellar ataxia (CA) is a form of ataxia that adversely affects the cerebellum. This study aims to investigate the therapeutic effects of melittin (MEL) on a 3-acetylpyridine-induced (3-AP) cerebellar ataxia (CA) rat model., Methods: Initially, CA rat models were generated by 3-AP administration followed by the subcutaneous injection of MEL. The open-field test was used for the evaluation of locomotion and anxiety. Immunohistochemistry was also conducted for the autophagy markers of LC3 and Beclin1. In the next step, the morphology of the astrocyte, the cell responsible for maintaining homeostasis in the CNS, was evaluated by the Sholl analysis., Results: The findings suggested that the administration of MEL in a 3-AP model of ataxia improved locomotion and anxiety (P < 0.001), decreased the expression of LC3 (P < 0.01) and Beclin1 (P < 0.05), increased astrocyte complexity (P < 0.05) and reduced astrocyte cell soma size (P < 0.001)., Conclusions: Overall, the findings imply that the MEL attenuates the 3-AP-induced autophagy, causes cell death and improves motor function. As such, it could be used as a therapeutic procedure for CA due to its neuroprotective effects., Competing Interests: Declaration of Competing Interest The authors declare that they have no conflict of interest., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Cerebellar ataxia is a neurodegenerative disorder leading to severe motor incoordination. Recently, it has been suggested that cannabinoids play a role in modulating ataxic symptoms. To understand the possible therapeutic effect of cannabinoids for the management of cerebellar ataxia, we used cannabinoid agonist/antagonists to target the cannabinoid type 1 receptor (CB1R) in the 3 acetyl pyridine (3AP) rat model of ataxia. The role of the CB1R was examined using three different doses of the CB1R agonist, WIN-55,212-2 (WIN; 0.1, 0.5, 1 mg/kg) administrated 30 min prior to 3AP (55 mg/kg, i.p.) which leads to motor impairment through destruction of the inferior olive. In some groups, the CB1R antagonist AM251 (1 mg/kg) was given in combination with WIN. Locomotor activity and motor coordination were impaired by 3AP, and the application of WIN did not ameliorate this effect. However, the abnormal gait, rearing and grooming caused by 3AP were prevented by co-administration of AM251 with WIN. While the addition of the CB1R antagonist improved some ataxic symptoms, there was no effect of AM251 on balance or locomotor activity when co-administrated with WIN. Behavioral testing indicated that not only did WIN fail to exert any protective effect on ataxic symptoms; it exacerbated ataxic symptoms, suggesting that CB1R agonists may not be the ideal therapeutic drug in this disorder. When taken together, the findings from the present study indicate that cannabinoid modulation of ataxia symptoms may not act solely through CB1Rs and other cannabinoid receptors should be considered in future studies., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Impaired cerebellar Purkinje neuron firing resulting from reduced expression of large-conductance calcium-activated potassium (BK) channels is a consistent feature in models of inherited neurodegenerative spinocerebellar ataxia (SCA). Restoring BK channel expression improves motor function and delays cerebellar degeneration, indicating that BK channels are an attractive therapeutic target. Current BK channel activators lack specificity and potency and are therefore poor templates for future drug development. We implemented an automated patch clamp platform for high-throughput drug discovery of BK channel activators using the Nanion SyncroPatch 384PE system. We screened over 15,000 compounds for their ability to increase BK channel current amplitude under conditions of lower intracellular calcium that is present in disease. We identified several novel BK channel activators that were then retested on the SyncroPatch 384PE to generate concentration-response curves (CRCs). Compounds with favorable CRCs were subsequently tested for their ability to improve irregular cerebellar Purkinje neuron spiking, characteristic of BK channel dysfunction in SCA1 mice. We identified a novel BK channel activator, 4-chloro- N -(5-chloro-2-cyanophenyl)-3-(trifluoromethyl)benzene-1-sulfonamide (herein renamed BK-20), that exhibited a more potent half-maximal activation of BK current (pAC50 = 4.64) than NS-1619 (pAC50 = 3.7) at a free internal calcium concentration of 270 nM in a heterologous expression system and improved spiking regularity in SCA1 Purkinje neurons. BK-20 had no activity on small-conductance calcium-activated potassium (SK)1-3 channels but interestingly was a potent blocker of the T-type calcium channel, Cav3.1 (IC 50 = 1.05 μ M). Our work describes both a novel compound for further drug development in disorders with irregular Purkinje spiking and a unique platform for drug discovery in degenerative ataxias. SIGNIFICANCE STATEMENT: Motor impairment associated with altered Purkinje cell spiking due to dysregulation of large-conductance calcium-activated potassium (BK) channel expression and function is a shared feature of disease in many degenerative ataxias. BK channel activators represent an outstanding therapeutic agent for ataxia. We have developed a high-throughput platform to screen for BK channel activators and identified a novel compound that can serve as a template for future drug development for the treatment of these disabling disorders., (Copyright © 2022 by The American Society for Pharmacology and Experimental Therapeutics.)

Introduction: The antiseizure medication phenytoin has been associated with changes in the cerebellum, cerebellar signs, and permanent cerebellar damage. We have systematically reviewed the clinical and radiological features, and their correlation., Areas Covered: We identified sixty case reports and case series of the effects of phenytoin on the cerebellum by searching Medline and Embase and relevant reference lists. The reports described 92 [median 1, range 1-5] cases, documented median age 28 [2.7-78] years. Eighty-one cases described one or more clinical sign of ataxia (present in 96%), dysarthria (63%), and nystagmus (70%). The neurological outcome (in 76 cases): 10 (13%) recovered by 12 months; 55 (72%) suffered residual disability; and 11 (14%) died. Median serum phenytoin concentration (48 cases) was 50 (interquartile range 31-66) mg/L; only three values were below 20 mg/L. The radiological findings included cerebellar atrophy in 41 of 61 patients (67%) with at least one scan., Expert Opinion: Evidence mainly comes from case reports, and is inevitably biased. Most patients with cerebellar dysfunction have phenytoin concentrations above the reference range. Clinical signs of ataxia can persist without radiological evidence of cerebellar atrophy, and cerebellar atrophy is seen without any clinical evidence of cerebellar dysfunction.

Introduction: Primary coenzyme Q10 (CoQ10) deficiency, a recessive disorder associated with various defects of CoQ10 biosynthesis and widely varying clinical presentation, is customarily managed by oral Q10 supplementation but the benefit is debated., Methods: To address this question, we mapped individual responses in two patients with COQ8A-related ataxia following coenzyme Q10 supplementation using noninvasive imaging. Metabolic 31 phosphorus magnetic resonance spectroscopy imaging ( 31 P-MRSI) and volumetric cerebellar neuroimaging were performed to quantify the individual treatment response in two patients with COQ8A-related ataxia, each compared with eight age- and gender-matched healthy control subjects., Results: Post-treatment change in energy metabolite levels differed in the two patients, with higher energy levels and improved dysarthria and leg coordination in one, and decreased energy levels without clinical benefit in the other., Conclusions: Our results suggest that the cerebellar bioenergetic state may predict treatment response in COQ8A-related ataxia and highlight the potential of pathophysiology-orientated neuroimaging evidence to inform treatment decisions., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Cerebellar ataxia (CA) is a condition in which cerebellar dysfunction leads to movement disorders such as dysmetria, asynergy and dysdiadochokinesia. This study investigates the therapeutic effects of Melittin (MEL) on 3-acetylpyridine-induced (3-AP) cerebellar ataxia (CA) rat model. Initially, CA rat models were generated by 3-AP administration followed by the intraperitoneal injection of MEL. Then, motor performance and electromyography (EMG) activity were assessed. Afterwards, the pro-inflammatory cytokines were analyzed in the cerebellar tissue. Moreover, the anti-apoptotic role of MEL in CA and its relationship with the protection of Purkinje cells were explored. The findings showed that the administration of MEL in a 3-AP model of ataxia improved motor coordination (P < 0.001) and neuro-muscular activity (p < 0.05), prevented the cerebellar volume loss (P < 0.01), reduced the level of inflammatory cytokines (p < 0.05) and thwarted the degeneration of Purkinje cells against 3-AP toxicity (P < 0.001). Overall, the findings imply that the MEL attenuates the 3-AP-induced inflammatory response. As such, it could be used as a treatment option for CA due to its anti-inflammatory effects., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Objectives: Seizure-related 6 homolog like 2 (SEZ6L2) antibody-associated ataxia is an extremely rare disease. Six patients have been reported and none of them improved significantly with immunotherapy. Herein, we present the case of a patient with cerebellar ataxia and SEZ6L2 antibodies who benefited from immunotherapy, which dramatically altered the course of her disease., Methods: We present a case report of a 73-year-old woman with progressive balance problems. Her condition had rapidly deteriorated in the 2 weeks before the admission to our hospital leading to repeated falls and eventually left her bed-ridden., Results: She presented with severe trunk ataxia, bidirectional nystagmus, dysarthric speech, and persistent nausea. With the exception of cerebellar atrophy, extensive imaging studies revealed no pathology. SEZ6L2 antibodies were found in both CSF and serum. Over a period of 9 months, our patient received immunotherapy consisting of steroid pulse therapy, IV immunoglobulin infusions, rituximab, and cyclophosphamide. Consequently, her condition improved markedly, and she was discharged home from the neurologic rehabilitation unit., Discussion: Our case report shows that intense sequential immunotherapy may considerably improve level of functioning in some patients with SEZ6L2 antibody-associated cerebellar ataxia., Classification of Evidence: This provides Class IV evidence. It is a single observational study without controls., (Copyright © 2022 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.)

Placebo response in degenerative cerebellar ataxias (CAs) has never been studied despite the large number of randomized controlled trials (RCTs) that have been conducted. In this descriptive review, we aimed to examine the placebo response in patients with CAs. We performed a literature search on PubMed for RCTs on CAs that were published from 1977 to January 2020 and collected data on the changes from the baseline to the endpoint on various objective ataxia-associated clinical rating scales. We reviewed 56 clinical trials, finally including 35 parallel-group studies and excluding 21 cross-over studies. The included studies were categorized as follows: (1) studies showing significant improvements in one or more ataxia scales in the placebo groups (n = 3); (2) studies reporting individual placebo responders with improvements in one or more ataxia scales in the placebo groups (n = 5)-the overall proportion of placebo responders was 31.9%; (3) studies showing mean changes in the direction of improvement in at least one ataxia scale in the placebo groups, though not statistically significant (n = 19); (4) studies showing no placebo response in any of the ataxia scales in the placebo groups (n = 4); (5) studies where data on the placebo groups were unavailable (n = 9). This review demonstrated the placebo response in patients with CAs on various objective ataxia scales. Our study emphasizes that the placebo response should be considered when designing, analyzing, and interpreting clinical trials and in clinical practice in CA patients., (© 2020. Springer-Verlag GmbH Germany, part of Springer Nature.)

Rationale: Familial hemiplegic migraine (FHM) is a rare, autosomal dominant migraine with aura. CACNA1A encodes the α1A subunit of P/Q-type voltage-gated calcium channels, and its mutations have been associated with a wide spectrum of episodic and chronic neurological disorders, including FHM type 1 (FHM1)., Patient Concerns: A Chinese girl and some of her relatives who presented with hemiplegia with or without migraine were found to carry a novel heterozygous missense variant, I1379F, in CACNA1A by whole-exome sequencing. The variant consegregated with the disease and was predicted to be pathogenic., Diagnosis: The patient was diagnosed with FHM1 clinically and genetically., Interventions: Prophylactic therapy with flunarizine 5 mg daily was prescribed to the patient., Outcomes: Therapy with flunarizine was terminated after a few weeks. The intensity of the attacks was the same as before., Lessons: This case indicates that FHM should be considered when a patient manifests with episodic hemiplegia without migraine. In addition, genetic testing is an indispensable method to identify atypical attacks of hemiplegic migraine., Competing Interests: The authors have no conflicts of interests to disclose., (Copyright © 2021 the Author(s). Published by Wolters Kluwer Health, Inc.)

Importance: Cerebellar ataxia is a neurodegenerative disease impairing motor function characterized by ataxia of stance, gait, speech, and fine motor disturbances., Objective: To investigate the efficacy, safety, and tolerability of the modified essential amino acid acetyl-DL-leucine in treating patients who have cerebellar ataxia., Design, Setting, and Participants: The Acetyl-DL-leucine on Cerebellar Ataxia (ALCAT) trial was an investigator-initiated, multicenter, double-blind, randomized, placebo-controlled, clinical crossover trial. The study was conducted at 7 university hospitals in Germany and Austria between January 25, 2016, and February 17, 2017. Patients were aged at least 18 years and diagnosed with cerebellar ataxia of hereditary (suspected or genetically confirmed) or nonhereditary or unknown type presenting with a total score of at least 3 points on the Scale for the Assessment and Rating of Ataxia (SARA). Statistical analysis was performed from April 2018 to June 2018 and January 2020 to March 2020., Interventions: Patients were randomly assigned (1:1) to receive acetyl-DL-leucine orally (5 g per day after 2 weeks up-titration) followed by a matched placebo, each for 6 weeks, separated by a 4-week washout, or vice versa. The randomization was done via a web-based, permuted block-wise randomization list (block size, 2) that was stratified by disease subtype (hereditary vs nonhereditary or unknown) and site., Main Outcomes and Measures: Primary efficacy outcome was the absolute change of SARA total score from (period-dependent) baseline to week 6., Results: Among 108 patients who were randomly assigned to sequence groups (54 patients each), 55 (50.9%) were female; the mean (SD) age was 54.8 (14.4) years; and the mean (SD) SARA total score was 13.33 (5.57) points. The full analysis set included 105 patients (80 patients with hereditary, 25 with nonhereditary or unknown cerebellar ataxia). There was no evidence of a difference in the mean absolute change from baseline to week 6 in SARA total scores between both treatments (mean treatment difference: 0.23 points [95% CI, -0.40 to 0.85 points])., Conclusions and Relevance: In this large multicenter, double-blind, randomized, placebo-controlled clinical crossover trial, acetyl-DL-leucine in the investigated dosage and treatment duration was not superior to placebo for the symptomatic treatment of certain types of ataxia. The drug was well tolerated; and ALCAT yielded valuable information about the duration of treatment periods and the role of placebo response in cerebellar ataxia. These findings suggest that further symptom-oriented trials are needed for evaluating the long-term effects of acetyl-DL-leucine for well-defined subgroups of cerebellar ataxia., Trial Registration: EudraCT 2015-000460-34.

Background and Objective: To present 6 new cases with Homer-3 antibodies that expand their clinical spectra and to evaluate the effect of immunotherapy., Methods: Patients with suspected autoimmune cerebellar disorder were tested for rare autoimmune cerebellar ataxia (ACA) antibodies (anti-Tr(DNER)/Zic4/ITPR1/Homer-3/NCDN/PKCγ/PCA-2/AP3B2/mGluR1/ATP1A3 antibodies) using both cell-based and tissue-based assays. Patients with positive serum or CSF results who were diagnosed with ACA were registered and followed up. This study reports and analyzes cases with Homer-3 antibodies., Results: Of the serum and CSF samples of 750 patients tested, 6 were positive for Homer-3 antibodies. All manifested subacute or insidious-onset cerebellar ataxia. Furthermore, 2 patients each exhibited encephalopathy, myeloradiculopathy, REM sleep behavior disorder, and autonomic dysfunction. Brain magnetic resonance images were normal (n = 1) or revealed cerebellar atrophy (n = 1), cerebellum and pons atrophy with the hot cross bun sign (n = 2), and bilateral cerebral abnormalities (n = 2). Definite leukocytosis was identified in the CSF of 2 patients, protein concentration elevation was observed in the CSF of 1 patient, and oligoclonal bands were present in 2 patients. All patients received immunotherapy, including corticosteroid, IV immunoglobulin, plasma exchange, and mycophenolate mofetil, after which the residual disability was still severe (modified Rankin Scale score ≥3 at the last follow-up in 4 patients and final Scale for the Assessment and Rating of Ataxia scores of 12-29), although 4 patients partially improved and 1 patient stabilized. The remaining 1 patient continued to deteriorate after repeated immunotherapy. Two patients relapsed., Discussion: Disorders associated with Homer-3 antibody can mimic multiple system atrophy with cerebellar features in both clinical and radiologic aspects. Accurate identification of autoimmune-mediated cases is critical. Timely, comprehensive immunotherapy is warranted, given the possibility of long-term clinical benefit., (Copyright © 2021 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.)

Kv1.2 channels, encoded by the KCNA2 gene, are localized in the central and peripheral nervous system, where they regulate neuronal excitability. Recently, heterozygous mutations in KCNA2 have been associated with a spectrum of symptoms extending from epileptic encephalopathy, intellectual disability, and cerebellar ataxia. Patients are treated with a combination of antiepileptic drugs and 4-aminopyridine (4-AP) has been recently trialed in specific cases. We identified a novel variant in KCNA2 , E236K, in a Serbian proband with non-progressive congenital ataxia and early onset epilepsy, treated with sodium valproate. To ascertain the pathogenicity of E236K mutation and to verify its sensitivity to 4-AP, we transfected HEK 293 cells with Kv1.2 WT or E236K cDNAs and recorded potassium currents through the whole-cell patch-clamp. In silico analysis supported the electrophysiological data. E236K channels showed voltage-dependent activation shifted towards negative potentials and slower kinetics of deactivation and activation compared with Kv1.2 WT. Heteromeric Kv1.2 WT+E236K channels, resembling the condition of the heterozygous patient, confirmed a mixed gain- and loss-of-function (GoF/LoF) biophysical phenotype. 4-AP inhibited both Kv1.2 and E236K channels with similar potency. Homology modeling studies of mutant channels suggested a reduced interaction between the residue K236 in the S2 segment and the gating charges at S4. Overall, the biophysical phenotype of E236K channels correlates with the mild end of the clinical spectrum reported in patients with GoF/LoF defects. The response to 4-AP corroborates existing evidence that KCNA2 -disorders could benefit from variant-tailored therapeutic approaches, based on functional studies.

The spectrum of anti-contactin-associated protein-like 2 (CASPR2) antibody-associated disease is expanding and the involvement of cerebellum was reported in the past few years. We report a 45-year-old male with chronically progressive cerebellar ataxia. CASPR2 antibodies were detected in his serum and cerebellar atrophy was observed on MRI. His symptoms improved prominently with steroids and intravenous immunoglobulins. 23 cases with CASPR2 antibodies and cerebellar ataxia were identified from previous publications. Most of patients showed acute or subacute onset with other typical presentations of anti-CASPR2 antibody-associated disease, such as limbic encephalitis. Immunotherapy was effective in the majority of patients., (Copyright © 2021. Published by Elsevier B.V.)

Mutations in AarF domain-containing kinase 3 (ADCK3) are responsible for the most frequent form of hereditary coenzyme Q10 (CoQ10) deficiency (Q10 deficiency-4), which is mainly associated with autosomal recessive cerebellar ataxia type 2 (ARCA2). Clinical presentation is characterized by a variable degree of cerebellar atrophy and a broad spectrum of associated symptoms, including muscular involvement, movement disorders, neurosensory loss, cognitive impairment, psychiatric symptoms and epilepsy. In this report, we describe, for the first time, a case of photoparoxysmal response in a female patient with a mutation in ADCK3. Disease onset occurred in early childhood with gait ataxia, and mild-to-moderate degeneration. Seizures appeared at eight years and six months, occurring only during sleep. Photoparoxysmal response was observed at 14 years, almost concomitant with the genetic diagnosis (c.901C>T;c.589-3C>G) and the start of CoQ10 oral supplementation. A year later, disease progression slowed down, and photosensitivity was attenuated. A review of the literature is provided focusing on epileptic features of ADCK3-related disease as well as the physiopathology of photoparoxysmal response and supposed cerebellar involvement in photosensitivity. Moreover, the potential role of CoQ10 oral supplementation is discussed. Prospective studies on larger populations are needed to further understand these data.

Acquired cerebellar ataxia is a rare, in many cases immune-modulated and paraneoplastic illness. Acute and slowly progredient processes are possible. An early treatment is important for a good clinical outcome. Here we present the case of female patient in her 60s with an antirecoverin associated cerebellitis without retinopathia and neoplasia. After an immunosuppressive therapy with steroids and rituximab the symptoms improved, and the progression could be stopped., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2020. No commercial re-use. See rights and permissions. Published by BMJ.)

Although the classic phenotype of episodic ataxia type 1 (EA1) caused by variants in KCNA1 includes episodic ataxia and myokymia, further genotype-phenotype correlations are difficult to establish due to highly heterogeneous clinical presentations associated with KCNA1 pathogenic variants. De novo variants in the paralogous Pro-Val-Pro motif (PVP) of KCNA2, an essential region for channel gating, have been reported to be associated with severe epilepsy phenotypes, including developmental and epileptic encephalopathies (DEE). Here, we describe the first patient with a DEE who developed an encephalopathy related to status epilepticus during sleep (ESES) and cerebellar signs, harbouring a variant in the Kv-specific PVP motif of the KCNA1 gene. Interestingly, he showed a remarkable long-term electroclinical response to IM ACTH therapy. This report extends the range of phenotypes associated with KCNA1 variants to include that of ESES, and suggests that ACTH therapy is likely to have a positive effect in patients with these variants.

Antibodies against metabotropic glutamate receptor type 1 (mGluR1) have been described in adults with paraneoplastic or non-paraneoplastic subacute cerebellitis. Patients responded to immunotherapy depending on disease duration. Here, we report on a 3 years 2 months old male toddler with acute onset ataxia and mGluR1 antibodies in serum and cerebrospinal fluid (CSF). He was started on prednisolone 4 weeks after disease onset and remitted largely within half a year., Competing Interests: Declaration of Competing Interest CGB obtained honoraria for speaking engagements from UCB (Monheim, Germany) and Desitin (Hamburg, Germany). He receives research support from Deutsche Forschungsgemeinschaft (German Research Council, Bonn, Germany) and Gerd-Altenhof-Stiftung (Deutsches Stiftungs-Zentrum, Essen, Germany). The other authors have no disclosures., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Ataxia, characterized by uncoordinated movement, is often found in patients with cerebellar hemorrhage (CH), leading to long-term disability without effective management. Microglia are among the first responders to CNS insult. Yet the role and mechanism of microglia in cerebellar injury and ataxia after CH are still unknown. Using Ki20227, an inhibitor for colony-stimulating factor 1 receptor which mediates the signaling responsible for the survival of microglia, we determined the impact of microglial depletion on cerebellar injury and ataxia in a murine model of CH. Microglial depletion reduced cerebellar lesion volume and alleviated gait abnormality, motor incoordination, and locomotor dysfunction after CH. Suppression of CH-initiated microglial activation with minocycline ameliorated cerebellum infiltration of monocytes/macrophages, as well as production of proinflammatory cytokines and chemokine C-C motif ligand-2 (CCL-2) that recruits monocytes/macrophages. Furthermore, both minocycline and bindarit, a CCL-2 inhibitor, prevented apoptosis and electrophysiological dysfunction of Purkinje cells, the principal neurons and sole outputs of the cerebellar cortex, and consequently improved ataxia-like motor abnormalities. Our findings suggest a detrimental role of microglia in neuroinflammation and ataxic motor symptoms after CH, and pave a new path to understand the neuroimmune mechanism underlying CH-induced cerebellar ataxia., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Immune-mediated ataxias account for a substantial number of sporadic otherwise idiopathic ataxias. Despite some well-characterised entities such as paraneoplastic cerebellar degeneration where diagnostic markers exist, the majority of immune ataxias remained undiagnosed and untreated. We present here our experience in the treatment of suspected primary autoimmune cerebellar ataxia (PACA) using mycophenolate. All patients reported attend the Sheffield Ataxia Centre on a regular basis and had undergone extensive investigations, including genetic testing using next-generation sequencing, with other causes of ataxia excluded. The diagnosis of PACA was strongly suspected based on investigations, pattern of disease progression, and cerebellar involvement. Patients were treated with mycophenolate and monitored using MR spectroscopy of the cerebellar vermis. Thirty patients with PACA are reported here. Of these, 22 received mycophenolate (group 1). The remaining 8 were not on treatment (group 2-control group). Out of the 22 treated patients, 4 underwent serial MR spectroscopy prior to starting treatment and thus were used as controls making the total number of patients in the control group 12. The mean change of the MRS within the vermis (NAA/Cr area ratio) in the treatment group was + 0.144 ± 0.09 (improved) and in the untreated group - 0.155 ± 0.06 (deteriorated). The difference was significant. We also demonstrated a strong correlation between the spectroscopy and the SARA score. We have demonstrated the effectiveness of mycophenolate in the treatment of PACA. The results suggest that immune-mediated ataxias are potentially treatable, and that there is a need for early diagnosis to prevent permanent neurological deficit. The recently published diagnostic criteria for PACA would hopefully aid the diagnosis and treatment of this entity.

A prompt diagnosis and treatment of patients with autoimmune cerebellar ataxia (CA) with antibodies against glutamic acid decarboxylase (GAD-Abs) may lead to a better prognosis. Herein, we report prodromal transient neurological symptoms that should raise clinical suspicion of CA with GAD-Abs. We initially identified a 70-year-old man who presented a first acute episode of vertigo, diplopia, and ataxia lasting 2 weeks. Two months later, he experienced a similar episode along with new-onset gaze-evoked nystagmus. After 4 months, downbeat nystagmus, left limb dysmetria, and gait ataxia progressively appeared, and an autoimmune CA was diagnosed based on the positivity of GAD-Abs in serum and cerebrospinal fluid (CSF). We searched retrospectively for similar presentations in a cohort of 31 patients diagnosed with CA and GAD-Abs. We found 11 (35.4%) patients (all women, median age 62 years; 8/11 [72.7%] with autoimmune comorbidities) with transient neurological symptoms antedating CA onset by a median of 3 months, including vertigo in 9 (81.8%; described as paroxysmal in 8) and fluctuating diplopia in 3 (27.3%) patients. The identification of transient neurological symptoms of unknown etiology, such as paroxysmal vertigo and fluctuating diplopia, should lead to GAD-Abs testing in serum and CSF, especially in patients with autoimmune comorbidities.

Combined checkpoint inhibition therapy targeting the programmed cell death 1 (PD-L1) and cytotoxic T-lymphocyte associated protein 4 pathways has been a successful approach in the treatment of metastatic melanoma, leading to its investigation in the treatment of head and neck squamous cell carcinoma (HNSCC) with PD-L1 expression. Despite the potential for excellent responses, an increased rate of autoimmune neurological toxicity and paraneoplastic conditions has been observed when using these treatment modalities. We present the case of a patient with metastatic HNSCC treated with combination ipilimumab/nivolumab who experienced severe cerebellar ataxia with a positive screen for the anti-Zic4 antibody. This is the first case, to our knowledge, of anti-Zic4 antibody-mediated cerebellar toxicity reported in association with HNSCC. Although the patient experienced an impressive partial response with dual checkpoint inhibition, he suffered grade 4 neurotoxicity. Despite exciting advances in cancer immunotherapy, clinicians must be aware of the rare, debilitating and possibly previously undescribed paraneoplastic and autoimmune toxicities that may occur., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

A 30-year-old woman presented with recurrent hiccups, vomiting and painful diminution of vision and gait instability for 1 day. She had one-and-a-half syndrome, bilateral seventh cranial nerve paresis with bilateral symptomatic optic neuritis and left-sided ataxic haemiparesis. We described her disorder as the 'twenty syndrome' (1 1 / 2 +7+7+2+2+½=20). MRI of her brain revealed demyelination predominantly in right posterolateral aspect of pons, medulla and bilateral optic nerves. Serum antiaquaporin-4 antibody came out positive. Thus, she was diagnosed as neuromyelitis optica spectrum disorder (NMOSD). She responded brilliantly to immunosuppressive therapy. This is the first ever reported case of the 'twenty syndrome' secondary to cerebral NMOSD., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2020. No commercial re-use. See rights and permissions. Published by BMJ.)

Cerebellar ataxia is a neurodegenerative disorder with no definitive treatment. Although several studies have demonstrated the neuroprotective effects of Hericium erinaceus (H.E.), its mechanisms in cerebellar ataxia remain largely unknown. Here, we investigated the neuroprotective effects of H.E. treatment in an animal model of 3-acetylpyridine (3-AP)-induced cerebellar ataxia. Animals administered 3-AP injection exhibited remarkable impairments in motor coordination and balance. There were no significant effects of 25 mg/kg H.E. on the 3-AP treatment group compared to the 3-AP saline group. Interestingly, there was also no significant difference in the 3-AP treatment group compared to the non-3-AP control, indicating a potential rescue of motor deficits. Our results revealed that 25 mg/kg H.E. normalised the neuroplasticity-related gene expression to the level of non-3-AP control. These findings were further supported by increased protein expressions of pERK1/2-pCREB-PSD95 as well as neuroprotective effects on cerebellar Purkinje cells in the 3-AP treatment group compared to the 3-AP saline group. In conclusion, our findings suggest that H.E. potentially rescued behavioural motor deficits through the neuroprotective mechanisms of ERK-CREB-PSD95 in an animal model of 3-AP-induced cerebellar ataxia.

Cerebellar ataxia-predominant multiple system atrophy (MSA-C) and cortical cerebellar atrophy are representative diseases of adult-onset sporadic degenerative ataxia. Both diseases are distinctly different because of α-synuclein pathology. However, it takes approximately 2 years for cerebellar ataxia to progress to concomitant severe autonomic dysfunction in patients with MSA-C. The period of only cerebellar ataxia (mono system atrophy) may extend to more than 10 years. Understanding mono system atrophy is vital for the early diagnosis and drug development for MSA. In this review, we discuss mono system atrophy focusing on the concept and natural history and the possibility of the of early diagnosis and disease-modifying therapy for MSA.

Human herpesvirus 6 (HHV-6) infection is the cause of roseola infantum in children. The reactivation of HHV-6 is associated with multiple clinical syndromes including encephalitis and myelitis, especially in haematopoietic stem cell transplant recipients. However, the virus can cause encephalitis in other immunosuppressed as well as immunocompetent individuals. We report a case of a 70-year-old woman who was immunocompromised secondary to treatment of rheumatoid arthritis with leflunomide and methotrexate. The patient presented with acute ataxia, diplopia and dysarthria. MRI brain showed an enhancing lesion in the midbrain. The diagnosis of HHV-6 encephalitis was made after HHV-6 A DNA was detected in both serum and cerebrospinal fluid. Treatment consisted of a 3-week course of intravenous ganciclovir along with physiotherapy. At a 3-month follow-up, repeat MRI brain showed a decrease in size and oedema of the lesion and the patient's neurological function was improved., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2020. No commercial re-use. See rights and permissions. Published by BMJ.)

We present a case of Legionnaires' disease complicated by cerebellar ataxia. A 60-year-old man was diagnosed with Legionnaires' disease by urine antigen after presenting to the hospital with a main problem of headache and gait instability. He also had a productive cough, as well as nausea, vomiting and diarrhoea. Initial physical examination revealed a positive Romberg test, positive pronator drift, severely unsteady gait and bilateral upper extremity resting tremors with the remainder of cranial nerves and neurological examination being unremarkable. The patient had a prolonged hospital course requiring endotracheal intubation and mechanical ventilation. He received 14 days of levofloxacin with resolution of the pneumonia. On repeat assessment prior to discharge, the patient's neurological symptoms improved; however, he still had mild residual gait instability, dysdiadokinesia and difficulty with fine motor tasks such as writing. Romberg test remained positive., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2020. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective: Antibodies against glutamic acid decarboxylase 65 (anti-GAD65) are associated with a number of neurologic syndromes. However, their pathogenic role is controversial. Our objective was to describe clinical and paraclinical characteristics of anti-GAD65 patients and analyze their response to immunotherapy., Methods: Retrospectively, we studied patients (n = 56) with positive anti-GAD65 and any neurologic symptom. We tested serum and CSF with ELISA, immunohistochemistry, and cell-based assay. Accordingly, we set a cutoff value of 10,000 IU/mL in serum by ELISA to group patients into high-concentration (n = 36) and low-concentration (n = 20) groups. We compared clinical and immunologic features and analyzed response to immunotherapy., Results: Classical anti-GAD65-associated syndromes were seen in 34/36 patients with high concentration (94%): stiff-person syndrome (7), cerebellar ataxia (3), chronic epilepsy (9), limbic encephalitis (9), or an overlap of 2 or more of the former (6). Patients with low concentrations had a broad, heterogeneous symptom spectrum. Immunotherapy was effective in 19/27 treated patients (70%), although none of them completely recovered. Antibody concentration reduction occurred in 15/17 patients with available pre- and post-treatment samples (median reduction 69%; range 27%-99%), of which 14 improved clinically. The 2 patients with unchanged concentrations showed no clinical improvement. No differences in treatment responses were observed between specific syndromes., Conclusion: Most patients with high anti-GAD65 concentrations (>10,000 IU/mL) showed some improvement after immunotherapy, unfortunately without complete recovery. Serum antibody concentrations' course might be useful to monitor response. In patients with low anti-GAD65 concentrations, especially in those without typical clinical phenotypes, diagnostic alternatives are more likely., (Copyright © 2020 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.)