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Chorea is a hyperkinetic movement disorder associated with various underlyingconditions, including autoimmune diseases such as antiphospholipid syndrome (APS). APS can manifest with a wide range of neurological symptoms, including chorea. We present a case of a 77-year-old man with subacute generalized chorea secondary to primary APS. Notably, the patient exhibited a left patellar crossed-reflex, a phenomenon rarely documented in chorea cases, the pathophysiology of which has not yet been elucidated. In summary, this case challenges the traditional demographics of antiphospholipid syndrome (APS) by suggesting a potential link between APS and late-age patients. It emphasizes the importance of considering APS in late-onset chorea cases., (© 2024. The Author(s).)

Background: Subacute sclerosing panencephalitis (SSPE) is a complication of measles, occurring after a latency of 4-10 years. It continues to occur in developing countries although resurgence is being reported from developed countries. Characteristic features include progressive neuropsychiatric issues, myoclonus, seizures, movement disorders and visual impairment. Electroencephalography (EEG) typically shows periodic generalized discharges, and elevated CSF anti-measles antibodies are diagnostic. Movement disorders are being increasingly recognized as part of the clinical spectrum, and range from hyperkinetic (chorea, dystonia, tremor, tics) to hypokinetic (parkinsonism) disorders and ataxia., Objectives: This article aims to comprehensively review the spectrum of movement disorders associated with SSPE., Methods: A literature search was conducted in PubMed and EMBASE databases in December 2023 and articles were identified for review., Results: Movement disorders reported in SSPE included hyperkinetic (chorea, dystonia, tremor and tics), hypokinetic (parkinsonism), ataxia and extraocular movement disorders. Myoclonus, a core clinical feature, was the most frequent "abnormal movement." Movement disorders were observed in all clinical stages, and could also be a presenting feature, even sans myoclonus. Hyperkinetic movement disorders were more common than hypokinetic movement disorders. An evolution of movement disorders was observed, with ataxia, chorea and dystonia occurring earlier, and parkinsonism later in the disease. Neuroradiological correlates of movement disorders remained unclear., Conclusion: A wide spectrum of movement disorders was observed throughout the clinical stages of SSPE. Most data were derived from case reports and small case series. Multicentric longitudinal studies are required to better delineate the spectrum and evolution of movement disorders in SSPE., (© 2024 International Parkinson and Movement Disorder Society.)

Background: Although infrequent, Sydenham's chorea (SC) may occur as a result of injury to the basal ganglia in children with acute rheumatic fever (ARF) secondary to group A Streptococcal infection. Certain hallmarks of SC, such as movement disorders, could be utilized as a predictive marker for carditis. The present study aimed to investigate neurologic and cardiologic symptoms in children with suspected SC after ARF., Methods: All children aged 5-16 who were admitted at Shahid Madani Pediatric Hospital (Tabriz, Iran), with an initial diagnosis of ARF and SC between 2009 and 2022 were included for echocardiographic assessment and prospective follow-up within 6 and 12 months after the start point. The pattern and severity of valvulopathy, as well as the prevalence of Jones criteria for rheumatic fever, were used to assess the effect. The collected data were analyzed using SPSS Statistics software (version 22.0) using Chi square and Fisher's exact tests. P<0.05 was considered statistically significant., Results: The study enrolled 85 children, 36 girls and 49 boys, with a mean age of 9.7±2.7. On the first echocardiography, 42.4% of patients had mitral valve regurgitation (MR), with a predominance of female patients (P=0.04). Of those diagnosed with SC (12 girls and 6 boys), 66.7% showed cardiac involvement, with a higher prevalence of MR in both sexes (P=0.04). The pattern of cardiac involvement after 6 months was significantly different between the groups (P=0.04). However, no such difference was observed during the one-year follow-up (P=0.07). Female sex was found to have a significant relationship with SC localization (P=0.01)., Conclusion: In addition to its neurological manifestations, SC can be associated with clinical or subclinical cardiac valve dysfunction that might last for more than a year. In addition to attempting early detection and appropriate management, a precise cardiac and neurologic assessment during admission and follow-up is recommended.A preprint version of this manuscript is available at DOI: 10.21203/rs.3.rs-772662/v1 (https://www.researchsquare.com/article/rs-772662/v1)., Competing Interests: None declared., (Copyright: © Iranian Journal of Medical Sciences.)

Background: Subacute Sclerosing Panencephalitis (SSPE) typically presents with periodic myoclonus; however, a spectrum of movement disorders including dystonia, chorea, tremor, and parkinsonism have also been described. This review aims to evaluate the array of movement disorders in SSPE, correlating them with neuroimaging findings, disease stages, and patient outcomes., Methods: A comprehensive review of published case reports and case series was conducted on patients with SSPE exhibiting movement disorders other than periodic myoclonus. PRISMA guidelines were followed, and the protocol was registered with PROSPERO (2023 CRD42023434650). A comprehensive search of multiple databases yielded 37 reports detailing 39 patients. Dyken's criteria were used for SSPE diagnosis, and the International Movement Disorders Society definitions were applied to categorize movement disorders., Results: The majority of patients were male, with an average age of 13.8 years. Approximately, 80% lacked a reliable vaccination history, and 39% had prior measles infections. Dystonia was the most common movement disorder (49%), followed by parkinsonism and choreoathetosis. Rapid disease progression was noted in 64% of cases, with a disease duration of ≤6 months in 72%. Neuroimaging showed T2/FLAIR MR hyperintensities, primarily periventricular, with 26% affecting the basal ganglia/thalamus. Brain biopsies revealed inflammatory and neurodegenerative changes. Over half of the patients (56%) reached an akinetic mute state or died., Conclusion: SSPE is associated with diverse movement disorders, predominantly hyperkinetic. The prevalence of dystonia suggests basal ganglia dysfunction., Competing Interests: The authors have no competing interests to declare., (Copyright: © 2024 The Author(s).)

Introduction: Chorea is primarily due to an imbalance of basal ganglia output pathways, often due to dysfunction or degeneration of the caudate nucleus and putamen, and can be due to many causes., Methods: We reviewed the recent literature to identify newly-recognized causes of chorea, including auto-immune, metabolic, and genetic. We also focused upon developments in mechanisms relating to underlying pathophysiology of certain genetic choreas and advances in therapeutics., Results: Novel autoantibodies continue to be identified as causes of chorea. Both COVID-19 infection and vaccination are reported to result rarely in chorea, although in some cases causality is not clearly established. Advances in genetic testing continue to find more causes of chorea, and to expand the phenotype of known genetic disorders. Deep brain stimulation can be successful in certain circumstances., Conclusion: Our understanding of mechanisms underlying this movement disorder continues to advance, however much remains to be elucidated., Competing Interests: Declaration of competing interest There are no competing interests., (Published by Elsevier Ltd.)

Paroxysmal movement disorders include two groups of intermittent neurologic disorders: paroxysmal dyskinesia, in which episodes of involuntary hyperkinetic movements (mainly chorea and/or dystonia) occur with preserved consciousness, and episodic ataxias, which are characterized by discrete attacks of cerebellar dysfunction, sometimes associated with progressive ataxia. Since episodic ataxias are individually discussed in Chapter 8 of this volume, we herein provide a deep overview of phenotypic, genetic, pathophysiologic, diagnostic, and treatment aspects of paroxysmal dyskinesia, following the trigger-based nomenclature which distinguishes paroxysmal kinesigenic dyskinesia, paroxysmal nonkinesigenic dyskinesia, and paroxysmal exercise-induced dyskinesia. Emerging paroxysmal dyskinesia not fulfilling the criteria for the above-mentioned subtypes will also be discussed. Phenotypic and genotypic overlap among paroxysmal movement disorders, epilepsy, and migraine have progressively emerged, thus shedding light on a shared pathophysiologic framework. Advances in our understanding of the pathomechanisms underlying paroxysmal movement disorders, which involve dysfunctions of ion channels, proteins associated with the vesical synaptic cycle machinery, and proteins involved in neuronal energy metabolism, point toward a discrete number of converging pathophysiologic pathways and may lay foundations for developing target-specific therapies., (Copyright © 2024 Elsevier B.V. All rights are reserved, including those for text and data mining, AI training, and similar technologies.)

Background: Type III 3-methylglutaconic aciduria (OPA 3) is a neuro-ophthalmologic syndrome consisting of early-onset bilateral optic atrophy. Since Costeff described the phenotype of 19 patients in 1989, several reports described approximately 50 patients, but most of them lack details about neuro-ophthalmic phenotype. Our aim was to characterize the clinical neuro-ophthalmic phenotype of this syndrome., Methods: Nine patients underwent meticulous visual function history and medical documents' review. Results of best-corrected visual acuity (VA), color vision, visual field (VF), ocular motility, pupillary reaction, slit-lamp, and dilated fundus examinations were recorded. Optical coherence tomography (OCT) was performed whenever possible., Results: The average VA was 1.4 ± 0.8 logarithm of the minimum angle of resolution. Poor vision was the presenting symptom in 5 patients. Six patients had decreased VA and variable degrees of optic atrophy. Humphrey VF testing of 7 patients revealed generalized depression in 5 and a cecocentral defect in 2. All patients demonstrated dysmetric saccades. Four patients had strabismus, 3 with exotropia, and one with esotropia. Seven patients had nystagmus. Ocular motility abnormality is possibly the result of cerebellar atrophy that was found in MRI studies of our patients. OCT of the retina was possible in 6 patients and revealed retinal nerve fiber layer (RNFL) thinning as well as average retinal thinning. Three patients, in whom ganglion cell layer-inner plexiform layer (IPL) measurement was possible, also showed diffused thinning., Conclusions: This study compiled data regarding neuro-ophthalmic manifestation of OPA 3 Type III patients. Contrary to established literature, poor vision was the presenting symptom in only 50% of our patients. This is the first report of OCT findings in 3MGA patients. The results demonstrated diffused thinning of the RNFL and ganglion cell complex-IPL with correlation to VA, which is in contrast to OPA1 patients in whom the most severe thinning is at the level of the papillomacular bundle. Average retinal thinning was identified at second and third decades of life, possibly resulting from early ganglion cell loss. These results may contribute to visual prognosis, and OCT may help monitor experimental therapies., Competing Interests: G. Yahalom received consultation fee from AbbVie Inc. The remaining authors report no conflicts of interest., (Copyright © 2021 by North American Neuro-Ophthalmology Society.)

Objectives: The objective of this study is to describe the mechanism of damage to subcortical structures in chronic kidney disease (CKD) and to describe the range of movement disorders associated with CKD., Materials and Methods: We have reviewed the Medline literature up to January of 2020 using key words movement disorders and chronic kidney disease. The reviewed articles were studied for mechanisms of subcortical damage in CKD as well as type of the reported movements, their frequency and updated treatment., Results: The search revealed 183 articles most of them dealing with restless legs syndrome. The damage to basal ganglia in CKD resulted from several mechanisms including accumulation of nitro tyrosine caused by reactive oxygen species and action of uremic toxins leading to endothelial damage and dysfunction of blood-brain barrier. Involuntary movements in CKD include restless legs syndrome (RLS), myoclonus, asterixis, dystonia, chorea, tremor, and Parkinsonism., Conclusions: Chronic kidney disease can cause several abnormal involuntary movements via damaging basal ganglia and subcortical structures. The most common movement disorders in CKD are RLS, myoclonus and asterixis. Restless legs syndrome and myoclonus when severe, need and respond to treatment. Movement disorders in CKD improve with improvement of kidney function., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: Although NKX 2.1 related chorea has been considered benign due to the favourable course of motor phenotype during life, the neurological condition is not limited to chorea, including non-motor symptoms in the developmental, cognitive and psychiatric domain. Aim of our study was to test working memory, attention and planning abilities of a cohort of NKX2.1 choreic patients compared to healthy controls., Methods: patients and healthy controls were assessed for working memory (Visual Digit Span test), response inhibition and sustained attention (Cued Go/No-Go test), and spatial problem-solving and planning task (Tower of London test). For experimental protocol, we used a computer based tool for neuropsychological experiments, Inquisit 5.0 software (Millisecond Software®). Non-parametric tests were performed for statistical analysis., Results: six patients and fifteen healthy paediatric controls were recruited. In the Digit Span test, both in forward and backward recall, patients showed statistically significant lower scores than controls. In the Cued Go/No-Go test as well as in the Tower of London, NKX 2.1 patients showed similar scores in the error rate and total score respectively, whereas in both tests they appeared to be slower than controls suggesting a poor performance in the execution of the tests., Conclusions: our findings demonstrate that patients with NKX2.1-related chorea show a selective impairment in working memory with increased latencies in both planning and attention. A developmental alteration of the cholinergic neurotransmission in the basal forebrain and the disruption of striatal networks could explain, at least in part, this neuropsychological profile., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Objective: We aimed to characterize the phenotypic spectrum and functional consequences associated with variants in the gene GABRB2, coding for the γ-aminobutyric acid type A (GABA A ) receptor subunit β2., Methods: We recruited and systematically evaluated 25 individuals with variants in GABRB2, 17 of whom are newly described and 8 previously reported with additional clinical data. Functional analysis was performed using a Xenopus laevis oocyte model system., Results: Our cohort of 25 individuals from 22 families with variants in GABRB2 demonstrated a range of epilepsy phenotypes from genetic generalized epilepsy to developmental and epileptic encephalopathy. Fifty-eight percent of individuals had pharmacoresistant epilepsy; response to medications targeting the GABAergic pathway was inconsistent. Developmental disability (present in 84%) ranged from mild intellectual disability to severe global disability; movement disorders (present in 44%) included choreoathetosis, dystonia, and ataxia. Disease-associated variants cluster in the extracellular N-terminus and transmembrane domains 1-3, with more severe phenotypes seen in association with variants in transmembrane domains 1 and 2 and the allosteric binding site between transmembrane domains 2 and 3. Functional analysis of 4 variants in transmembrane domains 1 or 2 (p.Ile246Thr, p.Pro252Leu, p.Ile288Ser, p.Val282Ala) revealed strongly reduced amplitudes of GABA-evoked anionic currents., Interpretation: GABRB2-related epilepsy ranges broadly in severity from genetic generalized epilepsy to developmental and epileptic encephalopathies. Developmental disability and movement disorder are key features. The phenotypic spectrum is comparable to other GABA A receptor-encoding genes. Phenotypic severity varies by protein domain. Experimental evidence supports loss of GABAergic inhibition as the mechanism underlying GABRB2-associated neurodevelopmental disorders. ANN NEUROL 2021;89:573-586., (© 2020 American Neurological Association.)

Hemichorea and other hyperkinetic movement disorders are a rare presentation of stroke, usually secondary to deep infarctions affecting the basal ganglia and the thalamus. Chorea can also result from lesions limited to the cortex, as shown in recent reports. Still, the pathophysiology of this form of cortical stroke-related chorea remains unknown. We report 4 cases of acute ischemic cortical strokes presenting as hemichorea, with the infarction being limited to the parietal and insular cortex in perfusion computed tomography scans and magnetic resonance imaging. These cases suggest potential dysfunction of pathways connecting these cortical regions with the basal ganglia., Competing Interests: Declaration of Competing Interest None., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Mutations in RNF216 have been found to be associated with autosomal recessive Huntington-like disorder. Here, we describe a patient with Huntington-like disorder caused by a novel de novo RNF216 mutation. The patient started to have choreatic movements of both hands, slowly progressing to head, face, and four extremities, with prominent cognitive deterioration. White matter lesions in cerebral hemispheres and brainstem, cerebellar atrophy, and low gonadotropin serum levels have been demonstrated. We have identified a homozygous deletion of exon 2 in the RNF216 gene by whole-exome sequencing. Our findings increased genetic knowledge of autosomal recessive Huntington-like disorder and extended the ethnic distribution of RNF216 mutations., (© 2020 The Authors. Annals of Clinical and Translational Neurology published by Wiley Periodicals LLC on behalf of American Neurological Association.)

Background: Basal ganglia (BG) lesions are rarely reported in patients with uremia and may manifest by movement disorders. However, their exact incidence and pathogenesis have not been extensively studied. This study aimed to determine the frequency, types, risk variables (clinical, laboratory, and imaging), and manifestations of BG lesions with uremia and patients' neurologic outcomes., Methods: This observational study included 70 adults (mean age: 45.87 ± 3.36 years; duration of uremia: 5.5 ± 1.5 years). They underwent extensive evaluations (clinical, laboratory, and neuroimaging) and had prospectively evaluated clinically every 3 months for 2 years. Repeated magnetic resonance imaging (MRI) brains were done to patients with movement disorders and correlated with their neurologic outcomes., Results: BG lesions were found in 15 patients (21.4%) and 6 (8.6%) had movement disorders [Parkinsonism (n = 4), choreo-dystonia (n = 1) and dystonia (n = 1)] after the onset of uremia (mean = 10 months). There were no characteristic risk variables that distinguished patients with movement disorders from those without. Five developed movement disorders prior to the period of the study and one was de novo. The majority was females and had diabetes and higher frequencies of abnormal renal dysfunction, metabolic derangements, and white matter hyperintensities in MRIs. Movement disorders persisted in all patients despite the resolution of neuroimaging in three patients., Conclusions: There is no clear threshold for renal failure to result in movement disorders due to BG lesions. The clinical outcome is variables depending on each patient's comorbidities and complications. Persistent neuronal damage (due to uremic toxins/metabolic/nutritional and ischemic/microvascular factors) has been suggested as the cause of poor neurologic outcomes.

Immune response against neuronal and glial cell surface and cytosolic antigens is an important cause of encephalitis. It may be triggered by activation of the immune system in response to an infection (para-infectious), cancer (paraneoplastic), or due to a patient's tendency toward autoimmunity. Antibodies directed toward neuronal cell surface antigens are directly pathogenic, whereas antibodies with intracellular targets may become pathogenic if the antigen is transiently exposed to the cell surface or via activation of cytotoxic T cells. Immune-mediated encephalitis is well recognized and may require intensive care due to status epilepticus, need for invasive ventilation, or dysautonomia. Patients with immune-mediated encephalitis may become critically ill and display clinically complex and challenging to treat movement disorders in over 80% of the cases (Zhang et al. in Neurocrit Care 29(2):264-272, 2018). Treatment options include immunotherapy and symptomatic agents affecting dopamine or acetylcholine neurotransmission. There has been no prior published guidance for management of these movement disorders for the intensivist. Herein, we discuss the immune-mediated encephalitis most likely to cause critical illness, clinical features and mechanisms of movement disorders and propose a management algorithm.

Paroxismal non-kinesigenic dyskinesia (PNKD) is a rare movement disorder manifesting as choreatic/dystonic movements, usually lasting from minutes to up to 4 h, with perserved consciousness during attacks. Primary PNKD are idiopathic or genetic disorders while secondary PNKD are associated with various neurologic and medical conditions. We present a case with PNKD and right sided hemidystonia in association with celiac disease, responsive to gluten-free diet, not previously reported in available literature. In conclusion, diagnostic tests for celiac disease should be a part of etiological investigations in patients with otherwise unexplained movement disorders including PKND. Gluten free diet could produce a favorable clinical response in those patients., (Copyright © 2019. Published by Elsevier B.V.)

Background: Huntington Disease-Like 2 (HDL2) is a rare autosomal dominant disorder caused by an abnormal CAG/CTG triplet repeat expansion on chromosome 16q24. The symptoms of progressive decline in motor, cognitive and psychiatric functioning are similar to those of Huntington's disease (HD). The psychiatric features of the HDL2 have been poorly characterized., Objective: To describe the neuropsychiatric features of HDL2 and compare them with those of HD., Methods: A blinded cross-sectional design was used to compare the behavioural component of the Unified Huntington's Disease Rating Scale (UHDRS) in participants with HDL2 (n = 15) and HD (n = 13) with African ancestry., Results: HDL2 patients presented with psychiatric symptoms involving mood disturbances and behavioural changes that were not significantly different from those in the HD group. Duration of disease and motor performance correlated (p < 0.001) with the Functional Capacity score and the Independence score of the UHDRS. HD patients reported movement dysfunction as the first symptom more frequently than HDL2 Patients (p < 0.001)., Conclusion: The psychiatric phenotype of HDL2 is similar to that of HD and linked to motor decline and disease duration. Psychiatric symptoms seem more severe for HDL2 patients in the early stages of the disease.

Objectives: Huntington's Disease Like-2 (HDL2) is a rare autosomal dominant genetic disease caused by a mutation in the JPH3 gene. The Huntington's Disease (HD) phenocopy has the greatest clinical resemblance to HD, but its neurocognitive characterisation is poorly researched. This study reports on the neurocognitive profile of seven HDL2 patients including preserved functions, deficits and dissociations (classical and strong) and provides a general characterisation of the cognitive dysfunction of HDL2 in relation to the progression of the disease., Methods: The neuropsychological performance of seven HDL2 patients were compared to one of four control groups, matched by age and level of education using a Single Case-Control design. All patients were polyglots and with public education (primary and secondary). Deficits, as well as classical and strong dissociations within each case profile, were identified by implementing Crawford and Howell's (1998) t-test and the Revised Standardized Difference Test (Crawford and Garthwaite, 2005), respectively., Results: The HDL2 neurocognitive syndrome is heterogeneous with a variable rate of progression, with the psychomotor and dexterity domain consistently and severely impaired., Conclusion: HDL2 has a heterogeneous impact on cognitive functions from early stages in the disease, which evolve to dementia in a non-uniform manner, in keeping with preferential damage in the cerebrocortical-basal ganglia-thalamus-cerebrocortical circuit., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Background: Movement disorders including hemichorea-hemiballism as the initial presentation of an acute ischemic stroke are uncommon. Structures outside of the deep subcortical areas such as the subthalamic nucleus or basal ganglia are rarely involved., Case Report: We report a case of a 72-year-old man with vascular risk factors who presented with acute onset right-sided hemichorea-hemiballism. Metabolic-, infectious-, and toxic-related conditions were ruled out, his EEG was without epileptiform changes. An MRI confirmed an acute ischemic stroke in the parieto-occipital region without any subcortical structures involved. Atrial Fibrillation was later discovered during his hospitalization and was treated appropriately., Conclusions: Although rare, strokes outside of the subthalamic nucleus can result in hemichorea-hemiballism., (Published by Elsevier Inc.)

Thalamotomy is an established treatment for medically refractory tremor. Major complications of thalamotomy include cognitive disturbance, paralysis, dysphagia, sensory loss, and speech disturbance. Hemiballism is a rare complication after thalamotomy. We herein present a 74-year-old female patient who developed choreo-ballistic movement after thalamotomy. She was diagnosed with Lewy body dementia at the age of 70 years and exhibited worsening bilateral hand tremor. Her tremor was severe and pharmacoresistant. Left thalamotomy was planned with the trajectory passing through the ventralis intermedius (VIM) nucleus to the posterior subthalamic area (PSA). The right VIM nucleus and PSA were both coagulated with one trajectory, resulting in the immediate amelioration of right hand tremor. However, four days after surgery, choreo-ballistic movement appeared in the right leg and persisted for six months. Furthermore, tremor recurred after one month. Postoperative MRI showed a small coagulated lesion in the subthalamic nucleus. Although choreo-ballistic movement is a rare complication, it needs to be considered, particularly in patients in which the inferior border of the VIM nucleus is targeted., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Rationale: Hemichorea-hemiballism, a rare manifestation of non-ketotic hyperglycemia, characterized by involuntary arrhythmic motions involving one side of the body, results from focal lesions in the contralateral caudate nucleus and putamen. Hyperkinetic disorders can be complications of uncontrolled diabetes mellitus and should not be ignored., Patient Concerns: We present the case of a 39-year-old woman who presented to the emergency department with a 3-day history of left-sided hemichorea-hemiballism. She had type 2 diabetes mellitus with poor control and maintenance of regular hemodialysis., Diagnoses: The patient was diagnosed as hyperglycemia, normal ketone body and hemichorea-hemiballism based on laboratory examination, computed tomography (CT) scan, and brain magnetic resonance image (MRI)., Interventions: Intensive glycemic control via insulin injection was prescribed for correction of hyperglycemia., Outcomes: The unilateral involuntary movements subsided progressively over four weeks. The patient's hemichorea had completely resolved at the three-month follow-up., Lessons: This unusual clinical presentation is often accompanied by severe hyperglycemia. Appropriate blood glycemic control is important. If physicians recognize and provide early treatment for this disease, it is usually treatable and has a good prognosis.

Background: Sydenham's chorea is the most common acquired movement disorder of adolescence. This clinical manifestation of acute rheumatic fever has a clear and documented relationship with Group A streptococcal infections. The symptoms are involuntary choreiform movements that can affect the face and all extremities. The pathophysiology remains unclear., Case Report: A 12-year-old female was brought to the emergency department with a 2-week history of involuntary muscle spasms of her right arm and leg. Her parents reported intermittent slurred speech and difficulty grasping utensils. Physical examination revealed an awake, alert, age-appropriate female with normal cranial nerves. Patient was found to have choreoathetoid movements on the right extremities with dystonia of right leg with ambulation. Neurology consultation, computed tomography of the head, and magnetic resonance imaging of the brain did not show any acute pathology. Echocardiogram did show mild tricuspid regurgitation, suggestive of rheumatic fever. Anti-streptolysin O titer was markedly elevated, along with DNAse-B antibodies. The patient had marked improvement of movement disorder at just over 1 week later. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Sydenham's chorea is a rare but important movement disorder often related to Group A streptococcus and rheumatic fever. The incidence of rheumatic fever has been decreasing in North America but continues to be much more prevalent in developing countries as well as immigrant populations. This diagnosis is rare and can occasionally be misdiagnosed as a "fidgety" child or as a psychiatric manifestation. Sydenham's chorea is important to diagnose because acute treatment and prophylactic antibiotics can help improve symptoms and minimize cardiac damage., (Copyright © 2019 Elsevier Inc. All rights reserved.)

The term "cerebral palsy mimic" is used to describe a number of neurogenetic disorders that may present with motor symptoms in early childhood, resulting in a misdiagnosis of cerebral palsy. Cerebral palsy describes a heterogeneous group of neurodevelopmental disorders characterized by onset in infancy or early childhood of motor symptoms (including hypotonia, spasticity, dystonia, and chorea), often accompanied by developmental delay. The primary etiology of a cerebral palsy syndrome should always be identified if possible. This is particularly important in the case of genetic or metabolic disorders that have specific disease-modifying treatment. In this article, we discuss clinical features that should alert the clinician to the possibility of a cerebral palsy mimic, provide a practical framework for selecting and interpreting neuroimaging, biochemical, and genetic investigations, and highlight selected conditions that may present with predominant spasticity, dystonia/chorea, and ataxia. Making a precise diagnosis of a genetic disorder has important implications for treatment, and for advising the family regarding prognosis and genetic counseling. © 2019 International Parkinson and Movement Disorder Society., (© 2019 International Parkinson and Movement Disorder Society.)

There are several hundred single-gene disorders that we classify as inborn errors of metabolism. Inborn errors of metabolism are often rare and highly heterogeneous multisystem diseases with non-neurological and neurological manifestations, commonly with onset during childhood. Movement disorders are among the most common neurological problems in inborn errors of metabolism, but, in many cases, remain poorly defined. Although movement disorders are usually not the only and often not the presenting symptom, their recognition can facilitate a diagnosis. Movement disorders contribute substantially to the morbidity in inborn errors of metabolism and can have a significant impact on quality of life. Common metabolic movement disorders include the monoamine neurotransmitter disorders, disorders of amino and organic acid metabolism, metal storage disorders, lysosomal storage disorders, congenital disorders of autophagy, disorders of creatine metabolism, vitamin-responsive disorders, and disorders of energy metabolism. Importantly, disease-modifying therapies exist for a number of inborn errors of metabolism, and early recognition and treatment can prevent irreversible CNS damage and reduce morbidity and mortality. A phenomenology-based approach, based on the predominant movement disorder, can facilitate a differential diagnosis and can guide biochemical, molecular, and imaging testing. The complexity of metabolic movement disorders demands an interdisciplinary approach and close collaboration of pediatric neurologists, neurologists, geneticists, and experts in metabolism. In this review, we develop a general framework for a phenomenology-based approach to movement disorders in inborn errors of metabolism and discuss an approach to identifying the "top ten" of treatable inborn errors of metabolism that present with movement disorders-diagnoses that should never be missed. © 2018 International Parkinson and Movement Disorder Society., (© 2018 International Parkinson and Movement Disorder Society.)

Introduction: Although focal motor seizures may resemble one or more movement disorders their phenomenology and prevalence remain uncertain., Methods: To examine the extent to which focal motor seizures can present with a phenomenology fulfilling diagnostic criteria for movement disorders, 100 consecutive patients with focal motor seizures were rated by movement disorders experts, epileptologists, and general neurologists., Results: A focal motor seizure phenomenologically manifested as a defined movement disorder in 29% of the patients from a consecutive video-EEG documented cohort as per consensus among experts: myoclonus and dystonia (10 and 9 cases, respectively) were the most common movement disorders, followed by chorea (4), stereotypies (3) myoclonus-dystonia (2), and tremor (1)., Conclusions: Movement disorders and focal motor epilepsy share overlapping movement phenomenology., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

GNAO1 variants were recently discovered as causes of epileptic encephalopathies and heterogeneous syndromes presenting with movement disorders (MDs), whose phenomenology and clinical course are yet undefined. We herein focused on GNAO1-related MD, providing an analytical review of existing data to outline the main MD phenomenology and management, clinical evolution and genotype-phenotype correlations. Reviewing 41 previously published patients and assessing 5 novel cases, a comprehensive cohort of 46 patients was analyzed, reassuming knowledge about genotypes, phenotypes, disease course and treatment of this condition. GNAO1-related MD consisted of a severe early-onset hyperkinetic syndrome, with prominent chorea, dystonia and orofacial dyskinesia. Symptoms are poorly responsive to medical therapy and fluctuate, with critical and life-threatening exacerbations, such as status dystonicus. The presence of a choreiform MD appears to be predictive of a higher risk of movement disorder emergency. Surgical treatments are sometimes effective, although severe disabilities persist. Differently from the early infantile epileptic encephalopathy phenotype (associated with loss of function variants), no clear correlation between genotype and MD phenotype emerged, although some variants recurred more frequently, mainly affecting exons 6 and 7., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Background: The frequency of late-onset Huntington's disease (>59 years) is assumed to be low and the clinical course milder. However, previous literature on late-onset disease is scarce and inconclusive., Objective: Our aim is to study clinical characteristics of late-onset compared to common-onset HD patients in a large cohort of HD patients from the Registry database., Methods: Participants with late- and common-onset (30-50 years)were compared for first clinical symptoms, disease progression, CAG repeat size and family history. Participants with a missing CAG repeat size, a repeat size of ≤35 or a UHDRS motor score of ≤5 were excluded., Results: Of 6007 eligible participants, 687 had late-onset (11.4%) and 3216 (53.5%) common-onset HD. Late-onset (n = 577) had significantly more gait and balance problems as first symptom compared to common-onset (n = 2408) (P < .001). Overall motor and cognitive performance (P < .001) were worse, however only disease motor progression was slower (coefficient, -0.58; SE 0.16; P < .001) compared to the common-onset group. Repeat size was significantly lower in the late-onset (n = 40.8; SD 1.6) compared to common-onset (n = 44.4; SD 2.8) (P < .001). Fewer late-onset patients (n = 451) had a positive family history compared to common-onset (n = 2940) (P < .001)., Conclusions: Late-onset patients present more frequently with gait and balance problems as first symptom, and disease progression is not milder compared to common-onset HD patients apart from motor progression. The family history is likely to be negative, which might make diagnosing HD more difficult in this population. However, the balance and gait problems might be helpful in diagnosing HD in elderly patients., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Background: Mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes, the most common maternally inherited mitochondrial disease, can present with a wide range of neurological manifestations including both central and peripheral nervous system involvement. The most frequent genetic mutation reported in mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes syndrome is A3243G in MT-TL1 gene. Stroke-like episodes, dementia, epilepsy, lactic acidemia, myopathy, recurrent headaches, hearing impairment, diabetes, and short stature constitute the known presentations in this syndrome. Among the abnormal involuntary movements in mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes syndrome, myoclonus is the commonest. Other movement disorders, including chorea, are rarely reported in this disorder., Case Presentation: A 14-year-old South Asian boy from rural Bengal (India), born of a second degree consanguineous marriage, with normal birth and development history, presented with abnormal brief jerky movements involving his trunk and limbs, with recurrent falls for 10 months. We present here a case of heteroplasmic mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes syndrome with A3251G mutation, in which the clinical picture was dominated by a host of involuntary abnormal movements including chorea-ballism, myoclonus, and oromandibular dystonia in a backdrop of cognitive decline, seizure, and stroke-like episode. A final diagnosis was established by muscle biopsy and genetic study. Haloperidol was administered to control the involuntary movements along with introduction of co-enzyme Q, besides symptomatic management for his focal seizures. Six months into follow-up his seizures and abnormal movements were controlled significantly with slight improvement of cognitive abilities., Conclusion: The dominance of hyperkinetic movements in the clinical scenario and the finding of a point mutation A3251G in MT-TL1 gene make this a rare presentation.

Huntington's disease (HD) is usually characterized by involuntary hyperkinetic movements, called chorea. The intensity of chorea exhibits a peak in middle stages of HD and then decreases as HD progresses. In contrast, Pakinsonian signs of HD are often less appreciated. They typically progress in a fairly linear pattern over time. In fact, bradykinesia is detectable early on in premanifest gene carriers up to two decades prior to the clinical manifestation of HD symptoms using quantitative motor (Q-Motor) assessments such as finger tapping (digitomotography). Other Parkinsonian symptoms besides bradykinesia are rigidity and postural instability. They typically results in falls and injuries in advanced stages of HD. A primarily Parkinsonian motor phenotype, often seen with little to no chorea, is characteristically observed in older, late manifesting patients and in pediatric HD subjects. Establishing a diagnosis of HD is difficult in these groups and patients are often misdiagnosed in early stages., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Neuroacanthocytosis (NA) syndromes are a group of rare diseases characterized by neurological disorders and misshaped spiky red blood cells (acanthocytes) including Chorea-Acanthocytosis (ChAc), McLeod syndrome (MLS), Huntington disease-like 2 (HDL 2), pantothenate kinase-associated neurodegeneration (PKAN), abeta- and hypobetalipoproteinemia and aceruloplasminemia. This clinically and genetically heterogeneous group of diseases shares main clinical features presenting most often as a hyperkinetic movement disorder. Even though these are long noted disease conditions, we still know only little on the underlying disease mechanisms. The current review focuses upon ChAc as the core entity of NA syndromes caused by mutations in the VPS13A gene. The support of patient organizations and the ERA-NET initiative yielded to different multidisciplinary efforts with significant progress on our understanding of ChAc. Disturbances in two pathways are currently considered to be significantly involved in the pathophysiology of ChAc, namely elevated Lyn kinase phosphorylation and decreased signaling via Phosphoinositide 3-kinase (PI3K). These recent developments may reveal potential drugable targets for causative therapies of ChAc., (Copyright © 2017 Elsevier Masson SAS. All rights reserved.)

Background: While opioid-induced myoclonus is well described, there are limited reports of opioid-induced chorea. Here we present the first case of chorea as a manifestation of opioid neurotoxicity due to hydromorphone., Case Presentation: A 20-year-old woman presenting with fevers and cutaneous lesions was diagnosed with hemophagocytic lymphohistiocytosis secondary to primary cutaneous lymphoma. Surgical resection of a cutaneous lesion was complicated by severe postoperative pain requiring rapid opioid dose escalation. Seven days after hydromorphone was initiated, she developed positive myoclonus, hallucinations, delirium, and involuntary, flowing movements consistent with chorea. She had no personal or family history of nervous system disorders and was not taking any medications associated with drug-induced chorea. Case management: The remainder of her neurologic examination was unremarkable. Her renal function was normal and no etiology was found on neuroimaging or laboratory workup. Hydromorphone was discontinued and pain control was achieved with fentanyl. Case outcome: The patient's neurotoxic symptoms including chorea resolved within 72 h of hydromorphone discontinuation., Conclusion: Further studies are needed to determine which patients have a unique sensitivity to opioids predisposing them to chorea. Clinicians should be aware that chorea may be a sign of such toxicity so that rapid corrective action can be taken.

Purpose of Review: This review will discuss the expanding clinical spectrum of paroxysmal movement disorders and therapeutic options in light of emerging genotypic heterogeneity in these conditions., Recent Findings: Paroxysmal movement disorders comprise a heterogeneous group of rare neurological conditions characterized by intermittent episodes of abnormal movement associated with various triggers. As the clinical and genotypic spectrum of these disorders evolves, so also has the range of therapeutic options. Triheptanoin has recently been shown to be a very promising alternative to the ketogenic diet in paroxysmal exercise-induced dyskinesia. Four-aminopyridine is now considered first-line symptomatic therapy for episodic ataxia type-2, with pre-clinical findings indicating cerebellar neuroprotection., Summary: In light of the newly emerging therapies, careful clinical phenotyping is needed to ensure diagnostic precision and timely initiation of appropriate therapies.

An 83-year-old woman presented with acute-onset haemichorea and haemiballism particularly affecting the left side of the body. She was known to have type 2 diabetes, which was poorly controlled with sitagliptin. She was hyperglycaemic but not ketotic or acidotic. After she was started on insulin and good glycaemic control was achieved, her abnormal movements dramatically improved. MRI of the brain showed a T1-weighted hyperintense lesion on the right basal ganglia, which is typical of chorea-hyperglycaemia-basal ganglia syndrome. Other causes of chorea, for example, Huntington's disease, Sydenham chorea, Wilson's disease, malignancy, systemic lupus erythematosus, haemorrhage/infarction, thyroid dysfunction, drug-induced chorea and antiphospholipid syndrome, were excluded or deemed less likely given her rapid response to achieving near euglycaemia., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Objective: To investigate the cause of the motor asymmetry in Wilson's disease (WD) patients using functional MRI., Methods: Fifty patients with WD and 20 age-matched healthy controls were enrolled. Neurological symptoms were scored using the modified Young Scale. All study subjects underwent diffusion tensor imaging (DTI), susceptibility-weighted imaging (SWI), and resting-state functional MRI (rs-fMRI) of the brain. Six regions of interest (ROI) were chosen. Fiber volumes between ROIs on DTI, corrected phase (CP) values on SWI, amplitude of low-frequency fluctuation (ALFF), and regional homogeneity (REHO) values on rs-fMRI were determined. Asymmetry index (right or left value/left or right value) was evaluated., Results: Asymmetry of rigidity, tremor, choreic movement, and gait abnormality (asymmetry index = 1.33, 1.39, 1.36, 1.40), fiber tracts between the GP and substantia nigra (SN), GP and PU, SN and thalamus (TH), SN and cerebellum, head of the caudate nucleus (CA) and SN, PU and CA, CA and TH, TH and cerebellum (asymmetry index = 1.233, 1.260, 1.269, 1.437, 1.503, 1.138, 1.145, 1.279), CP values in the TH, SN (asymmetry index = 1.327, 1.166), ALFF values, and REHO values of the TH (asymmetry index = 1.192, 1.233) were found. Positive correlation between asymmetry index of rigidity and fiber volumes between the GP and SN, SN and TH ( r  = .221, .133, p  = .043, .036), and tremor and fiber volumes between the CA and TH ( r  = .045, p  = .040) was found., Conclusions: The neurological symptoms of patients with WD were asymmetry. The asymmetry of fiber projections may be the main cause of motor asymmetry in patients with WD.

Benign hereditary chorea (BHC) is a rare autosomal dominant disease that is characterized by non-progressive chorea with early-childhood-onset, congenital hypothyroidism, and neonatal respiratory distress. Although tetrabenazine and levodopa are partly effective for chorea and drop attacks in some patients, there is no standard treatment option. We herein describe a childhood case of BHC that presented with l-thyroxine-responsive drop attacks. A genetic analysis revealed an interstitial deletion that included two enhancer regions of NKX2-1, providing genetic confirmation of BHC. This is the first report to inform the connection between thyroid function and drop attacks in BHC. Moreover, our findings identify l-thyroxine as a therapeutic option for the management of drop attacks in BHC., (Copyright © 2017 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.)