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Alessandro Capuano,1 Giacomo Garone,1,2 Giuseppe Tiralongo,1 Federica Graziola1 1Movement Disorders Clinic, Department of Neuroscience and Neurorehabilitation, IRCCS Bambino Gesù Children’s Hospital, Rome, Italy; 2University Hospital Pediatric Department, IRCCS Bambino Gesù Children’s Hospital, University of Rome Tor Vergata, Rome, ItalyCorrespondence: Alessandro CapuanoMovement Disorders Clinic, Department of Neuroscience and Neurorehabilitation, IRCCS Bambino Gesù Children’s Hospital, Viale Di San Paolo, Rome 15 – 00153, ItalyTel +39 066 859 4092Email alessandro.capuano@opbg.netAbstract: Alternating hemiplegia of childhood (AHC) is a rare neurological disorder affecting children with an onset before 18 months. Diagnostic clues include transient episodes of hemiplegia alternating in the laterality or quadriparesis, nystagmus and other paroxysmal attacks as tonic and dystonic spells. Epilepsy is also a common feature. In the past, a great effort has been done to understand the genetic basis of the disease leading to the discovery of mutations in the ATP1A3 gene encoding for the alpha3 subunit of Na+/K+ATPase, a protein already related to another disease named Rapid Onset Dystonia Parkinsonism (RDP). ATP1A3 mutations account for more than 70% of cases of AHC. In particular, three hotspot mutations account for about 60% of all cases, and these data have been confirmed in large population studies. Specifically, the p.Asp801Asn variant has been found to cause 30– 43% of all cases, p.Glu815Lys is responsible for 16– 35% of cases and p.Gly947Arg accounts for 8– 15%. These three mutations are associated with different clinical phenotype in terms of symptoms, severity and prognosis. In vitro and in vivo models reveal that a crucial role of Na+/K+ATPase pump activity emerges in maintaining a correct membrane potential, survival and homeostasis of neurons. Herein, we attempt to summarize all clinical, genetic and molecular aspects of AHC considering ATP1A3 as its primary disease-causing determinant.Keywords: ATP1A3, Na+/K+ATPase, AHC, genetics, animal models

Background: GNAO1 -related disorders ( GNAO1 -RD) encompass a diverse spectrum of neurodevelopmental and movement disorders arising from variants in the GNAO1 gene. Dyskinetic crises, marked by sudden and intense exacerbations of abnormal involuntary movements, present a significant challenge in GNAO1 -RD., Objectives: This study aimed to establish a standardized framework for understanding dyskinetic crises, addressing crucial aspects such as definition, triggers, diagnostic criteria, complications, and management strategies., Methods: A Delphi consensus process was conducted involving international experts in GNAO1 -RD. The panel of thirteen experts participated in three voting rounds, discussing 90 statements generated through a literature review and clinical expertise., Results: Consensus was achieved on 31 statements, defining dyskinetic crises as abrupt, paroxysmal episodes involving distinct abnormal movements in multiple body regions, triggered by emotional stress or infections. Dyskinetic crises may lead to functional impairment and complications, emphasizing the need for prompt recognition. While individualized pharmacological recommendations were not provided, benzodiazepines and clonidine were suggested for acute crisis management. Chronic treatment options included tetrabenazine, benzodiazepines, gabapentin, and clonidine. Deep brain stimulation should be considered early in the treatment of refractory or prolonged dyskinetic crisis., Conclusion: This consensus provides a foundation for understanding and managing dyskinetic crises in GNAO1 -RD for clinicians, caregivers, and researchers. The study emphasizes the importance of targeted parental and caregiver education, which enables early recognition and intervention, thereby potentially minimizing both short- and long-term complications. Future research should concentrate on differentiating dyskinetic crises from other neurological events and investigating potential risk factors that influence their occurrence and nature. The proposed standardized framework improves clinical management, stakeholder communication, and future GNAO1 -RD research., Competing Interests: 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 © 2024 Domínguez Carral, Reinhard, Ebrahimi-Fakhari, Dorison, Galosi, Garone, Malenica, Ravelli, Serdaroglu, van de Pol, Koy, Leuzzi, Roubertie, Lin, Doummar, Cif and Ortigoza-Escobar.)

Background: To date, the etiology and risk factors of torticollis are still poorly defined in the pediatric literature. Especially in the Emergency Department (ED) scenario, it is critical to reliably distinguish benign and transient conditions from (potentially) life-threatening disorders. This study describes the clinical characteristics of a large sample of children with torticollis. The aim of our study was to detect epidemiology, etiology and predictive variables associated with a higher risk of life-threatening conditions in acute torticollis., Methods: We conducted a pediatric retrospective study of acute torticollis over a 13-year period referred to the ED of a tertiary pediatric Hospital. We reported the characteristics in the overall sample and in two subgroups divided according to urgency of the underlying condition. Furthermore, we developed a multivariate model aimed at identifying the main clinical predictors of the need for urgent care., Results: 1409 patients were analyzed (median age 5.7 years, IQR 5.8). A history of trauma was present in 393 patients (27.9%). The symptom most frequently associated with torticollis were pain (83.5%). At least one pathological finding was found in 5.4 to 7.9% of patients undergoing further imaging. Hospitalization was required in 11.1% of cases (median duration 4 days). The most frequent etiologies of torticollis were postural cause (43.1%), traumatic (29.5%), and infective/inflammatory (19.1%). A longer time from onset of torticollis and the presence of headache or vomiting were strongly correlated with an underlying urgent condition, after adjusting for the other clinically and statistically significant variables in the bivariate analysis., Conclusion: Our study shows that an urgent condition most commonly occur in patients presenting with history of trauma or headache, vomiting and torticollis for more than 24 h should undergo further diagnostic evaluation and short-term follow-up, restricting invasive or expensive investigations to patients with clinical suspicion of an underlying harmful condition., (© 2024. The Author(s).)

(1) Background: Cockayne syndrome (CS) is an ultra-rare multisystem disorder, classically subdivided into three forms and characterized by a clinical spectrum without a clear genotype-phenotype correlation for both the two causative genes ERCC6 (CS type B) and ERCC8 (CS type A). We assessed this, presenting a series of patients with genetically confirmed CSB. (2) Materials and Methods: We retrospectively collected demographic, clinical, genetic, neuroimaging, and serum neurofilament light-chain (sNFL) data about CSB patients; diagnostic and severity scores were also determined. (3) Results: Data of eight ERCC6/ CSB patients are presented. Four patients had CS I, three patients CS II, and one patient CS III. Various degrees of ataxia and spasticity were cardinal neurologic features, with variably combined systemic characteristics. Mean age at diagnosis was lower in the type II form, in which classic CS signs were more evident. Interestingly, sNFL determination appeared to reflect clinical classification. Two novel premature stop codon and one novel missense variants were identified. All CS I subjects harbored the p.Arg735Ter variant; the milder CS III subject carried the p.Leu764Ser missense change. (4) Conclusion: Our work confirms clinical variability also in the ERCC6 /CSB type, where manifestations may range from severe involvement with prenatal or neonatal onset to normal psychomotor development followed by progressive ataxia. We propose, for the first time in CS, sNFL as a useful peripheral biomarker, with increased levels compared to currently available reference values and with the potential ability to reflect disease severity.

CTNNB1 [OMIM *116806] encodes β-catenin, an integral part of the cadherin/catenin complex, which functions as effector of Wnt signaling. CTNNB1 is highly expressed in brain as well as in other tissues, including heart. Heterozygous CTNNB1 pathogenic variations are associated with a neurodevelopmental disorder characterized by spastic diplegia and visual defects (NEDSDV) [OMIM #615075], featuring psychomotor delay, intellectual disability, behavioral disturbances, movement disorders, visual defects and subtle facial and somatic features. We report on a new series of 19 NEDSDV patients (mean age 10.3 years), nine of whom bearing novel CTNNB1 variants. Notably, five patients showed congenital heart anomalies including absent pulmonary valve with intact ventricular septum, atrioventricular canal with hypoplastic aortic arch, tetralogy of Fallot, and mitral valve prolapse. We focused on the cardiac phenotype characterizing such cases and reviewed the congenital heart defects in previously reported NEDSDV patients. While congenital heart defects had occasionally been reported so far, the present findings configure a higher rate of cardiac anomalies, suggesting dedicated heart examination to NEDSDV clinical management., (© 2023 The Authors. Clinical Genetics published by John Wiley & Sons Ltd.)

Background: To date, no study has specifically examined children with acute-onset pupillary motility disorders (APMD). Especially in the Emergency Department (ED), it is crucial to distinguish benign and transient conditions from life-threatening or urgent conditions (UCs). The aim of the study is to describe the clinical characteristics of children with APMD and their association with an increased risk of UCs., Methods: We conducted a pediatric retrospective study of APMD referred to ED over a 10-year period. We described the characteristics in the overall sample and in two subgroups divided according to urgency of the underlying condition. Furthermore, we applied a logistic regression model to identify the variables predictive of LT condition., Results: We analyzed 101 patients. In 59.4%, the APMD was isolated. In patients with extra-ocular involvement, the most frequently associated features were altered consciousness, headache, and vomiting. Exposure to toxic agents was reported in 48.5%. Urgent conditions occurred significantly more frequently in older children, presenting bilateral APMD and/or other ocular or extra-ocular manifestations., Conclusions: Our study shows that UCs most commonly occur in patients presenting with bilateral APMD and other associated features. In unilateral/isolated APMD ophthalmological examination, exclusion of toxic exposure and observation until resolution of symptoms should be recommended.

The "Spazio Huntington-A Place for Children" program was launched in 2019. The aim was to contact at risk kids within Huntington disease (HD) families, to provide counseling to their parents and to start a prospective follow-up of kids suspicious to manifest pediatric HD (PHD). We met 25 at risk kids in two years, four of whom with PHD and highly expanded (HE) mutations beyond 80 CAG repeats. We rated motor, neuropsychological and behavioral changes in all PHD kids by the Unified HD Rating Scale (UHDRS)-total motor score (TMS) and additional measures of (1) cognitive level (Leiter International Performance Scale), (2) adaptive functioning (Adaptive Behavior Assessment Systems), (3) receptive language (Peabody Picture Vocabulary Test) and (4) behavioral abnormalities (Child Behavior Check List and Children's Yale-Brown Obsessive Compulsive Scale). All PHD kids showed a severe progression of neurological and psychiatric manifestations including motor, cognitive and behavioral changes. The magnetic resonance imaging contributed to confirm the suspicious clinical observation by highlighting very initial striatum abnormalities in PHD. Spazio Huntington is a program to prospectively study PHD, the most atypical face of HD, and may represent the basis to recruit PHD patients in future clinical trials.

GNAO1 gene mutations are associated with a neurodevelopmental disorder characterized by developmental delay, epilepsy, and movement disorder. Eye tracking and eye movement analysis are an intriguing method to assess cognitive and language function and, to the best of our knowledge, it has never been tested in a standardized way in GNAO1 . GNAO1 children are usually wheelchair-bound and with numerous motor constrains, including dystonic movements and postures, heterotropia, and hypotonia, making the cognitive assessment arduous. These contribute to the burden and disability, with a high level of frustration of caregivers and patients. We have herein demonstrated that, through an eye tracking system, six GNAO1 patients evaluated showed variable degrees of communicative intent through intentionally directed gaze. Moreover, three of these were able to complete a cognitive evaluation, and showed normal fluid intelligence and lexical comprehension. In conclusion, in GNAO1 -related disorders, the degree of cognitive development is underestimated; eye tracking technologies may help in overcome these boundaries.

Acute-onset movement disorders (MDs) are an increasingly recognized neurological emergency in both adults and children. The spectrum of possible causes is wide, and diagnostic work-up is challenging. In their acute presentation, MDs may represent the prominent symptom or an important diagnostic clue in a broader constellation of neurological and extraneurological signs. The diagnostic approach relies on the definition of the overall clinical syndrome and on the recognition of the prominent MD phenomenology. The recognition of the underlying disorder is crucial since many causes are treatable. In this review, we summarize common and uncommon causes of acute-onset movement disorders, focusing on clinical presentation and appropriate diagnostic investigations. Both acquired (immune-mediated, infectious, vascular, toxic, metabolic) and genetic disorders causing acute MDs are reviewed, in order to provide a useful clinician's guide to this expanding field of pediatric neurology.

Aim: To critically analyse the management of status dystonicus and prestatus dystonicus in children and adolescents, in order to examine clinical features, acute management, and risk of relapse in a paediatric cohort., Method: Clinical, demographic, and therapeutic features were analysed according to disease severity. Risk of subsequent relapse was estimated through Kaplan-Meier curves., Results: Thirty-four patients (eight females, 26 males) experiencing 63 episodes of acute dystonia exacerbations at a tertiary referral Italian hospital were identified. Mean age at status dystonicus presentation was 9 years 11 months (11y at inclusion in the study). Onset of dystonia dated back to infancy in most cases. Fourteen patients experienced two or more episodes. Infections were the most common trigger (48%). Benzodiazepines were the most commonly used drugs for acute management. Stereotactic pallidotomy was performed in six cases during status dystonicus, and in two additional patients it was electively performed after medical management. The probability of survival free from status dystonicus relapses was 78% after 4 months and 61% after 27 months., Interpretation: Dystonia exacerbations are potentially life-threating emergencies, with a considerable risk of relapse. Nevertheless, no obvious factors for relapse risk stratification exist. Pallidotomy is a feasible option in medical refractory status dystonicus for patients with limited deep brain stimulation applicability, but the risk of recurrence is elevated., What This Paper Adds: Acute exacerbations may affect up to 10% of children with dystonia. Infections are the most common precipitant factor. In about 30% of the cases, intensive care unit admission is needed. Subsequent relapses are common, reaching 25% risk at 1 year. Pallidotomy can be considered in medical-refractory cases with no deep brain stimulation applicability., (© 2019 Mac Keith Press.)

Paroxysmal movement disorders (PMDs) are rare neurological diseases typically manifesting with intermittent attacks of abnormal involuntary movements. Two main categories of PMDs are recognized based on the phenomenology: Paroxysmal dyskinesias (PxDs) are characterized by transient episodes hyperkinetic movement disorders, while attacks of cerebellar dysfunction are the hallmark of episodic ataxias (EAs). From an etiological point of view, both primary (genetic) and secondary (acquired) causes of PMDs are known. Recognition and diagnosis of PMDs is based on personal and familial medical history, physical examination, detailed reconstruction of ictal phenomenology, neuroimaging, and genetic analysis. Neurophysiological or laboratory tests are reserved for selected cases. Genetic knowledge of PMDs has been largely incremented by the advent of next generation sequencing (NGS) methodologies. The wide number of genes involved in the pathogenesis of PMDs reflects a high complexity of molecular bases of neurotransmission in cerebellar and basal ganglia circuits. In consideration of the broad genetic and phenotypic heterogeneity, a NGS approach by targeted panel for movement disorders, clinical or whole exome sequencing should be preferred, whenever possible, to a single gene approach, in order to increase diagnostic rate. This review is focused on clinical and genetic features of PMDs with the aim to (1) help clinicians to recognize, diagnose and treat patients with PMDs as well as to (2) provide an overview of genes and molecular mechanisms underlying these intriguing neurogenetic disorders., Competing Interests: The authors declare no conflict of interest.

In recent years, genetic techniques of diagnosis have shown rapid development, resulting in a modified clinical approach to many diseases, including neurological disorders. Movement disorders, in particular those arising in childhood, pose a diagnostic challenge. First, from a purely phenomenological point of view, the correct clinical classification of signs and symptoms may be difficult and require expert evaluation. This is because the clinical picture is often a mixture of hyperkinetic and hypokinetic disorders, and within hyperkinetic movement disorders, combined phenotypes are not unusual. Second, although several genes that cause movement disorders in children are now well-known, many of them have only been described in adult populations or discovered in patients after many years of disease. Furthermore, diseases that alter their mechanisms from childhood to adulthood are still little known, and many phenotypes in children are the result of a disruption of normal neurodevelopment. High-throughput gene screening addresses these difficulties and has modified the approach to genetic diagnosis. In the exome-sequencing era, customized genetic panels now offer the ability to perform fast and low-cost screening of the genes commonly involved in the pathogenesis of the disease. Here, we describe a 3-year study using a customized gene panel for pediatric-onset movement disorders in a selected cohort of children and adolescents. We report a satisfying diagnostic yield, further confirming the usefulness of gene panel analysis., (Copyright © 2019 Graziola, Garone, Stregapede, Bosco, Vigevano, Curatolo, Bertini, Travaglini and Capuano.)

Background: Acute ocular motility disorders (OMDs) in children admitted to Emergency Department (ED) represents a not so rare condition with a wide spectrum of different etiologies. The emergency physician must be skilled in rapidly identifying patients with potentially life threatening (LT) forms, requiring further diagnostic procedures. The aim of the study was to assess characteristics of children with acute Ocular Motility Disorders (OMDs), and to identify "red flags" for recognition of underlying life-threatening (LT) conditions., Methods: A retrospective cohort study evaluated children (2 months-17 years) admitted to a tertiary Emergency Department in 2009-2014. A subgroup analysis was performed comparing children with and without LT conditions., Results: Of 192 visits for OMDs, the isolated strabismus occurred most frequently (55.6%), followed by pupil disorders (31.8%), ptosis (5.2%) and combined OMDs (11.5%). The majority of acute OMDs involved no underlying LT conditions (n = 136) and most of them were infants or toddlers (50%). In a multivariable analysis, LT conditions included especially children over 6 years of age, increasing the odds ratio by 2% for each months of age (p = 0.009). LT etiologies were 16 times more likely in combined OMDs (p = 0.018), were over 13 times more likely to report associated extra-ocular signs/symptoms (p = 0.017) and over 50 times more likely to report co-morbidity (p = 0.017)., Conclusion: OMDs are not an uncommon presentation at ED. Although most of them involve non-LT conditions, the ED physician should consider potential "red flags" for appropriate management of children such as age > 6 years, combined OMDs, extra-ocular symptoms and co-morbidity.

Deletions in the 9q33-q34 region have been reported in patients with early onset epileptic encephalopathy, but a consistent phenotype has yet to emerge. We report on the diagnosis of a de novo 9q33-q34.12 microdeletion of 4 Mb in a 15-month-old girl presenting with severe psychomotor delay, facial dysmorphisms, thin corpus callosum and early myoclonic encephalopathy. This deletion encompasses 101 RefSeq genes, including the four autosomal dominant genes STXBP1, SPTAN1, ENG and TOR1A. We discuss genetic, clinical and epileptic features comparing our patient with those previously reported in the literature., (© 2015 John Wiley & Sons Ltd/University College London.)