Methylation assay in KMT2B-related dystonia: a novel diagnostic validation tool.

Background/objectives: KMT2B-related dystonia (DYT28, OMIM #617284) is a progressive neurological condition characterized by early onset movement disorders with autosomal dominant inheritance. In this study, we describe the use of a genome methylation episignature methodology to functionally validate two variants of uncertain significance (VUS) in the KMT2B gene.

Methods: Genome-wide methylation status was assessed using the EPIC methylation assay in peripheral blood samples from two subjects with early onset movement disorder and missense variants of uncertain significance in the KMT2B gene (p.

Gerstmann-Sträussler-Scheinker Disease Presenting as Late-Onset Slowly Progressive Spinocerebellar Ataxia, and Comparative Case Series with Neuropathology.

Background: Genetic prion diseases, including Gerstmann-Sträussler-Scheinker disease (GSS), are extremely rare, fatal neurodegenerative disorders, often associated with progressive ataxia and cognitive/neuropsychiatric symptoms. GSS typically presents as a rapidly progressive cerebellar ataxia, associated with cognitive decline. Late-onset cases are rare.

Scoping Review on ADCY5-Related Movement Disorders.

Background: Adenylyl cyclase 5 (ADCY5)-related movement disorder (ADCY5-RMD) is a rare, childhood-onset disease resulting from pathogenic variants in the gene. The clinical features, diagnostic options, natural history, and treatments for this disease are poorly characterized and have never been established through a structured approach.

Objective: This scoping review attempts to summarize all available clinical literature on ADCY5-RMD.

A framework for individualized splice-switching oligonucleotide therapy.

Splice-switching antisense oligonucleotides (ASOs) could be used to treat a subset of individuals with genetic diseases, but the systematic identification of such individuals remains a challenge. Here we performed whole-genome sequencing analyses to characterize genetic variation in 235 individuals (from 209 families) with ataxia-telangiectasia, a severely debilitating and life-threatening recessive genetic disorder, yielding a complete molecular diagnosis in almost all individuals. We developed a predictive taxonomy to assess the amenability of each individual to splice-switching ASO intervention; 9% and 6% of the individuals had variants that were 'probably' or 'possibly' amenable to ASO splice modulation, respectively.

Phenotypic, molecular, and functional characterization of COQ7-related primary CoQ deficiency: Hypomorphic variants and two distinct disease entities.

Primary coenzyme Q10 (CoQ) deficiency is a group of inborn errors of metabolism caused by defects in CoQ biosynthesis. Biallelic pathogenic variants in COQ7, encoding mitochondrial 5-demethoxyubiquinone hydroxylase, have been reported in nine patients from seven families. We identified five new patients with COQ7-related primary CoQ deficiency, performed clinical assessment of the patients, and studied the functional effects of current and previously reported COQ7 variants and potential treatment options.

Pearls & Oy-sters: Paroxysmal Exercise-Induced Dyskinesias Due to Pyruvate Dehydrogenase Deficiency.

Paroxysmal exercise-induced movement disorders may be caused by energy metabolism disorders, such as Glut 1 deficiency, pyruvate dehydrogenase deficiency, or mitochondrial respiratory chain disorders. A 4-year-old boy with a history of febrile seizures presented with paroxysmal dystonia, triggered by exercise, or occurring at rest. Additional investigations demonstrated pallidal hyperintensities on brain MRI and low CSF glucose.

Functional validation of novel variants in B4GALNT1 associated with early-onset complex hereditary spastic paraplegia with impaired ganglioside synthesis.

Childhood-onset forms of hereditary spastic paraplegia are ultra-rare diseases and often present with complex features. Next-generation-sequencing allows for an accurate diagnosis in many cases but the interpretation of novel variants remains challenging, particularly for missense mutations. Where sufficient knowledge of the protein function and/or downstream pathways exists, functional studies in patient-derived cells can aid the interpretation of molecular findings.

Paroxysmal Genetic Movement Disorders and Epilepsy.

Paroxysmal movement disorders include paroxysmal kinesigenic dyskinesia, paroxysmal non-kinesigenic dyskinesia, paroxysmal exercise-induced dyskinesia, and episodic ataxias. In recent years, there has been renewed interest and recognition of these disorders and their intersection with epilepsy, at the molecular and pathophysiological levels. In this review, we discuss how these distinct phenotypes were constructed from a historical perspective and discuss how they are currently coalescing into established genetic etiologies with extensive pleiotropy, emphasizing clinical phenotyping important for diagnosis and for interpreting results from genetic testing.

Prevalence of -mediated spinocerebellar ataxia in a North American ataxia cohort.

Objective: We evaluated the prevalence of pathogenic repeat expansions in replication factor C subunit 1 () and disabled adaptor protein 1 in an undiagnosed ataxia cohort from North America.

Methods: A cohort of 596 predominantly adult-onset patients with undiagnosed familial or sporadic cerebellar ataxia was evaluated at a tertiary referral ataxia center and excluded for common genetic causes of cerebellar ataxia. Patients were then screened for the presence of pathogenic repeat expansions in (AAGGG) and (ATTTC) using fluorescent repeat-primed PCR (RP-PCR).

Paroxysmal movement disorders - practical update on diagnosis and management.

: Paroxysmal dyskinesias and episodic ataxias are often caused by mutations in genes related to cell membrane and synaptic function. Despite the exponential increase in publications of genetically confirmed cases, management remains largely clinical based on non-systematic evidence. : The authors provide a historical and clinical review of the main types of paroxysmal dyskinesias and episodic ataxias, with recommendations for diagnosis and management of patients suffering from these conditions.

Inherited and Acquired Choreas.

Chorea is a symptom of a broad array of genetic, structural, and metabolic disorders. While chorea can result from systemic illness and damage to diverse brain structures, injury to the basal ganglia, especially the putamen or globus pallidus, appears to be a uniting features of these diverse neuropathologies. The timing of onset, rate of progression, and the associated neurological or systemic symptoms can often narrow the differential diagnosis to a few disorders.

Transition From Pediatric to Adult Neurologic Care.

Purpose Of Review: With advances in medical care, the number of youths surviving with medically complex conditions has been steadily increasing. Inadequate transition planning and execution can lead to gaps in care, unexpected emergency department visits, and an increase in health care costs and patient/caregiver anxiety. Many barriers that prevent adequate transition have been identified, including insufficient time or staff to provide transition services, inadequate reimbursement, resistance from patients and caregivers, and a dearth of accepting adult providers.

The neurologist's role in supporting transition to adult health care: A consensus statement.

The child neurologist has a critical role in planning and coordinating the successful transition from the pediatric to adult health care system for youth with neurologic conditions. Leadership in appropriately planning a youth's transition and in care coordination among health care, educational, vocational, and community services providers may assist in preventing gaps in care, delayed entry into the adult care system, and/or health crises for their adolescent patients. Youth whose neurologic conditions result in cognitive or physical disability and their families may need additional support during this transition, given the legal and financial considerations that may be required.

Dystonia-Causing Mutations as a Contribution to the Etiology of Spasmodic Dysphonia.

Objective: Spasmodic dysphonia is a focal dystonia of the larynx with heterogeneous manifestations and association with familial risk factors. There are scarce data to allow precise understanding of etiology and pathophysiology. Screening for dystonia-causing genetic mutations has the potential to allow accurate diagnosis, inform about genotype-phenotype correlations, and allow a better understanding of mechanisms of disease.