Repeat length in spinocerebellar ataxia type 4 (SCA4) predicts age at onset and disease severity.

Background: Recently, an exonic GGC repeat expansion (RE) was identified by long-read genome sequencing in the ZFHX3 gen, causing spinocerebellar ataxia type 4 (SCA4), a dominant form of ataxia with sensory neuropathy. However, the analysis of larger cohorts of patients remained demanding, resulting in a challenge to diagnose patients and leaving the question of anticipation in SCA4 unanswered.

Objectives: We aimed to develop a GGC repeat test for clinical SCA4 screening and to apply this test to screen two large German SCA pedigrees and samples of unrelated patients collected over the last 25 years.

The Expanding Phenotypical Spectrum of -Related Disorder: Four Novel Cases with a Common Recurrent Variant.

Biallelic variants in the mitochondrial form of the tryptophanyl-tRNA synthetases () can cause a neurodevelopmental disorder with movement disorders including early-onset tremor-parkinsonism syndrome. Here, we describe four new patients, who all presented at a young age with a tremor-parkinsonism syndrome and responded well to levodopa. All patients carry the same recurrent, hypomorphic missense variant (NM_015836.

Not to Miss: Intronic Variants, Treatment, and Review of the Phenotypic Spectrum in -Related Disorder.

is one of four human homologs of the gene (). Biallelic pathogenic variants in the gene are associated with spastic ataxia or spastic paraplegia. Here, we report two patients with intronic pathogenic variants: one patient with early onset severe spastic ataxia and debilitating tremor, which is compound-heterozygous for a canonical (NM_018156.

Cerebellar transcranial current stimulation - An intraindividual comparison of different techniques.

Transcranial current stimulation (tCS) techniques have been shown to induce cortical plasticity. As an important relay in the motor system, the cerebellum is an interesting target for plasticity induction using tCS, aiming to modulate its excitability and connectivity. However, until now it remains unclear, which is the most effective tCS method for inducing plasticity in the cerebellum.

Time estimation and arousal responses in dopa-responsive dystonia.

Dopa-responsive dystonia (DRD) is caused by an impaired dopamine biosynthesis due to a GTP-cyclohydrolase-1 (GCH1) deficiency, resulting in a combination of dystonia and parkinsonism. However, the effect of GCH1 mutations and levodopa treatment on motor control beyond simple movements, such as timing, action preparation and feedback processing, have not been investigated so far. In an active time estimation task with trial-by-trial feedback, participants indicated a target interval (1200 ms) by a motor response.

De Novo and Dominantly Inherited SPTAN1 Mutations Cause Spastic Paraplegia and Cerebellar Ataxia.

Background: Pathogenic variants in SPTAN1 have been linked to a remarkably broad phenotypical spectrum. Clinical presentations include epileptic syndromes, intellectual disability, and hereditary motor neuropathy.

Objectives: We investigated the role of SPTAN1 variants in rare neurological disorders such as ataxia and spastic paraplegia.

Subthalamic nucleus conditioning reduces premotor-motor interaction in Parkinson's disease.

Background: Deep brain stimulation of the subthalamic nucleus is effective to alleviate motor symptoms in advanced Parkinson's disease. Using a novel conditioning paradigm, it has been shown that deep brain stimulation pulses from electrodes in the subthalamic nucleus modulate corticospinal excitability as determined with transcranial magnetic stimulation applied to the motor cortex. The mechanism of action is unclear.

Longitudinal evaluations of somatosensory-motor inhibition in Dopa-responsive dystonia.

Introduction: GCH1 mutations have been linked to decreased striatal dopamine and development of dopa-responsive dystonia (DRD) and Parkinsonism. Sensory and sensorimotor integration impairments have been documented in various forms of dystonia. DRD patients with confirmed GCH1 mutations have demonstrated normal short-latency afferent inhibition (SAI), a measure of sensorimotor inhibition, under chronic dopaminergic replacement therapy (DRT), but reduced inhibition after a single l-dopa dose following 24 h withdrawal.

Relationship of Genotype, Phenotype, and Treatment in Dopa-Responsive Dystonia: MDSGene Review.

Background: Pathogenic variants in 5 genes (GCH1, TH, PTS, SPR, and QDPR), involved in dopamine/tetrahydrobiopterin biosynthesis or recycling, have been linked to Dopa-responsive dystonia (DRD). Diagnosis and treatment are often delayed due to high between- and within-group variability.

Objectives: Comprehensively analyzed individual genotype, phenotype, treatment response, and biochemistry information.

NPTX1 mutations trigger endoplasmic reticulum stress and cause autosomal dominant cerebellar ataxia.

With more than 40 causative genes identified so far, autosomal dominant cerebellar ataxias exhibit a remarkable genetic heterogeneity. Yet, half the patients are lacking a molecular diagnosis. In a large family with nine sampled affected members, we performed exome sequencing combined with whole-genome linkage analysis.

Ventral Telencephalic Patterning Protocols for Induced Pluripotent Stem Cells.

The differentiation of human induced pluripotent stem cells (hiPSCs) into specific cell types for disease modeling and restorative therapies is a key research agenda and offers the possibility to obtain patient-specific cells of interest for a wide range of diseases. Basal forebrain cholinergic neurons (BFCNs) play a particular role in the pathophysiology of Alzheimer's dementia and isolated dystonias. In this work, various directed differentiation protocols based on monolayer neural induction were tested for their effectiveness in promoting a ventral telencephalic phenotype and generating BFCN.

Cerebellar rTMS and PAS effectively induce cerebellar plasticity.

Non-invasive brain stimulation techniques including repetitive transcranial magnetic stimulation (rTMS), continuous theta-burst stimulation (cTBS), paired associative stimulation (PAS), and transcranial direct current stimulation (tDCS) have been applied over the cerebellum to induce plasticity and gain insights into the interaction of the cerebellum with neo-cortical structures including the motor cortex. We compared the effects of 1 Hz rTMS, cTBS, PAS and tDCS given over the cerebellum on motor cortical excitability and interactions between the cerebellum and dorsal premotor cortex / primary motor cortex in two within subject designs in healthy controls. In experiment 1, rTMS, cTBS, PAS, and tDCS were applied over the cerebellum in 20 healthy subjects.

EIF2AK2 Missense Variants Associated with Early Onset Generalized Dystonia.

Objective: The study was undertaken to identify a monogenic cause of early onset, generalized dystonia.

Methods: Methods consisted of genome-wide linkage analysis, exome and Sanger sequencing, clinical neurological examination, brain magnetic resonance imaging, and protein expression studies in skin fibroblasts from patients.

Results: We identified a heterozygous variant, c.

Expanding Data Collection for the MDSGene Database: X-linked Dystonia-Parkinsonism as Use Case Example.

MDSGene is an online database on movement disorders that collates genetic and clinical knowledge using a standardized published literature abstraction strategy. This review is dedicated to X-linked dystonia-parkinsonism (XDP). We screened 233 citations and curated phenotypic and genotypic data for 414 cases.

Somatosensory-motor cortex interactions measured using dual-site transcranial magnetic stimulation.

Background: Dual-site transcranial magnetic stimulation (ds-TMS) is a neurophysiological technique to measure functional connectivity between cortical areas.

Objective/hypothesis: To date, no study has used ds-TMS to investigate short intra-hemispheric interactions between the somatosensory areas and primary motor cortex (M1).

Methods: We examined somatosensory-M1 interactions in the left hemisphere in six experiments using ds-TMS.

Adherent vs. Free-Floating Neural Induction by Dual SMAD Inhibition for Neurosphere Cultures Derived from Human Induced Pluripotent Stem Cells.

Keeping neural stem cells under proliferation, followed by terminal differentiation, can substantially increase the number of neurons generated. With regard to the usability of proliferating neurospheres (NSPHs) cultures, adherent induction protocols have not yet been studied in comparison to embryoid body (EB)-based protocols. To compare these proctocols, neural induction of human induced pluripotent stem cells was performed by dual SMAD inhibition under both adherent and free-floating EB culture conditions.

Plasmid-Based Generation of Induced Neural Stem Cells from Adult Human Fibroblasts.

Direct reprogramming from somatic to neural cell types has become an alternative to induced pluripotent stem cells. Most protocols employ viral expression systems, posing the risk of random genomic integration. Recent developments led to plasmid-based protocols, lowering this risk.