scholarly journals Spinocerebellar ataxias (SCAs) caused by common mutations

Neurogenetics ◽  
2021 ◽  
Author(s):  
Ulrich Müller
Keyword(s):  
Mitochondrial Gene ◽  
Point Mutations ◽  
Signs And Symptoms ◽  
Common Disease ◽  
Disease Genes ◽  
Spinocerebellar Ataxias ◽  
Locus Heterogeneity ◽  
Disease Mechanisms ◽  
Extrapyramidal Signs ◽  
Repeat Expansions

AbstractThe term SCA refers to a phenotypically and genetically heterogeneous group of autosomal dominant spinocerebellar ataxias. Phenotypically they present as gait ataxia frequently in combination with dysarthria and oculomotor problems. Additional signs and symptoms are common and can include various pyramidal and extrapyramidal signs and intellectual impairment. Genetic causes of SCAs are either repeat expansions within disease genes or common mutations (point mutations, deletions, insertions etc.). Frequently the two types of mutations cause indistinguishable phenotypes (locus heterogeneity). This article focuses on SCAs caused by common mutations. It describes phenotype and genotype of the presently 27 types known and discusses the molecular pathogenesis in those 21 types where the disease gene has been identified. Apart from the dominant types, the article also summarizes findings in a variant caused by mutations in a mitochondrial gene. Possible common disease mechanisms are considered based on findings in the various SCAs described.

scholarly journals Mutations in MT-ATP6 are a frequent cause of adult-onset spinocerebellar ataxia

2021 ◽  
Author(s):  
Dagmar Nolte ◽  
Jun-Suk Kang ◽  
Amrei Hofmann ◽  
Eva Schwaab ◽  
Heidrun H. Krämer ◽  
...  
Keyword(s):  
Spinocerebellar Ataxia ◽  
Mitochondrial Gene ◽  
Transmembrane Helix ◽  
Point Mutations ◽  
Gene Mutations ◽  
Nuclear Gene ◽  
Adult Onset ◽  
High Prevalence ◽  
Repeat Expansions ◽  
Sporadic Cases

AbstractAdult-onset ataxias are a genetically and clinically heterogeneous group of movement disorders. In addition to nuclear gene mutations, sequence changes have also been described in the mitochondrial genome. Here, we present findings of mutation analysis of the mitochondrial gene MT-ATP6. We analyzed 94 patients with adult-onset spinocerebellar ataxia (SCA), including 34 sporadic cases. In all patients, common sequence changes found in SCAs such as repeat expansions and point mutations had been excluded previously. We found pathogenic MT-ATP variants in five of these patients (5.32%), two of whom were sporadic. Four of the five mutations have not previously been described in ataxias. All but one of these mutations affect transmembrane helices of subunit-α of ATP synthase. Two mutations (p.G16S, and p.P18S) disrupt transmembrane helix 1 (TMH1), one mutation (p.G167D) affects TMH5, and another one (p.L217P) TMH6. The fifth mutation (p.T96A) describes an amino acid change in close proximity to transmembrane helix 3 (TMH3). The level of heteroplasmy was either complete or very high ranging from 87 to 99%. The high prevalence of pathogenic MT-ATP6 variants suggests that analysis of this gene should be included in the routine workup of both hereditary and sporadic ataxias.

scholarly journals DISC1 regulates N-Methyl-D-Aspartate receptor dynamics: Abnormalities induced by a Disc1 mutation modelling a translocation linked to major mental illness

2018 ◽  
Author(s):  
Elise L.V. Malavasi ◽  
Kyriakos D. Economides ◽  
Ellen Grünewald ◽  
Paraskevi Makedonopoulou ◽  
Philippe Gautier ◽  
...  
Keyword(s):  
Mental Illness ◽  
Synaptic Plasticity ◽  
Large Scale ◽  
Mutant Mouse ◽  
Psychiatric Patients ◽  
Cognitive Disorders ◽  
Copy Number Variant ◽  
Common Disease ◽  
Disease Mechanisms ◽  
Human Neurons

ABSTRACTThe neuromodulatory gene DISC1 is disrupted by a t(1;11) translocation that is highly penetrant for schizophrenia and affective disorders, but how this translocation affects DISC1 function is incompletely understood. N-Methyl-D-Aspartate receptors (NMDAR) play a central role in synaptic plasticity and cognition, and are implicated in the pathophysiology of schizophrenia through genetic and functional studies. We show that the NMDAR subunit GluN2B complexes with DISC1-associated trafficking factor TRAK1, while DISC1 interacts with the GluN1 subunit and regulates dendritic NMDAR motility in cultured mouse neurons. Moreover, in the first mutant mouse that models DISC1 disruption by the translocation, the pool of NMDAR transport vesicles and surface/synaptic NMDAR expression are increased. Since NMDAR cell surface/synaptic expression is tightly regulated to ensure correct function, these changes in the mutant mouse are likely to affect NMDAR signalling and synaptic plasticity. Consistent with these observations, RNASeq analysis of translocation carrier-derived human neurons indicates abnormalities of excitatory synapses and vesicle dynamics. RNASeq analysis of the human neurons also identifies many differentially expressed genes previously highlighted as putative schizophrenia and/or depression risk factors through large-scale genome-wide association and copy number variant studies, indicating that the translocation triggers common disease pathways that are shared with unrelated psychiatric patients. Altogether our findings suggest that translocation-induced disease mechanisms are likely to be relevant to mental illness in general, and that such disease mechanisms include altered NMDAR dynamics and excitatory synapse function. This could contribute to the cognitive disorders displayed by translocation carriers.

scholarly journals Modeling Rare Human Disorders in Mice: The Finnish Disease Heritage

Cells ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 3158
Author(s):  
Tomáš Zárybnický ◽  
Anne Heikkinen ◽  
Salla M. Kangas ◽  
Marika Karikoski ◽  
Guillermo Antonio Martínez-Nieto ◽  
...  
Keyword(s):  
Human Physiology ◽  
Animal Models ◽  
Mouse Models ◽  
Rare Diseases ◽  
Disease Modeling ◽  
Common Disease ◽  
Molecular Pathways ◽  
Finnish Population ◽  
Disease Mechanisms ◽  
Human Disorders

The modification of genes in animal models has evidently and comprehensively improved our knowledge on proteins and signaling pathways in human physiology and pathology. In this review, we discuss almost 40 monogenic rare diseases that are enriched in the Finnish population and defined as the Finnish disease heritage (FDH). We will highlight how gene-modified mouse models have greatly facilitated the understanding of the pathological manifestations of these diseases and how some of the diseases still lack proper models. We urge the establishment of subsequent international consortiums to cooperatively plan and carry out future human disease modeling strategies. Detailed information on disease mechanisms brings along broader understanding of the molecular pathways they act along both parallel and transverse to the proteins affected in rare diseases, therefore also aiding understanding of common disease pathologies.

scholarly journals Ataxias with Autosomal, X-Chromosomal or Maternal Inheritance

2009 ◽  
Vol 36 (4) ◽  
pp. 409-428 ◽  
Author(s):  
Josef Finsterer
Keyword(s):  
Ataxia Telangiectasia ◽  
Large Scale ◽  
Autosomal Recessive ◽  
Autosomal Dominant ◽  
Late Onset ◽  
Fragile X ◽  
Axonal Neuropathy ◽  
Friedreich Ataxia ◽  
Point Mutations ◽  
Spinocerebellar Ataxias

Heredoataxias are a group of genetic disorders with a cerebellar syndrome as the leading clinical manifestation. The current classification distinguishes heredoataxias according to the trait of inheritance into autosomal dominant, autosomal recessive, X-linked, and maternally inherited heredoataxias. The autosomal dominant heredoataxias are separated into spinocerebellar ataxias (SCA1-8, 10-15, 17-23, 25-30, and dentato-rubro-pallido-luysian atrophy), episodic ataxias (EA1-7), and autosomal dominant mitochondrial heredoataxias (Leigh syndrome, MIRAS, ADOAD, and AD-CPEO). The autosomal recessive ataxias are separated into Friedreich ataxia, ataxia due to vitamin E deficiency, ataxia due to Abeta-lipoproteinemia, Refsum disease, late-onset Tay-Sachs disease, cerebrotendineous xanthomatosis, spinocerebellar ataxia with axonal neuropathy, ataxia telangiectasia, ataxia telangiectasia-like disorder, ataxia with oculomotor apraxia 1 and 2, spastic ataxia of Charlevoix-Saguenay, Cayman ataxia, Marinesco-Sjögren syndrome, and autosomal recessive mitochondrial ataxias (AR-CPEO, SANDO, SCAE, AHS, IOSCA, MEMSA, LBSL CoQ-deficiency, PDC-deficiency). Only two of the heredoataxias, fragile X/tremor/ataxia syndrome, and XLSA/A are transmitted via an X-linked trait. Maternally inherited heredoataxias are due to point mutations in genes encoding for tRNAs, rRNAs, respiratory chain subunits or single large scale deletions/duplications of the mitochondrial DNA and include MELAS, MERRF, KSS, PS, MILS, NARP, and non-syndromic mitochondrial disorders. Treatment of heredoataxias is symptomatic and supportive and may have a beneficial effect in single patients.**Please see page 424 for abbreviation list.

scholarly journals Twenty-five years since the identification of the first SCA gene: history, clinical features and perspectives for SCA1

2018 ◽  
Vol 76 (8) ◽  
pp. 555-562 ◽  
Author(s):  
Carlos Roberto Martins Junior ◽  
Fabrício Castro de Borba ◽  
Alberto Rolim Muro Martinez ◽  
Thiago Junqueira Ribeiro de Rezende ◽  
Iscia Lopes Cendes ◽  
...  
Keyword(s):  
Clinical Features ◽  
Autosomal Dominant ◽  
Trinucleotide Repeat ◽  
Point Of View ◽  
Spinocerebellar Ataxias ◽  
Coding Region ◽  
The Past ◽  
Monogenic Diseases ◽  
Repeat Expansions ◽  
Core Features

ABSTRACT Spinocerebellar ataxias (SCA) are a clinically and genetically heterogeneous group of monogenic diseases that share ataxia and autosomal dominant inheritance as the core features. An important proportion of SCAs are caused by CAG trinucleotide repeat expansions in the coding region of different genes. In addition to genetic heterogeneity, clinical features transcend motor symptoms, including cognitive, electrophysiological and imaging aspects. Despite all the progress in the past 25 years, the mechanisms that determine how neuronal death is mediated by these unstable expansions are still unclear. The aim of this article is to review, from an historical point of view, the first CAG-related ataxia to be genetically described: SCA 1.

Inherited Ataxias

2015 ◽  
Author(s):  
Susan Perlman
Keyword(s):  
Autosomal Recessive ◽  
Autosomal Dominant ◽  
Friedreich Ataxia ◽  
Spinocerebellar Ataxias ◽  
Recessive Ataxia ◽  
Internet Resources ◽  
Genetic Abnormalities ◽  
Repeat Expansions ◽  
The Common ◽  
Inherited Ataxias

The inherited ataxias are disorders that cause progressive imbalance as a result of pathology in the cerebellum and its various connecting pathways. Autosomal recessive ataxias include Friedreich ataxia, ataxia with isolated vitamin E deficiency, ataxia-telangiectasia, and autosomal recessive ataxia of Charlevoix-Saguenay, among others. A discussion of autosomal dominant ataxias covers spinocerebellar ataxias (SCA) types 1 through 14, dentatorubral pallidoluysian atrophy (DRPLA), and episodic ataxia (EA) syndromes. Clinical features, laboratory studies, differential diagnosis, and management of inherited ataxias are discussed. Tables describe both autosomal recessive ataxias and autosomal dominant ataxias (with known gene loci), childhood– or young adult–onset ataxias with ill-defined genetic abnormalities, phenotypic features that may indicate a specific genotype in the common autosomal dominant ataxias, and normal and expanded ranges of various repetitive nucleotide sequences in inherited ataxias. Figures include a diagrammatic representation of the type of repeat expansions associated with ataxias, aggregates of ataxin 3, a schematic of some of the proposed pathogenic mechanisms in the polyglutamine ataxias, and dystonia in a patient with SCA3. A sidebar offers selected Internet resources for information on ataxias. This chapter contains 64 references.

Interhemispheric Connectivity in Idiopathic Cervical Dystonia and Spinocerebellar Ataxias: A Transcranial Magnetic Stimulation Study

2020 ◽  
pp. 155005942095748 ◽  
Author(s):  
Tommaso Bocci ◽  
Davide Baloscio ◽  
Roberta Ferrucci ◽  
Lucia Briscese ◽  
Alberto Priori ◽  
...  
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Cervical Dystonia ◽  
Magnetic Stimulation ◽  
Silent Period ◽  
Cortical Inhibition ◽  
Common Disease ◽  
Conduction Time ◽  
Mutational Load ◽  
Spinocerebellar Ataxias ◽  
Interhemispheric Communication

Background and Rationale Hyperkinetic movement disorders represent a heterogeneous group of diseases, different from a genetic and clinical perspective. In the past, neurophysiological approaches provided different, sometimes contradictory findings, pointing to an impaired cortical inhibition as a common electrophysiological marker. Our aim was to evaluate changes in interhemispheric communication in patients with idiopathic cervical dystonia (ICD) and spinocerebellar ataxias (SCAs). Materials and Methods Eleven patients with ICD, 7 with genetically confirmed SCA2 or SCA3, and 10 healthy volunteers were enrolled. The onset latency and duration of the ipsilateral silent period (iSPOL and iSPD, respectively), as well as the so-called transcallosal conduction time (TCT), were then recorded from the abductor pollicis brevis of the right side using an 8-shaped focal coil with wing diameters of 70 mm; all these parameters were evaluated and compared among groups. In SCAs, changes in neurophysiological measures were also correlated to the mutational load. Results iSPD was significantly shorter in patients with SCA2 and SCA3, when compared both to control and ICD ( P < .0001); iSPOL and TCT were prolonged in SCAs patients ( P < .001). Changes in iSPD, iSPOL, and TCT in SCAs are significantly correlated with the mutational load ( P = .01, P = .02, and P = .002, respectively). Discussion This is the first study to assess changes in interhemispheric communication in patients with SCAs and ICD, using a transcranial magnetic stimulation protocol. Together with previous data in Huntington’s disease, we suggest that these changes may underlie, at least in part, a common disease mechanism of polyglutamine disorders.

scholarly journals Tumour-specific Causal Inference Discovers Distinct Disease Mechanisms Underlying Cancer Subtypes

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Yifan Xue ◽  
Gregory Cooper ◽  
Chunhui Cai ◽  
Songjian Lu ◽  
Baoli Hu ◽  
...  
Keyword(s):  
Causal Inference ◽  
The Cancer Genome Atlas ◽  
Common Disease ◽  
Precision Oncology ◽  
Breast Cancers ◽  
Cancer Subtypes ◽  
Disease Mechanisms ◽  
Distinct Disease ◽  
Somatic Genome ◽  
Survival Patterns

Abstract Cancer is a disease mainly caused by somatic genome alterations (SGAs) that perturb cellular signalling systems. Furthermore, the combination of pathway aberrations in a tumour defines its disease mechanism, and distinct disease mechanisms underlie the inter-tumour heterogeneity in terms of disease progression and responses to therapies. Discovering common disease mechanisms shared by tumours would provide guidance for precision oncology but remains a challenge. Here, we present a novel computational framework for revealing distinct combinations of aberrant signalling pathways in tumours. Specifically, we applied the tumour-specific causal inference algorithm (TCI) to identify causal relationships between SGAs and differentially expressed genes (DEGs) within tumours from the Cancer Genome Atlas (TCGA) study. Based on these causal inferences, we adopted a network-based method to identify modules of DEGs, such that the member DEGs within a module tend to be co-regulated by a common pathway. Using the expression status of genes in a module as a surrogate measure of the activation status of the corresponding pathways, we divided breast cancers (BRCAs) into five subgroups and glioblastoma multiformes (GBMs) into six subgroups with distinct combinations of pathway aberrations. The patient groups exhibited significantly different survival patterns, indicating that our approach can identify clinically relevant disease subtypes.

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