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Early onset ataxia with comorbid myoclonus and epilepsy : A disease spectrum with shared molecular pathways and cortico-thalamo-cerebellar network involvement

van Noort, Suus A M ; van der Veen, Sterre ; de Koning, Tom J LU ; de Koning-Tijssen, Marina A J ; Verbeek, Dineke S and Sival, Deborah A (2023) In European Journal of Paediatric Neurology 45. p.47-54
Abstract

OBJECTIVES: Early onset ataxia (EOA) concerns a heterogeneous disease group, often presenting with other comorbid phenotypes such as myoclonus and epilepsy. Due to genetic and phenotypic heterogeneity, it can be difficult to identify the underlying gene defect from the clinical symptoms. The pathological mechanisms underlying comorbid EOA phenotypes remain largely unknown. The aim of this study is to investigate the key pathological mechanisms in EOA with myoclonus and/or epilepsy.

METHODS: For 154 EOA-genes we investigated (1) the associated phenotype (2) reported anatomical neuroimaging abnormalities, and (3) functionally enriched biological pathways through in silico analysis. We assessed the validity of our in silico results... (More)

OBJECTIVES: Early onset ataxia (EOA) concerns a heterogeneous disease group, often presenting with other comorbid phenotypes such as myoclonus and epilepsy. Due to genetic and phenotypic heterogeneity, it can be difficult to identify the underlying gene defect from the clinical symptoms. The pathological mechanisms underlying comorbid EOA phenotypes remain largely unknown. The aim of this study is to investigate the key pathological mechanisms in EOA with myoclonus and/or epilepsy.

METHODS: For 154 EOA-genes we investigated (1) the associated phenotype (2) reported anatomical neuroimaging abnormalities, and (3) functionally enriched biological pathways through in silico analysis. We assessed the validity of our in silico results by outcome comparison to a clinical EOA-cohort (80 patients, 31 genes).

RESULTS: EOA associated gene mutations cause a spectrum of disorders, including myoclonic and epileptic phenotypes. Cerebellar imaging abnormalities were observed in 73-86% (cohort and in silico respectively) of EOA-genes independently of phenotypic comorbidity. EOA phenotypes with comorbid myoclonus and myoclonus/epilepsy were specifically associated with abnormalities in the cerebello-thalamo-cortical network. EOA, myoclonus and epilepsy genes shared enriched pathways involved in neurotransmission and neurodevelopment both in the in silico and clinical genes. EOA gene subgroups with myoclonus and epilepsy showed specific enrichment for lysosomal and lipid processes.

CONCLUSIONS: The investigated EOA phenotypes revealed predominantly cerebellar abnormalities, with thalamo-cortical abnormalities in the mixed phenotypes, suggesting anatomical network involvement in EOA pathogenesis. The studied phenotypes exhibit a shared biomolecular pathogenesis, with some specific phenotype-dependent pathways. Mutations in EOA, epilepsy and myoclonus associated genes can all cause heterogeneous ataxia phenotypes, which supports exome sequencing with a movement disorder panel over conventional single gene panel testing in the clinical setting.

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author
; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Early onset ataxia, myoclonus, Epilepsy, Child, Neurodevelopment, Netwoek, Clinical genetics, Phenotype, Bioinformatics
in
European Journal of Paediatric Neurology
volume
45
pages
28 pages
publisher
Elsevier
external identifiers
  • scopus:85161593115
  • pmid:37301083
ISSN
1090-3798
DOI
10.1016/j.ejpn.2023.05.009
language
English
LU publication?
yes
id
14e2b72b-66b5-42d6-8ea8-a67dd6ff0ce2
date added to LUP
2023-06-26 12:02:35
date last changed
2024-04-19 23:06:34
@article{14e2b72b-66b5-42d6-8ea8-a67dd6ff0ce2,
  abstract     = {{<p>OBJECTIVES: Early onset ataxia (EOA) concerns a heterogeneous disease group, often presenting with other comorbid phenotypes such as myoclonus and epilepsy. Due to genetic and phenotypic heterogeneity, it can be difficult to identify the underlying gene defect from the clinical symptoms. The pathological mechanisms underlying comorbid EOA phenotypes remain largely unknown. The aim of this study is to investigate the key pathological mechanisms in EOA with myoclonus and/or epilepsy.</p><p>METHODS: For 154 EOA-genes we investigated (1) the associated phenotype (2) reported anatomical neuroimaging abnormalities, and (3) functionally enriched biological pathways through in silico analysis. We assessed the validity of our in silico results by outcome comparison to a clinical EOA-cohort (80 patients, 31 genes).</p><p>RESULTS: EOA associated gene mutations cause a spectrum of disorders, including myoclonic and epileptic phenotypes. Cerebellar imaging abnormalities were observed in 73-86% (cohort and in silico respectively) of EOA-genes independently of phenotypic comorbidity. EOA phenotypes with comorbid myoclonus and myoclonus/epilepsy were specifically associated with abnormalities in the cerebello-thalamo-cortical network. EOA, myoclonus and epilepsy genes shared enriched pathways involved in neurotransmission and neurodevelopment both in the in silico and clinical genes. EOA gene subgroups with myoclonus and epilepsy showed specific enrichment for lysosomal and lipid processes.</p><p>CONCLUSIONS: The investigated EOA phenotypes revealed predominantly cerebellar abnormalities, with thalamo-cortical abnormalities in the mixed phenotypes, suggesting anatomical network involvement in EOA pathogenesis. The studied phenotypes exhibit a shared biomolecular pathogenesis, with some specific phenotype-dependent pathways. Mutations in EOA, epilepsy and myoclonus associated genes can all cause heterogeneous ataxia phenotypes, which supports exome sequencing with a movement disorder panel over conventional single gene panel testing in the clinical setting.</p>}},
  author       = {{van Noort, Suus A M and van der Veen, Sterre and de Koning, Tom J and de Koning-Tijssen, Marina A J and Verbeek, Dineke S and Sival, Deborah A}},
  issn         = {{1090-3798}},
  keywords     = {{Early onset ataxia; myoclonus; Epilepsy; Child; Neurodevelopment; Netwoek; Clinical genetics; Phenotype; Bioinformatics}},
  language     = {{eng}},
  month        = {{05}},
  pages        = {{47--54}},
  publisher    = {{Elsevier}},
  series       = {{European Journal of Paediatric Neurology}},
  title        = {{Early onset ataxia with comorbid myoclonus and epilepsy : A disease spectrum with shared molecular pathways and cortico-thalamo-cerebellar network involvement}},
  url          = {{http://dx.doi.org/10.1016/j.ejpn.2023.05.009}},
  doi          = {{10.1016/j.ejpn.2023.05.009}},
  volume       = {{45}},
  year         = {{2023}},
}