HCN ion channels and accessory proteins in epilepsy: genetic analysis of a large cohort of patients and review of the literature

Jacopo C DiFrancesco, Barbara Castellotti, Raffaella Milanesi, Francesca Ragona, Elena Freri, Laura Canafoglia, Silvana Franceschetti, Carlo Ferrarese, Stefania Magri, Franco Taroni, Cinzia Costa, Angelo Labate, Antonio Gambardella, Roberta Solazzi, Anna Binda, Ilaria Rivolta, Giancarlo Di Gennaro, Sara Casciato, Ludovico D'Incerti, Andrea BarbutiDario DiFrancesco, Tiziana Granata, Cinzia Gellera

Research output: Contribution to journalReview article

Abstract

The Hyperpolarization-activated Cyclic Nucleotide-gated (HCN) channels are highly expressed in the Central Nervous Systems, where they are responsible for the Ih current. Together with specific accessory proteins, these channels finely regulate neuronal excitability and discharge activity. In the last few years, a substantial body of evidence has been gathered showing that modifications of Ih can play an important role in the pathogenesis of epilepsy. However, the extent to which HCN dysfunction is spread among the epileptic population is still unknown. The aim of this work is to evaluate the impact of genetic mutations potentially affecting the HCN channels' activity, using a NGS approach. We screened a large cohort of patients with epilepsy of unknown etiology for mutations in HCN1, HCN2 and HCN4 and in genes coding for accessory proteins (MiRP1, Filamin A, Caveolin-3, TRIP8b, Tamalin, S-SCAM and Mint2). We confirmed the presence of specific mutations of HCN genes affecting channel function and predisposing to the development of the disease. We also found several previously unreported additional genetic variants, whose contribution to the phenotype remains to be clarified. According to these results and data from literature, alteration of HCN1 channel function seems to play a major role in epilepsy, but also dysfunctional HCN2 and HCN4 channels can predispose to the development of the disease. Our findings suggest that inclusion of the genetic screening of HCN channels in diagnostic procedures of epileptic patients should be recommended. This would help pave the way for a better understanding of the role played by Ih dysfunction in the pathogenesis of epilepsy.

Original languageEnglish
Pages (from-to)49-58
Number of pages10
JournalEpilepsy Research
Volume153
DOIs
Publication statusPublished - Jul 2019

Keywords

  • Cadherins/genetics
  • Carrier Proteins/genetics
  • Caveolin 3/genetics
  • Cohort Studies
  • Electroencephalography
  • Epilepsy/genetics
  • Family Health
  • Female
  • Filamins/genetics
  • Genetic Testing
  • Humans
  • Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels/genetics
  • Male
  • Membrane Proteins/genetics
  • Mutation/genetics
  • Nerve Tissue Proteins/genetics
  • Potassium Channels, Voltage-Gated/genetics
  • Receptors, Cytoplasmic and Nuclear/genetics

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  • Cite this

    DiFrancesco, J. C., Castellotti, B., Milanesi, R., Ragona, F., Freri, E., Canafoglia, L., Franceschetti, S., Ferrarese, C., Magri, S., Taroni, F., Costa, C., Labate, A., Gambardella, A., Solazzi, R., Binda, A., Rivolta, I., Di Gennaro, G., Casciato, S., D'Incerti, L., ... Gellera, C. (2019). HCN ion channels and accessory proteins in epilepsy: genetic analysis of a large cohort of patients and review of the literature. Epilepsy Research, 153, 49-58. https://doi.org/10.1016/j.eplepsyres.2019.04.004