Slow Channel Syndrome Revisited: 40 Years Clinical Follow-Up and Genetic Characterization of Two Cases - Sorbonne Université Access content directly
Journal Articles Journal of Neuromuscular Diseases Year : 2022

Slow Channel Syndrome Revisited: 40 Years Clinical Follow-Up and Genetic Characterization of Two Cases

Helena Boon
  • Function : Author
Bram Jacobs
  • Function : Author
van Rheenen Wouter
  • Function : Author
Erik-Jan Kamsteeg
  • Function : Author
Jan Kuks
  • Function : Author
Angela Vincent
  • Function : Author
Nicol Voermans
  • Function : Author

Abstract

Background: The slow channel syndrome is a rare hereditary disorder caused by a dominant gain-of-function variant in one of the subunits of the acetylcholine receptor at the neuromuscular junction. Patients typically experience axial, limb and particularly extensor finger muscle weakness. Objective: Age at diagnosis is variable and although the long-term prognosis is important for newly diagnosed patients, extensive follow-up studies are rare. We aim to provide answers and perspective for this patient group by presenting an elaborate description of the lifetime follow-up of two slow channel syndrome patients. Methods: We describe 40 years follow-up in two, genetically confirmed cases (CHRNA1; c.866G > T p.(Ser289Ile)(legacy Ser269Ile) and CHRNE; c.721C > T p.(Leu241Phe)(legacy Leu221Phe) variants). Results: We find that the disease course has a fluctuating pattern and is only mildly progressive. However, hormonal imbalances, (psychological) stress or excessive hot or cold environments are often aggravating factors. Quinidine and fluoxetine are helpful, but ephedrine and salbutamol may also improve symptoms. Conclusion: Slow channel syndrome is mildly progressive with a fluctuating pattern. The observations reported here provide a lifespan perspective and answers to the most pressing questions about prognosis and treatment options for newly diagnosed patients.

Dates and versions

hal-04577786 , version 1 (16-05-2024)

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Helena Boon, Bram Jacobs, van Rheenen Wouter, Erik-Jan Kamsteeg, Jan Kuks, et al.. Slow Channel Syndrome Revisited: 40 Years Clinical Follow-Up and Genetic Characterization of Two Cases. Journal of Neuromuscular Diseases, 2022, 9 (4), pp.525-532. ⟨10.3233/JND-220798⟩. ⟨hal-04577786⟩
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