A recurrent RYR1 mutation associated with early-onset hypotonia and benign disease course

Valérie Biancalana*, John Rendu*, Annabelle Chaussenot, Helen Mecili, Eric Bieth, Mélanie Fradin, Sandra Mercier, Maud Michaud, Marie Christine Nougues, Laurent Pasquier, Sabrina Sacconi, Norma B. Romero, Pascale Marcorelles, François Jérôme Authier, Antoinette Gelot Bernabe, Emmanuelle Uro-Coste, Claude Cances, Bertrand Isidor, Armelle Magot, Marie Christine Minot-MyhieYann Péréon, Julie Perrier-Boeswillwald, Gilles Bretaudeau, Nicolas Dondaine, Alison Bouzenard, Mégane Pizzimenti, Bruno Eymard, Ana Ferreiro, Jocelyn Laporte, Julien Fauré, Johann Böhm

*Corresponding author for this work

Research output: Contribution to journalArticleResearchpeer-review

1 Citation (Scopus)


The ryanodine receptor RyR1 is the main sarcoplasmic reticulum Ca2+ channel in skeletal muscle and acts as a connecting link between electrical stimulation and Ca2+-dependent muscle contraction. Abnormal RyR1 activity compromises normal muscle function and results in various human disorders including malignant hyperthermia, central core disease, and centronuclear myopathy. However, RYR1 is one of the largest genes of the human genome and accumulates numerous missense variants of uncertain significance (VUS), precluding an efficient molecular diagnosis for many patients and families. Here we describe a recurrent RYR1 mutation previously classified as VUS, and we provide clinical, histological, and genetic data supporting its pathogenicity. The heterozygous c.12083C>T (p.Ser4028Leu) mutation was found in thirteen patients from nine unrelated congenital myopathy families with consistent clinical presentation, and either segregated with the disease in the dominant families or occurred de novo. The affected individuals essentially manifested neonatal or infancy-onset hypotonia, delayed motor milestones, and a benign disease course differing from classical RYR1-related muscle disorders. Muscle biopsies showed unspecific histological and ultrastructural findings, while RYR1-typical cores and internal nuclei were seen only in single patients. In conclusion, our data evidence the causality of the RYR1 c.12083C>T (p.Ser4028Leu) mutation in the development of an atypical congenital myopathy with gradually improving motor function over the first decades of life, and may direct molecular diagnosis for patients with comparable clinical presentation and unspecific histopathological features on the muscle biopsy.

Original languageEnglish
Article number155
JournalActa neuropathologica communications
Issue number1
Publication statusPublished - Dec 2021
Externally publishedYes


  • Calcium
  • Congenital myopathy
  • Excitation–contraction coupling
  • Muscle weakness
  • Neuromuscular disorder
  • Triad


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