Study of a large British series of patients with congenital myotonia confirms the value of functional genetic studies

Patients with non-dystrophic myotonia represent a very small contingent of individuals compared to all patients with myotonia. 

British clinicians have studied 223 families in which a diagnosis of congenital myotonia linked to the chlorine channel has been identified. It appears that : 

• the two different modes of transmission, autosomal dominantEn génétique, c’est la caractéristique d’un individu qui n’a besoin que d’un seul exemplaire d’un certain gène (allèle) pour s’exprimer. Cet exemplaire unique peut venir du père ou de la mère. or autosomal recessive, are sometimes difficult to determine; 
• functional studies of pathogenic variants of the CLCN1 gene, such as those carried out in 95 patients in the series, are interesting to guide the interpretation of clinical and electrophysiological data, as well as the mode of transmission.

Translating genetic and functional data into clinical practice: a series of 223 families with myotonia. Suetterlin K, Matthews E, Sud R, et al Brain. 2021 (Sept)