Myotonia congenita: A case series

Abstract

This study examines five patients with confirmed CLCN1 gene mutations associated with myotonia congenita, a rare neuromuscular disorder causing muscle stiffness. Four patients presented milder symptoms with early onset, while one exhibited severe phenotype affecting facial muscles. All patients maintained ambulatory function, though the severe case required a walking stick. Notably, none reported family history, suggesting de novo mutations or incomplete penetrance. The study highlights the phenotypic variability in CLCN1-related myotonia, emphasizing the importance of genetic testing for accurate diagnosis and counseling. The findings contribute to understanding genotype-phenotype relationships in myotonia congenita and stress the need for comprehensive clinical assessments in suspected cases.