Case report: Novel SCN4A variant associated with a severe congenital myasthenic syndrome/myopathy phenotype.

ABSTRACT: We present a now 18-year-old female patient with a severe congenital myopathy phenotype, originally diagnosed as mitochondrial myopathy, however later revealed to constitute a SCN4A-related myopathy based on genetic testing. After birth, floppiness, bradycardia and respiratory insufficiency ensued, and moderately reduced mitochondrial complex I activity was found in muscle tissue (tested at 3 weeks and 3 years of age, respectively). She was treated with riboflavin, carnitine, creatine and a ketogenic diet. At the age of 13 years, whole exome sequencing challenged the initial diagnosis by identifying two (compound heterozygous) SCN4A variants affecting the highly conserved voltage sensor and pore regions of the voltage-gated sodium channel Na_V1.4: a known pathogenic

SUBMITTER: Berghold VM 

PROVIDER: S-EPMC9462513 | biostudies-literature | 2022

REPOSITORIES: biostudies-literature