Congenital myasthenic syndrome due to DOK7 mutation in a cohort of patients with 'unexplained' limb-girdle muscular weakness

J Clin Neurosci. 2020 May;75:195-198. doi: 10.1016/j.jocn.2020.01.080. Epub 2020 Mar 29.


Congenital myasthenic syndromes (CMS) associated with pathogenic variants in the DOK7 gene (DOK7-CMS) have phenotypic overlap with other neuromuscular disorders associated with limb-girdle muscular weakness (LGMW). Genetic analysis of the most common mutation (c.1124_1127dupTGCC) in DOK7 was performed in 34 patients with "unexplained" LGMW associated with non-specific changes in muscle biopsy. Of the 34 patients, one patient showed the DOK7 c.1124_1127dupTGCC variant in homozygousity. Our study estimates the minimum prevalence of undiagnosed DOK7-CMS to be 2.9% in southern Brazilian patients from our centre. Our data confirm that clinicians should look for DOK7-CMS patients when the clinical manifestation is an 'unexplained' LGMW, mainly if associated with non-specific changes in muscle biopsy.

Keywords: Congenital myasthenic syndrome; DOK7 gene; Limb-girdle muscular weakness; Muscle biopsy.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Brazil / epidemiology
  • Cohort Studies
  • Female
  • Genetic Testing / methods
  • Humans
  • Male
  • Middle Aged
  • Muscle Proteins / genetics*
  • Muscle Weakness / diagnosis
  • Muscle Weakness / epidemiology
  • Muscle Weakness / genetics
  • Muscular Dystrophies, Limb-Girdle / diagnosis*
  • Muscular Dystrophies, Limb-Girdle / epidemiology
  • Muscular Dystrophies, Limb-Girdle / genetics*
  • Mutation / genetics*
  • Myasthenic Syndromes, Congenital / diagnosis*
  • Myasthenic Syndromes, Congenital / epidemiology
  • Myasthenic Syndromes, Congenital / genetics*
  • Retrospective Studies
  • Young Adult


  • DOK7 protein, human
  • Muscle Proteins