Journal Article

130329 Static on the line: the interrupted conversation between nerve and muscle in congenital myasthenic syndromes

Liu, Tracie, Anderson, Ellie, Munshi Vineeta

2025

Overview

The congenital myasthenic syndromes are a body of inherited neuromuscular disorders caused by defects in the neuromuscular junction, posing a challenging differential with varied genotypes and phenotypes. With an incidence of 22.2 cases per million children, this condition can be easily overlooked and investigated as conditions with similar presentations, such as congenital fibrosis of extraocular muscles. Early diagnosis however, is crucial for optimal treatment given the potential systemic complications, such as respiratory distress, and potential long-term visual consequences such as amblyopia. This case series will discuss four patients with CMS and their presentation, diagnostic process, disease progression, and response to pyridostigmine.Four Slovakian patients presenting between the ages eleven months and seven years were referred into the local Ophthalmology services with poor vision and ptosis as primary complaints. On examination, all had ophthalmoplegia worse on upgaze initially which progressively involved other directions of gaze. All patients were referred to neurology for joint management and further investigations including EMG testing, anti-AChR and anti-MuSK antibodies, and genetic testing. There was an average time of presentation to genetic diagnosis of 26.5 months. On gene sequencing, all were homozygous for CHRNE, the gene accounting for over 50% of CMS cases. Of the four patients, three had partial or little improvement only in symptoms on pyridostigmine, with one not tolerating the side effects.CMS still presents diagnostic uncertainty to clinicians. An awareness of these conditions, however rare, is vital as an Ophthalmologist as they can be a first presentation to medical services via Ophthalmology.

• Publisher: BMJ Publishing Group LTD
• Subject: Ophthalmology