Different types of intra-saccadic slowing in congenital (RAPSN-mutation) and acquired myasthenic syndromes

Saccadic slowing and saccadic fatigue is a common clinical finding in myasthenia gravis [1]. However, previous studies on eye movements in myasthenia gravis did not dissociate congenital (CMS) from acquired forms with acetylcholine‐receptor (ACHR) auto‐antibodies [1]. Therefore, saccades of one patient with CMS caused by two compound heterozygote mutations (N88K and 1177 del AA) in the RAPSN gene (2) (one mutation from each parent) were compared with three patients with acquired myasthenia gravis and two healthy controls.