Pathogenic gene variants in a few CMS genes may rarely cause diagnostic confusion with “treatment resistant ocular ± generalized myasthenia”; pathogenic variants in CHRNE1 have been reported to present after infancy with mild ptosis or ophthalmoplegia and respond to cholinesterase inhibitors; DOK7 pathogenic variants may present with limb-girdle weakness and ptosis; occasional pathogenic variants in RAPSN may cause fluctuating ptosis with/without generalized fatigability (36, 47). This evidence concerns the gene RAPSN and ophthalmoplegia.