RYR1 and ptosis: In particular, patients with recessive RYR1 mutations often display involvement of extraocular muscles leading to ophthalmoplegia and or ptosis as well as involvement of respiratory muscles, often requiring assisted ventilation (Jungbluth et al., 2018; Treves et al., 2008; Lawal et al., 2020; Wilmshurst et al., 2010; Jungbluth et al., 2005).