Clinical features of RYR1 -related MmD are more variable: Extraocular muscle involvement (ophthalmoparesis) is common, often associated with axial and proximal weakness, and
[nature.com]
Muscle biopsy performed in the older brother showed increase in fibrosis, variation in fiber size, type I fibre predominance, and the presence of central and eccentric cores
[cags.org.ae]
In other patients, there is marked weakness of the axial muscles and/or the face; a minority have prominent distal involvement.
[clinicalgate.com]