We conclude that RYR1 mutations may give rise to both myopathies and atypical periodic paralysis, and RYR1 mutations may underlie other unresolved cases of periodic paralysis with unusual features.
Cases with a possible diagnosis of PP but additional clinicopathologic findings previously associated with <i>RYR1-</i>related disorders were referred for a tertiary neuromuscular clinical assessment in which they underwent detailed clinical evaluation, including neurophysiologic assessment, muscle biopsy, and muscle MRI.