RYR1 and congenital myopathy with cores: Mutations in RYR1 are the most common genetic cause of nondystrophic neuromuscular disorders,1,2 associated with a wide spectrum of clinicopathologic features, ranging from various early-onset congenital myopathies—central core disease,3 multiminicore disease (MmD),4 centronuclear myopathy,5 and congenital fiber type disproportion6—to the malignant hyperthermia (MH) susceptibility trait.