RYR1 and myopathy: While more work is needed to confirm that this persistent ER stress is a defining component of the human RyR1 myopathies and to determine if the potential benefits of 4PBA outweigh any risks in treating this unique subclass of RyR1 myopathy, our work raises the possibility that the clinically approved drug, 4PBA, could be repurposed for use in humans with RyR1 myopathies arising from ER stress.