RYR1 and autosomal recessive centronuclear myopathy: RYR1-related autosomal recessive centronuclear myopathy (RYR1-related ARCNM, OMIM#255320) is caused by mutations in the RYR1 gene encoding the ryanodine receptor, which is the main sarcoplasmic reticulum (SR) calcium release channel in skeletal muscle [8] (Table 1).