RYR1 and congenital myopathy with cores: The neuromuscular disorder due to dominant mutations in the CCDC78 gene encoding Coiled-Coil Domain-Containing 78 (Majczenko et al., 2012) is another example of a congenital myopathy difficult to classify on histopathological grounds due to the common occurrence of internalized nuclei and cores, containing sarcoplasmic aggregated CCDC78, desmin (DES), actin (ACTA1), and RYR1.