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. Here, CCDC78 is linked to congenital myopathy with cores.