In addition to centrally located nuclei, biopsies in these patients can also reveal the cores characteristically associated with mutations in RYR1. Less commonly, mutations in TTN, which encodes titin, a giant sarcomeric protein [89], in SPEG, which encodes a Z-band protein that shows a strong interaction with MTM1 and also results in dilated cardiomyopathy [90], and in MYF6 and CCDC7 have been reported in a few patients with clinical features reminiscent of centronuclear myopathy [91]. Here, RYR1 is linked to autosomal dominant centronuclear myopathy.