X-linked centronuclear myopathy or myotubular myopathy (XLCNM, XLMTM, OMIM#310400) is caused by recessive mutations in the MTM1 gene encoding the 3′-phosphoinositide phosphatase myotubularin [3] (Table 1). This evidence concerns the gene MTMR2 and X-linked myotubular myopathy.