Previous phylogenetic analyses [2,3] of myotubularin sequences from human, other vertebrates, and a collection of invertebrates defined six similarity clusters - three composed of catalytically active subunits (in human: ["M1 Group": MTM1 {Myotubular myopathy}, MTMR1 {MTM-related}, MTMR2]; ["R3 Group": MTMR3, MTMR4]; ["R6 Group": MTMR6, MTMR7, MTMR8]) and three composed of catalytically inactive subunits (in human: ["R5 Group": MTMR5, MTMR13]; ["R9 Group": MTMR9]; ["R10 Group": MTMR10, MTMR11, MTMR12]). Here, MTM1 is linked to centronuclear myopathy.