TTN and tibial muscular dystrophy: Several studies have reported M-line TTN mutations in various skeletal muscle diseases including centronuclear myopathy (CM, MIM #160150) [29], tibial muscular dystrophy (TMD, MIM #600334) [30, 31], early-onset myopathy (MIM #611705) [6], distal myopathy and limb girdle muscular dystrophy 2J (LGMD2J, MIM #608807) [32], with or without cardiac muscle involvement.