TTN and neuromuscular disease: TTN variants are currently known to cause several neuromuscular diseases, including TMD (distal myopathy), LGMD2 J (an early onset, proximal myopathy; Hackman et al., 2008), HMERF (muscle weakness progressing from distal lower limbs to generalized weakness; Pfeffer et al., 2012), and centronuclear myopathy (recessive congenital myopathy; Ceyhan‐Birsoy et al., 2013) among others.