CTTN and myasthenia gravis: Aside from Abs against these extracellularly exposed soluble or transmembrane autoantigens, some MG patients harbour Abs against the intracellular proteins titin (present in 20–30% of AChR+ MG) [18], ryanodine receptor (RyR; present in 70% of TAMG) [19] and cortactin (present in 5–10% of AChR+ MG) [20].