TTN and myasthenia gravis: On the other hand, RYR (ryanodine receptor, a Ca2+ release channel of the sarcoplasmic reticulum of striated muscle) and Titin (giant filamentous muscle protein) antibodies belong to non‐AChR muscle autoantibodies and present high specificity for thymomatous MG and late onset MG (age ≥ 50 years).22, 23, 24, 25