MUSK and myasthenia gravis: AChR antibodies (80%), MuSK antibodies (1–10%), LRP4 antibodies (1–5%), agrin antibodies (minority), titin antibodies (20–30% of AChR-MG), potassium voltage-gated channel subfamily A member 4 antibodies (10–20%), ryanodine receptor antibodies (70% of MG with thymoma and 14% of late-onset AChR-MG)