Of 93 MG patients, 7 were positive for agrin autoantibodies: 5 were AChR+, but MuSK- and LRP4- patients and 2 were from patients who were ‘triple seronegative’ (no AChR, MuSK or LRP4 antibodies) (Fig. 2). This evidence concerns the gene LRP4 and myasthenia gravis.