As shown in Figure 4, the frequencies of each antibody in the 1948 cases of MG patients were as follows: Agrin-Ab, 0.92%; AChR-Ab, 71.66%; MuSK-Ab, 2.56%; LRP4-Ab, 0.78%; other (AChR-Ab, MuSK-Ab, LRP4-Ab, and Agrin-Ab not detected), 24.84%. Here, MUSK is linked to myasthenia gravis.