LRP4 and myasthenia gravis: Most patients with MG (80–88%) have pathogenic IgG autoantibodies against the acetylcholine receptor (AChR), while a small minority are autoantibody-positive for muscle-specific kinase (MuSK, < 10%) or low-density lipoprotein receptor-related protein 4 (LRP4, 1%), or are seronegative (10–15%) [6–10].