MG is divided into four subgroups according to the different antibodies: acetylcholine receptor (AChR) MG, muscle-specific kinase (MuSK) MG, low-density lipoprotein receptor-related protein4 (LRP-4) MG, and triple-seronegative (triple-SN) MG (1, 2). Here, LRP4 is linked to myasthenia gravis.