Myasthenia gravis is an autoimmune disorder and antibodies against which of the following can cause the disease?

MG is an autoimmune disorder most commonly caused by anti- AChR antibodies. The anti-AChR antibodies reduce the number of available AChRs. An immune response to muscle-specific kinase (MuSK), a protein involved in AChR clustering at the NMJ, can also result in MG, with reduction of AChRs demonstrated experimentally. Anti-MuSK antibody occurs in about 10% of patients (about 40% of AChR antibody negative patients), while 1-3% have antibodies to another protein at the NMJ--low-density lipoprotein receptor-related protein 4 (LRP4)--that is also impoant for clustering of AChRs. The pathogenic antibodies are IgG and are T cell dependent. Ref harrison 20th edition page 3232