Myositis specific autoantibodies including Jo-1, ARS, MDA5, TiF1γ, Mi-2, Ku, PL-7, PL-10, OJ, EJ, HMGCR, SRP and myasthenic gravis related antibodies including anti AChR and MuSK antibody were negative. The gene discussed is MUSK; the disease is myositis disease.