MITF and myositis disease: -Muscle strength examination;-Skin evaluation;-Evaluation of vision and ocular muscles;-Blood panel including CK, AST, ALT, LDH, aldolase, troponin, NT-proBNP, ESR, CRP, ANA (with myositis panel, e.g., Jo1,Mi-2,SRP, etc.), and AChR antibodies;-Electrocardiogram or Echocardiogram;-Consider electromyography, MRI, and muscle biopsy.