Although PR3-ANCA is known as a disease marker for GPA and myeloperoxidase (MPO)-ANCA is known as a marker for microscopic polyangiitis (MPA) or eosinophilic granulomatosis with polyangiitis (EGPA), the transfer of antibodies has been observed within AAV, and MPO-ANCA positive GPA has been reported. This evidence concerns the gene MPO and microscopic polyangiitis.