A European epidemiologic study showed a dominance of GPA over MPA [4], while our prospective study [5] and two retrospective studies from China [6] and Japan [3] that applied the EMEA algorithm found perinuclear/myeloperoxidase (MPO)-ANCA-positive MPA to be the most common form of AAV in Asia. The gene discussed is GYPA; the disease is microscopic polyangiitis.