In terms of the criteria for MPA, the patient achieved a total score of 5 owing to the items of MPO-ANCA (or P-ANCA) positivity (+6), MPA-related lung lesions (+3), and serum eosinophil count ≥ 1000/μL (−4) and could be reclassified as having OvSD/pSS/MPA. The gene discussed is MPO; the disease is microscopic polyangiitis.