PRTN3 and infective endocarditis: <h4>Background</h4>Proteinase 3-antineutrophil cytoplasmic antibody has been reported to be positive in 5-10% of cases of renal injury complicated by infective endocarditis; however, histological findings have rarely been reported for these cases.<h4>Case presentation</h4>A 71-year-old Japanese man with a history of aortic valve replacement developed rapidly progressive renal dysfunction with gross hematuria and proteinuria.