Balkan tubulointerstitial nephritis /to̅o̅′byəlō·in′tər- stish″-əl/ , a chronic kidney disorder marked by renal insufficiency, proteinuria, tubulointerstitial nephritis, and anemia. The onset is gradual, but end-stage disease occurs within 5 years after the first signs. About one third of the patients also suffer from urinary tract cancers. The disease is endemic in the Balkans but is not hereditary.