Autosomal dominant polycystic kidney disease (ADPKD) is the most common genetic cause of dialysis-requiring end-stage renal disease in adults and is characterized by the slowly progressing replacement of renal tissue by focal macrocysts. Alport syndrome (AS; hereditary nephritis) is a rare, inherited disorder of the basement membrane associated with hematuria, proteinuria, and loss of kidney function as well as sensorineural hearing loss and ocular abnormalities. Here, we report on a family in which both ADPKD and AS are present. In a male patient, both -ADPKD and AS coincided. This patient shows the very rare coexistence of two severe, inherited renal disorders and illustrates the importance of considering additional diagnoses in the setting of positive family history for a common hereditary disorder. .