Patients with a confirmed diagnosis of Alport syndrome who have qualifying GFR will be considered for enrollment. The sequential sampling of subjects' urine and/or blood will allow an assessment of the rate of change of established clinical endpoints, such as GFR and/or the rate of change of other renal biomarkers (proteinuria and β-2 microglobulin) in subjects whose renal function is steadily declining. The identification of surrogate markers that track the decline of renal function and could correlate with time to end-stage renal disease (ESRD) is a key goal of the natural history study.