Conversely, a low ADAMTS13 activity/ADAMTS13 Ag ratio was associated with mild and severe renal dysfunction, and with micro and macroalbuminuria, suggesting that the rise in ADAMTS13 Ag levels is not accompanied by a proportional increase in ADAMTS13 activity and VWF cleavage in these patients. The gene discussed is VWF; the disease is Abnormal renal physiology.