Kidney injury molecule-1 expression identifies proximal tubular injury in urate nephropathy.

Urate nephropathy in children is uncommon, occurring mostly in those who have undergone chemotherapy or radiotherapy. The characteristic obstruction of distal nephron tubules by uric acid precipitates is considered key to the subsequent parenchymal injury. Whether proximal tubular injury plays a role in urate nephropathy remains unclear. We report one case of acute urate nephropathy and one case of chronic urate nephropathy in two pediatric patients. In their renal biopsies, we demonstrate upregulation of kidney injury molecule-1 (KIM-1), a specific injury marker, in proximal tubular cells. This finding implicates a role for proximal tubular injury in urate nephropathy.