Diffuse nephrocalcinosis and idiopathic renal hypercalciuria

A 12 year old boy presented with primary nocturnal enuresis. Investigation showed extensive bilateral nephrocalcinosis of no obvious or recognised cause. Persistent severe renal hypercalciuria was confirmed by an intravenous calcium infusion. Idiopathic hypercalciuria is not a common cause of nephrocalcinosis and has not previously been described in a child.