PROTEINURIA AND OTHER RENAL FUNCTIONS IN WILSONS-DISEASE

Renal lesions have repeatedly been described in Wilson's disease (WD). We investigated the excretion of total protein, albumin, low (LMW) an d high molecular weight (HMW) proteins, N-acetyl-beta-D-glucosaminidas e (NAG), and calcium, as well as creatinine clearance, in 24-h urine s amples of 41 patients with WD aged 6-37 (mean 17) years who had been t reated for a period of 0-15 (mean 4.5) years with D-penicillamine (900 mg/day). The amount of all protein excreted was significantly increas ed compared with controls, 39% of patients presenting with total prote inuria more than two standard deviations from the mean of controls. Th e changes in protein excretion depended on the duration of treatment. LMW proteinuria was elevated almost exclusively in the first 2 years a fter the start of treatment, indicating early tubular damage. This is supported by an initially high excretion of beta(2)-microglobulin, NAG , and calcium. Increased excretion of HMW proteins, including albumin, persisted over longer periods, which suggests glomerular injury in so me patients, possibly related to the use of D-penicillamine, Creatinin e clearance remained roughly within normal limits. We propose that ren al function should regularly be checked in patients with WD.