Supplementary file 1_Case Report: A case of focal segmental glomerulosclerosis in Wilson’s disease induced by penicillamine.docx

Wilson’s disease (WD) is a hereditary disorder that impairs copper metabolism. Both WD and its treatment with penicillamine are associated with renal impairment. We report a case of penicillamine-induced podocytopathy with pathological findings of early-stage focal segmental glomerulosclerosis (FSGS), which demonstrated rapid reversibility upon drug withdrawal alone. A 36-year-old female of East Asian origin with a 12-year history of WD presented with nephrotic syndrome after 21 months of penicillamine therapy. Her 24-h proteinuria was 6.58 g. Her renal biopsy revealed a podocytopathy with early-stage FSGS lesions. Following discontinuation of penicillamine, the proteinuria decreased to 0.04 g/24 h and the nephrotic syndrome reached complete remission in 16 days without corticosteroid therapy. Remission persisted at the 1-year follow-up. This case illustrates that penicillamine can be a cause of reversible nephrotic syndrome secondary to podocytopathy with FSGS lesions and emphasizes the need for early biopsy in unusual proteinuria, with discontinuation of drugs as the main intervention. The clinician should have a high index of suspicion for drug toxicity in patients with WD and nephrotic syndrome, especially if the kidney injury is time-related to penicillamine therapy.