A rare cause of nephrotic syndrome in autosomal-dominant polycystic kidney disease.

We report the case of a 49-year-old lady who presented with hypertension, breathlessness and malaise. She was thrombocytopenic, with polycystic kidneys on imaging, and was found to have nephrotic syndrome. Serological results were consistent with systemic lupus erythematosus (SLE) and a renal biopsy confirmed WHO class V lupus nephritis. This is the first reported case of nephrotic syndrome due to lupus nephritis in a patient with autosomal dominant polycystic kidney disease (ADPKD) and underlines the importance of renal biopsy in patients with ADPKD and nephrotic range proteinuria.