Nephrotic range proteinuria as a presenting feature of classical nephropathic cystinosis.

Patients with renal tubular acidosis (RTA) usually have tubular or low molecular weight proteinuria. The authors present a rare case of a 6-y-old girl with Fanconi syndrome secondary to cystinosis, who at presentation had nephrotic range proteinuria along with rickets and failure to thrive. Although hypoalbuminemia and massive proteinuria are characteristics of nephrotic syndrome, there are other conditions which can present with massive proteinuria.