A familial childhood-onset relapsing nephrotic syndrome

Case 1: An 11-year- old boy (II-2) was referred for evaluation of persistent mild proteinuria without hematuria. His parents and elder brother were negative for urinalysis. The boy had a history of marked 3+ proteinuria at birth. Serological tests for infections and autoantibodies were negative. The nephrotic syndrome (NS) persisted over the next 2 months (Figure 1), but the patient entered a partial remission without any immunosuppressive therapy. He subsequently experienced 2-3 relapses of nephrotic-range per year in association with an upper respiratory infection. Exacerbation of proteinuria usually lasted 1-2 weeks but spontaneously resolved to the level of 1+ to 2+. Biopsies were performed during the patient's nephrosis at 2 months of age and again when he was in partial remission at 5 years of age. Physical examination, renal sonogram, and urogenital studies were normal. Neither hearing loss nor ophthalmologic abnormalities were noted. He is currently receiving treatment with dipyridamole alone. Case 2: Four-year-old sister (II-3) of case 1 visited our clinic for evaluation of persistent proteinuria. She first manifested NS at 10 months of age following an infection. Similar to her affected brother, she spontaneously achieved a partial remission once but thereafter repeated relapses concurrently with respiratory infections. These relapses typically lasted 7 - 10 days and proteinuria remitted to +/- to + without any therapy. She never received any medication or renal biopsy.