A 15-year-old girl was seen by her family physician because of increasing lethargy. She had a recent history of the "flu". Biochemistry tests show that she has renal impairement. serum sodium 140 mmol/L (137 - 144) serum potassium 4.2 mmol/L (3.5 - 4.9) serum urea 28 mol/L (2.5 - 7.5) serum creatinine 280 µmol/L (60 - 110) Her condition does not improve after several weeks on corticosteroid therapy, so a renal biopsy is performed. The biopsy demonstrates the presence of segmental sclerosis of 3 of 10 glomeruli identified in the biopsy specimen. Immunofluorescence studies and electron microscopy do not reveal evidence for immune deposits. What is the most appropriate advice to give regarding her condition? 1) She has an underlying malignancy 2) She may require a renal transplant in 10 years 3) She will improve if she loses weight 4) She will likely develop a restrictive lung disease 5) She will probably improve with additional corticosteroid therapy