Focal glomerulosclerosis in patients with unilateral nephrectomy

To investigate whether proteinuria and focal glomerulosclerosis (FSG) might develop in humans as well as in experimental models following a reduction in renal mass, we performed a retrospective study of 24 patients previously nephrectomized for unilateral renal disease. None of the patients presented signs of systemic diseases, Alport syndrome, essential hypertension, reflux nephropathy, and other abnormalities on intravenous pyelography. At the time of the first observation, seven patients had pathological proteinuria (group 1) while 17 presented a normal protein excretion (group 2). All patients in group 1 and only 4 of 17 in group 2 were male. No other significant differences were found between the two groups. The median age at nephrectomy of the proteinuric patients was 22.3 years, and proteinuria developed after a mean period of 12.2 years. A renal biopsy was performed in four patients and showed a constant pattern of FSG. After a mean follow-up period of 7.3 years from the onset, proteinuria remains unchanged and renal function is well preserved in all the patients. In conclusion our series suggests that also in humans proteinuria and FSG might appear in solitary kidneys due to nephrectomy. This glomerular damage may result from the association of glomerular overload with other identified factors.