FOCAL AND SEGMENTAL GLOMERULOSCLEROSIS AND PROTEINURIA ASSOCIATED WITH UNILATERAL RENAL AGENESIS

Abstract

Because reduction of renal mass (nephrectomy) can promote the development of focal gomerulosclerosis in animals, the possibility of patients with unilateral renal agenesis having similar lesions in the solitary kidney was investigated. The clinical course and pathologic findings of 8 patients who developed focal and segmental glomerulosclerosis (FGS) in their solitary kidneys are described. A review of 586 surgical pathology renal specimens (452 biopsies and 134 nephrectomies) revealed 29 (4.9%) cases of FGS; 5 also had unilateral renal agenesis (P = 2.1 .times. 10-7). In 9200 autopsies, 7 cases of unilateral renal agenesis were found; (29%) died of chronic renal failure with FGS lesions, and 5 did not have FGS. The 8th patient was identified because he was the father of a patient in this series. At the time of diagnosis the median age of the patients with unilateral renal agenesis and FGS was 25 yr; 7 of 8 were male. All had proteinuria; 4 had > 3 g/25 h (range, 1.2-9.0 g/24 h). Chronic renal failure developed in 6, and 4 died of their renal disease. Of the patients, 2 were related (father and son). One patient had clinical and morphologic evidence of reflux nephropathy. The glomerular lesions were characterized by focal and segmental scarring and adhesions in glomeruli, IgM and C3 deposition by immunofluorescence, and foot process loss and capillary loop collapse by EM. This series., although small, indicates that patients with unilateral renal agenesis are significantly more likely to develop FGS than patients with 2 kidneys. FGS did not develop after adult nephrectomy in 10 patients who died 8-46 yr after adult unilateral nephrectomy. The reason for this association was not established; these findings are in accord with experimental studies in which subtotal nephrectomy in young animals promotes FGS. In that setting and in these patients, glomerular damage may result from glomerular overload.