IgA Nephropathy in a Patient with Unilateral Renal Agenesis

Shinobu Waga, Department of Pediatrics, Hirosaki University School of Medicine, 5-Zaifucho, Hirosaki, 036 (Japan) Dear Sir, The clinical relevance of the observation that reduction of renal mass in rats promotes the development of proteinuria and progressive renal failure due to focal glomerular sclerosis (FGS) is controversial. Similar mechanisms were postulated in the patients with unilateral renal agenesis, oligomega-nephronia, or unilateral small kidney, but Novick et al. [ 1 ] suggestet that patients with a solitary kidney had an increased risk for progressive nephropathy after partial ne-phrectomy. These observations suggest that patients with a solitary kidney need further loss of nephrons in the remaining kidney due to resection or other structural abnormalities to be comparable to the rat model. Therefore, exposure of glomerulonephritis to a solitary kidney may also be relevant, but there have been few reports. Since IgA nephropathy is a disease with mesangial proliferation, which may cause progressive renal insuffici-cency, it is interesting to know how IgA nephropathy in a solitary kidney influences the outcome of renal function, and how the disease itself is influenced by a solitary kidney. We describe a boy with agenesis of the right kidney who had IgA nephropathy associated with nephrotic syndrome. A 9-year-old boy was found to have heavy proteinuria and hematuria on 27th July 1992. Proteinuria or hematuria had not been discovered by annual screening for uriniary abnormality at school in the previous 4 years. On admission, he weighed 28 kg and, within a short time, gained 5 kg. Blood pressure was 114/40 mm Hg. No skin or mucosal lesions were detected. His testes