長期経過を観察し得たIgA腎症を合併した腎性低尿酸血症の1例

抄録

We report a case of IgA nephropathy associated with renal hypouricemia. The patient's renal function had decreased gradually during the previous 15 years, resulting in chronic renal failure. Levels of serum uric acid and uric acid clearance were 1.0 mg/dl and 39.4 ml/min, respectively. Pyrazinamide suppression test indicated that the patent had defective tubular reabsorption of uric acid at the presecretory site. The serum uric acid level elevated linearly to 5.0 mg/dl during the 15-year period, in parallel with a change in serum creatinine level, giving a significantly positive correlation coefficient of 0.9776. The ratio of uric acid and creatinine clearances showed no significant change, although both decreased during the 15 years. These results were a different from those in patients with chronic glomerulonephri tis, including IgA nephropathy, where the serum uric acid level had shown no significant correlation with serum creatinine level above 2, 0 mg/dl and the ratio of uric acid clearanceand creatinine clearance had exponentially elevated after the latter decreased below 30-40 ml/min. The patient presented here has defective tubular transport of uric acid at the site of urate reabsorption, and appears to show a different tubular dysfunction response from patients with chronic glomerulonephritis and decreased renal function.