03 December 2008
A 43-year-old housewife had hypouricemia (serum uric acid ranging from 0.5 to 1.5 mg/dl; 30–89 µmol/l), increased uric acid clearance (47.6–83.0 ml/min), increased maximum tubular secretory capacity for para-aminohippurate, and idiopathic edema. Urate excretion was only minimally suppressed by pyrazinamide, and paradoxically decreased by probenecid. Uric acid clearance did not show any appreciable change after long-term administration of ticrynafen. In response to an increment of extracellular volume by hypertonic saline infusion or long-term 9α-fluorohydrocortisone administration, urate clearance did not show any substantial increase. These data may suggest that not only presecretory but possibly also postsecretory reabsorption of urate is impaired in this patient. No other renal tubular abnormalities were detected. Family study revealed that her renal hypouricemia is hereditary. She was unable to increase urinary excretion of sodium during hypertonic saline infusion and failed to change the response to the sodium-retaining action of 9oc-fluorohydrocortisone, presumably accounting for her edema.