Case 1. Patient 1 is a 60-year-old woman with polycystic kidney disease. By 1974 she had developed end-stage renal disease complicated by hypertension. Hemodialysis was required, and dialysis against a cuprophane membrane was carried out for 15 years through an arteriovenous fistula in the left arm.In 1981, mild diffuse bone pain developed. She also noted tingling and numbness in the left hand and fingers, which was worse in the morning. A diagnosis of carpal tunnel syndrome was made, and she was treated with splinting and nonsteroidal antiinflammatory agents. In 1985 at an outside hospital, she underwent surgical decompression of the median nerve in the left carpal tunnel. In 1986, she underwent a bone biopsy of the right iliac crest, and deferoxamine mesylate was prescribed for treatment of osteomalacia with aluminum deposition. Laboratory values at that time included a serum calcium of 10.4 mg/dl, a serum phosphorus of 3.2 mg/dl, and an alkaline phosphatase of 194 IUAiter (normal 16-95). Results of tests for antinuclear antibodies and rheumatoid factor were negative.From 1986 to 1987, the patient experienced chronic