A boy aged 5 years 9 months with Leber's congenital amaurosis and Dandy-Walker syndrome was referred for diagnostic evaluation of uremia and anemia. The patient presented with a 2-day history of progressive lethargy, facial swelling, and decreased urine output. On review, the parents noted insidious onset of polyuria and polydipsia for 1 year before presentation. An 18-month-old brother also had Leber's congenital amaurosis, Dandy-Walker syndrome, and polyuria.
On admission, the patient's blood pressure was 138/85 mm Hg; height, 100.3 cm (3.0 cm below SD); and weight, 15.6 kg (4.0 kg below SD). Significant laboratory data were as follows: serum potassium, 6.0 mmol/L; bicarbonate, 11 mmol/L; blood urea nitrogen, 32.5 mmol/L (91 mg/dL); creatinine, 630 μmol/L (7.1 mg/dL); ionized calcium, 0.69 mmol/L (normal, 1.13 to 1.37 mmol/L); phosphorus, 2.90 mmol/L (9.1 mg/dL); albumin, 42 g/L; hemoglobin, 46 g/L; hematocrit, 0.14; and reticulocyte index, 1.1. Examination of the urine revealed a specific