Hypercalciuria and nephrocalcinosis in the oculocerebrorenal syndrome.

The oculocerebrorenal (Lowe) syndrome is an X-linked recessive disorder characterized by congenital cataracts, hypotonia, developmental delay, poor growth and renal tubular dysfunction. Although the disorder has been mapped to chromosome Xq24-26, the underlying metabolic defect remains unknown. The renal component of the Lowe syndrome comprises tubular dysfunction, that is tubular proteinuria and generalized aminoaciduria progressing to the renal Fanconi syndrome, with later glomerular disease. Clinical problems typically include polyuria, acidosis, hypophosphatemia with rickets and eventually end stage renal disease. Hypercalciuria and its sequelae (nephrocalcinosis and nephrolithiasis) have not been described as cardinal features of the untreated disorder although they reportedly complicate vitamin D and calcium therapy of rickets. We discuss 5 boys with congenital cataracts, hypotonia, developmental delay, failure to thrive and the renal Fanconi syndrome who were diagnosed with the Lowe syndrome and in whom hypercalciuria was documented at diagnosis. We conclude that hypercalciuria and its sequelae may occur commonly in patients with the Lowe syndrome as a component of tubular dysfunction or a complication of therapy.

Peritoneal equilibration test curves and adequacy of dialysis in children on automated peritoneal dialysis.

Peritoneal equilibration tests (PETs) and adequacy studies have been performed to guide dialysis prescriptions in adult continuous ambulatory peritoneal dialysis patients, although few studies have been reported in pediatric patients on nightly cycling peritoneal dialysis. We performed 49 PETs in 28 children on automated peritoneal dialysis (mean age, 8.9 years; age range, 0.2 to 19.8 years; mean time on dialysis, 14.1 months) using Dianeal 2.5% dialysate (Baxter Healthcare Corp, McGaw Park, IL) inflow volumes of 1,200 mL/m2 (approximately 40 mL/kg), and standard technique. Mean 4-hour dialysate/plasma creatinine was 0.73 +/- 0.12 (range, 0.45 to 1.03). Mean 4-hour dialysate glucose/initial dialysate glucose was 0.28 +/- 0.10 (range, 0.06 to 0.50). Eighty percent of these PETs fell into the high average/high solute transport categories proposed by Twardowski, based on adult PETs. Twenty-four-hour dialysate collections were analyzed in 28 patients for protein loss and glucose absorption, as well as for calculation of weekly Kt/V. Mean weekly Kt/V was 1.94 +/- 0.94 (range, 0.63 to 5.10). Mean dialytic creatinine clearance calculated from the 4-hour dwell was 5.6 +/- 1.0 mL/min/1.73 m2 (56 L/wk/1.73 m2). Mean daily protein loss was 0.20 +/- 0.13 g/kg/d (range, 0.2 to 9.1 g/d) and glucose absorption was 3.49 +/- 2.24 g/kg/d (range, 17 to 196 g/d). Our results show higher solute diffusion rates in children compared with the published adult PET results (P = 0.0013 and P < 0.0001 for 4-hour creatinine and glucose results, respectively), with trends toward more rapid solute transport in younger compared with older children.(ABSTRACT TRUNCATED AT 250 WORDS)