Renal involvement in Down syndrome

Kidney disease has not been considered a frequent complication in Down syndrome (DS) patients; a variety of urological abnormalities and glomerulopathies have been reported in this population, and some DS patients develop chronic renal failure (CRF).The aim of this study was to improve the understanding of renal disease in patients with DS, focusing on the incidence and range of kidney and urological abnormalities in a population of DS patients. A cross-sectional study was carried out in DS patients referred from a pediatric genetics unit of a tertiary care center. Medical records were reviewed. A 24-h urine specimen and a blood sample were obtained. Fractional excretion of sodium and potassium, tubular reabsorption of phosphate, urinary excretion of calcium, magnesium, uric acid, creatinine clearance and proteinuria were determined. Ultrasound was performed to evaluate the kidneys and the urinary tract. Laboratory data were reviewed for any possible renal disorder. Sixty-nine patients, aged 12 months to 24 years, were recruited. Pathological findings included three cases of voiding disturbances and a case of hypertension in a 7-year old girl. Eight patients (11.6%) had hyperuricemia without gout. Eighteen patients (24.2%) had hyperuricosuria. Urinalysis revealed three cases of mild proteinuria and two patients with microscopic hematuria. Minor radiological abnormalities were found in five patients (7.3%). Three patients (4.5%) had CRF. Renal disease in patients with DS is not as rare as previously thought, although the majority of findings are of minor relevance. According to the variety of pathologies, and in order to detect early irreversible renal injury, it seems quite reasonable to perform regular monitoring of renal function in these patients.