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.

To investigate salt perception and discrimination and their possible association with blood pressure (BP), 72 healthy adolescents (42 boys) aged 9-21 years (mean 16.1 years) were studied. BP was measured with a standardized technique. Anthropometric measurement and conventional renal function tests were performed. Sensitivity tests to recognize the presence of salt when given simultaneously distilled/deionized water and a low sodium concentration water solution, and discrimination tests consisting of six graded samples of different saline solutions presented in randomized order were used to assess individual gustatory sensitivity. Average systolic BP values were 113.2±1.6 mmHg in boys and 109.6±1.9 mmHg in girls. Mean threshold level for salt sensitivity was 4.55±0.6 mmol/l. Systolic BP and salt sensitivity showed a significant correlation (r=−0.33, P<0.01) even when adjusting for weight. Discrimination score was correlated with salt sensitivity (r=0.27, P<0.05). There is a significant association between gustatory perception and BP in Spain adolescents, although a real cause-effect relationship has not been established.

Popular science has emphasized the risks of high sodium intake and many studies have confirmed that salt intake is closely related to hypertension. The present mini-review summarizes experiments about salt taste sensitivity and its relationship with blood pressure (BP) and other variables of clinical and familial relevance. Children and adolescents from control parents (N = 72) or with at least one essential hypertensive (EHT) parent (N = 51) were investigated. Maternal questionnaires on eating habits and vomiting episodes were collected. Offspring, anthropometric, BP, and salt taste sensitivity values were recorded and blood samples analyzed. Most mothers declared that they added "little salt" when cooking. Salt taste sensitivity was inversely correlated with systolic BP (SBP) in control youngsters (r = -0.33; P = 0.015). In the EHT group, SBP values were similar to control and a lower salt taste sensitivity threshold was found. Obese offspring of EHT parents showed higher SBP and C-reactive protein values but no differences in renin-angiotensin-aldosterone system activity. Salt taste sensitivity was correlated with SBP only in the nonobese EHT group (N = 41; r = 0.37; P = 0.02). Salt taste sensitivity was correlated with SBP in healthy, normotensive children and adolescents whose mothers reported significant vomiting during the first trimester (N = 18; r = -0.66; P < 0.005), but not in "non-vomiter offspring" (N = 54; r = -0.18; nonsignificant). There is evidence for a linkage between high blood pressure, salt intake and sensitivity, perinatal environment and obesity, with potential physiopathological implications in humans. This relationship has not been studied comprehensively using homogeneous methods and therefore more research is needed in this field.

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The purpose of this study was to investigate the relationship between salt taste perception and blood pressure (BP) in normotensive adolescents as modified by maternal fluid losses during the first trimester of gestation. Seventy-two healthy adolescents (42 boys) aged between 9.0-21.1 years, recruited from the population-based RICARDIN study, were included. A maternal questionnaire about the duration of pregnancy, birth weight and vomiting or diarrhoea in the first trimester of gestation was collected. The sample was categorized into: "vomiter descendents", those whose mother reported significant vomiting in the first trimester of gestation and "non-vomiter descendents" the remaining. Height, weight, and standardised BP measurement were recorded. Salt gustatory performance was assessed using a behavioral sensitivity test to determine the lower NaCl gustatory threshold, and a behavioral discrimination test, measuring the ability to distinguish among different saline solutions. Salt taste sensitivity showed a significant correlation with systolic BP (SBP) in "vomiter descendents" ( r = -0.66; P =0.003), but not in "non-vomiter descendents". Adjusted by gender, and actual height and weight, salt sensitivity performance remained significantly related to SBP. An association between descendents' SBP and maternal vomiting during gestation exists, adding a new element of evidence to the "Barker hypothesis".