Autosomal recessive distal renal tubular acidosis (rdRTA) is characterised by severe hyperchloraemic metabolic acidosis in childhood, hypokalaemia, decreased urinary calcium solubility, and impaired bone physiology and growth. Two types of rdRTA have been differentiated by the presence or absence of sensorineural hearing loss, but appear otherwise clinically similar. Recently, we identified mutations in genes encoding two different subunits of the renal α-intercalated cell's apical H + -ATPase that cause rdRTA. Defects in the B1 subunit gene ATP6V1B1, and the a4 subunit gene ATP6V0A4, cause rdRTA with deafness and with preserved hearing, respectively. We have investigated 26 new rdRTA kindreds, of which 23 are consanguineous. Linkage analysis of seven novel SNPs and five polymorphic markers in, and tightly linked to, ATP6V1B1 and ATP6V0A4 suggested that four families do not link to either locus, providing strong evidence for additional genetic heterogeneity. In ATP6V1B1, one novel and five previously reported mutations were found in 10 kindreds. In 12 ATP6V0A4 kindreds, seven of 10 mutations were novel. A further nine novel ATP6V0A4 mutations were found in "sporadic" cases. The previously reported association between ATP6V1B1 defects and severe hearing loss in childhood was maintained. However, several patients with ATP6V0A4 mutations have developed hearing loss, usually in young adulthood. We show here that ATP6V0A4 is expressed within the human inner ear. These findings provide further evidence for genetic heterogeneity in rdRTA, extend the spectrum of disease causing mutations in ATP6V1B1 and ATP6V0A4, and show ATP6V0A4 expression within the cochlea for the first time.A cid-base regulation by the kidney is tightly controlled through the coupled processes of acid secretion and bicarbonate reabsorption via intercalated cells of the nephron's collecting duct segment. The result is regulated secretion into the urine of the net acid load provided by the human diet. The main proton pump responsible for urinary acidification by α-intercalated cells, the apical H + -ATPase, is a multi-subunit structure with a "head and stalk" configuration. The V 1 (head) and V 0 (membrane anchored) domains are responsible for ATP hydrolysis and transmembrane proton translocation respectively.

The aim of this prospective, multicenter study was to define the etiology and clinical features of acute kidney injury (AKI) in a pediatric patient cohort and to determine prognostic factors. Pediatric-modified RIFLE (pRIFLE) criteria were used to classify AKI. The patient cohort comprised 472 pediatric patients (264 males, 208 females), of whom 32.6% were newborns (median age 3 days, range 1-24 days), and 67.4% were children aged >1 month (median 2.99 years, range 1 month-18 years). The most common medical conditions were prematurity (42.2%) and congenital heart disease (CHD, 11.7%) in newborns, and malignancy (12.9%) and CHD (12.3%) in children aged >1 month. Hypoxic/ischemic injury and sepsis were the leading causes of AKI in both age groups. Dialysis was performed in 30.3% of newborns and 33.6% of children aged >1 month. Mortality was higher in the newborns (42.6 vs. 27.9%; p < 0.005). Stepwise multiple regression analysis revealed the major independent risk factors to be mechanical ventilation [relative risk (RR) 17.31, 95% confidence interval (95% CI) 4.88-61.42], hypervolemia (RR 12.90, 95% CI 1.97-84.37), CHD (RR 9.85, 95% CI 2.08-46.60), and metabolic acidosis (RR 7.64, 95% CI 2.90-20.15) in newborns and mechanical ventilation (RR 8.73, 95% CI 3.95-19.29), hypoxia (RR 5.35, 95% CI 2.26-12.67), and intrinsic AKI (RR 4.91, 95% CI 2.04-11.78) in children aged >1 month.

Genetic screening paradigms for congenital and infantile nephrotic syndrome are well established; however, screening in adolescents has received only minor attention. To help rectify this, we analyzed an unselected adolescent cohort of the international PodoNet registry to develop a rational screening approach based on 227 patients with nonsyndromic steroid-resistant nephrotic syndrome aged 10-20 years. Of these, 21% had a positive family history. Autosomal dominant cases were screened for WT1, TRPC6, ACTN4, and INF2 mutations. All other patients had the NPHS2 gene screened, and WT1 was tested in sporadic cases. In addition, 40 sporadic cases had the entire coding region of INF2 tested. Of the autosomal recessive and the sporadic cases, 13 and 6%, respectively, were found to have podocin-associated nephrotic syndrome, and 56% of them were compound heterozygous for the nonneutral p.R229Q polymorphism. Four percent of the sporadic and 10% of the autosomal dominant cases had a mutation in WT1. Pathogenic INF2 mutations were found in 20% of the dominant but none of the sporadic cases. In a large cohort of adolescents including both familial and sporadic disease, NPHS2 mutations explained about 7% and WT1 4% of cases, whereas INF2 proved relevant only in autosomal dominant familial disease. Thus, screening of the entire coding sequence of NPHS2 and exons 8-9 of WT1 appears to be the most rational and cost-effective screening approach in sporadic juvenile steroid-resistant nephrotic syndrome.

The aim of this study was to evaluate the impact of enuresis nocturna on quality of life of the mothers. Mothers who have a child with monosymptomatic nocturnal enuresis (n=28) and mothers who have a child without any health problems (n=38) were enrolled in the study. Groups were in balance for background variables (child's age, gender, and number of siblings; mother's age, marital status, highest year of education completed, and occupation; presence of health insurance; and type of residence). Short-Form Health Survey (SF-36) Questionnaire, the Beck Depression Inventory (BDI), and Spielberg's State-Trait Anxiety Inventory (STAI) were applied to all mothers. The mothers of children with enuresis had significantly lower quality-of-life scores in the SF-36 for the bodily pain (p=0.015) and role emotional (p=0.014) subscales. We observed significant difference between groups according to BDI; mean score was higher in mothers who have a child with enuresis nocturna (p=0.017). There was no significant difference between groups according to the STAI. Significant differences according to bodily pain and role emotional subscales of SF-36, and the BDI scores, show that the mothers were negatively affected by having a child with monosymptomatic nocturnal enuresis.

It is known that small alterations leading to different vitamin D receptor (VDR) alleles affect resistance or susceptibility to infections. In this study, we examined VDR gene polymorphisms in urinary tract infections (UTI), which are common and an important cause of morbidity in children and subsequently of renal scar formation. We evaluated 92 patients diagnosed with UTI and 105 children without prior history of UTI as a control group. The VDR gene polymorphisms BsmI, FokI, ApaI, and TaqI were evaluated in patients and controls. BsmI polymorphism genotype distribution was similar between groups. There was a significant difference between groups for FokI (p =0 < 001); for the ff genotype, the risk of UTI was significantly increased (p < 0.01) ,at 3.94 times higher (odds ratio = 3.94; 95% confidence interval 1.71-9.09). ApaI polymorphism was significantly increased in the control group (p < 0.01) and evaluated as a protective factor. Comparing the TaqI genotype between groups, there was no statistically significant difference, but in both Tt and tt genotypes, there was minimal increased risk of UTI. The results of this study suggest that VDR gene polymorphisms can be important for susceptibility to UTI and renal scar formation. Association between VDR polymorphisms and UTI is in accordance with the understanding of how vitamin D modulates the immune response against infections.

Renovascular disease accounts for 8-10% of all cases of paediatric hypertension, whereas, in adults, its incidence is approximately 1%. The Turkish Paediatric Hypertension Group aimed to create the first registry database for childhood renovascular hypertension in Turkey. Twenty of the 28 paediatric nephrology centres in Turkey responded to the survey and reported 45 patients (27 girls, 18 boys) with renovascular hypertension between 1990 and 2005. The age at presentation ranged from 20 days to 17 years. The mean blood pressure at the diagnosis was 169/110 mmHg. Chief complaints of symptomatic patients were headache (38%), seizure (18%), epistaxis (4%), growth retardation (4%), cognitive dysfunction (4%), polyuria (2%), palpitation (2%), and hemiplegia (2%). Renovascular hypertension was found incidentally in 11 children. The diagnosis of renovascular hypertension was established with conventional angiography in 39 patients, MR angiography in three, CT angiography in two, and captopril diethylene triamine penta-acetic acid (DTPA) scintigraphy in one patient. Twenty-one children had bilateral renal artery stenosis and 24 had unilateral renal artery stenosis. Of these, 14 (31%) had fibromuscular dysplasia; 12 (27%) Takayasu's arteritis; six (13%) neurofibromatosis; two (5%) Williams syndrome; one (2%) Kawasaki disease; one (2%) mid-aortic syndrome; one (2%) extrinsic compression to the renal artery, and eight (18%) unspecified bilateral renal artery stenosis. Hypertension was controlled with antihypertensive drugs in 17 patients. Percutaneous transluminal angioplasty (PTRA) or surgery had to be performed in 28 patients: PTRA in 16 patients, PTRA + surgery in one patient and surgery in 11 patients (four nephrectomies). The importance of vasculitic disease, especially Takayasu's arteritis, should not be underestimated in children with renovascular hypertension.

Enuresis nocturna is a common problem. Numerous etiologic factors have been investigated, and various theories have been proposed. The objectives of our study were to establish the differences in the sleep quality of nocturnal enuretic patients from that of healthy voluntary subjects, and the changes after treatment with desmopressin acetate (DDAVP), among primary school children. The study comprised 19 children with primary nocturnal enuresis and 32 healthy children in the control group. Subjective assessment of sleep was determined with the Pittsburgh Sleep Quality Index (PSQI) questionnaire. PSQI scores for each patient and control subject were determined before the study was started and after a month time interval. The sleep quality of the nocturnal enuretic children was poor. We found lower scores after a month's treatment with DDAVP, and significant differences in two dimensions in the patient group: 'subjective sleep quality' and 'sleep disturbances'. When we asked the patients' group what caused the sleep disturbance, they replied 'the fear or the anxiety of bedwetting during sleep'. This anxiety or fear seemed to be a factor that probably affected their sleep quality. So, active treatment (medical or behavioral) should be started as soon as the child is ready to receive it or when the enuretic child wants to be dry when asleep.

Micturating cystourethrogram (MCUG) is an imaging technique indicated in the diagnosis and follow-up of many diseases. We investigated the reliability and the efficacy of midazolam and chloral hydrate in sedation and anxiolysis during micturating cystourethrogram. Fifty-three children of similar ages (39 girls, 14 boys, mean age of 5.8+/-3.5 years) were randomized to midazolam (n=17), chloral hydrate (n=18) and control groups (n=18). Oral midazolam 0.6 mg/kg or chloral hydrate 25 mg/kg or saline were administered to the study groups 15-30 min prior to the urinary catheterization. Brietkopf and Buttner, Frankl and Houpt scales and Spielberger's State Anxiety Inventory and parent's impressions were used to assess the level of sedation and anxiety. The Brietkopf and Buttner classification of emotional status and Houpt behavior rating scale demonstrated a significantly better emotional status and sedation in the midazolam group when compared to controls (P=0.01 and P=0.018, respectively). The catheterization was described as a more unpleasant and distressing event by the parents of the control and the chloral hydrate groups when compared to the parents of the midazolam group (P<0.05). Bladder capacity and frequency of detection of residual urine were not statistically different between the three study groups (P>0.05). Vital signs did not change significantly in any child. Sedation with midazolam does not have adverse effects on the results of micturating cystourethrogram, while it reduces the discomfort in children undergoing this radiological technique.