This is the first report of maternal hypercalcemia caused by a CYP24A1 mutation, showing that not only infants are at risk for this complication. Our findings emphasize the importance of recognition, genetic diagnosis and proper treatment of this recently identified hypercalcemic disorder in this era of widespread vitamin D supplements.

Our findings support the applicability of VCD measurement in the estimation of hydration status in paediatric haemodialysis patients. The combination of clinical parameters and measurement of IVCD may enable more accurate evaluation of hydration of children on haemodialysis.

Urinary tract infection (UTI) differs between preterm and older infants and children in terms of prevalence, clinical presentation, causative organism, and rate of underlying renal anomalies. Data on risk factors of UTI in preterm infants are limited. The aim of this study was to characterize UTI both clinically and microbiologically in premature infants and to define possible risk factors and the role of breastfeeding in its development. This case-control study was conducted in a tertiary-care neonatal intensive care unit (NICU) between 1995 and 2003. The study group included all premature infants (<37 weeks' gestation) diagnosed with UTI. Pre-, peri-, and postnatal data on demographic, clinical, laboratory, and imaging variables were collected from the medical records and microbiology laboratory log and compared with a gestational age- and birth weight-matched infants without UTI (control group). The ratio of control infants to cases was 2:1. Of the 6198 premature infants admitted to the NICU during the study period, 56 (0.9%) were included in the study group. The main causative organism was Klebsiella spp. Logistic regression analysis identified gender [odds ratio (OR) 2.96, 95% confidence interval (CI) 1.28-6.85, P < 0.0001] and the presence of a peripheral intravenous catheter on the day of infection to be significantly associated with UTI, while breast milk was associated with a lower risk of infection (OR 0.314, 95% CI 0.140-0.707, P < 0.009).

New-onset post-transplantation food allergy has been described mainly after liver transplantation, and its pathogenesis was attributed to the immunomodulatory effects of tacrolimus therapy. The aim of the present study was to evaluate the association of food allergy with solid organ transplantation in our center. The medical records of children who underwent kidney transplantation and children who underwent liver or liver and kidney transplantation from 1986 to 2005 were reviewed. A total of 189 children (124 after kidney transplantation, 65 after liver or liver and kidney transplantation) received tacrolimus as part of the immunosuppressive regimen. New-onset post-transplantation food allergy was documented in four of them: two with liver transplants and two with combined kidney and liver transplants. The absence of new-onset food allergy in the children with isolated kidney transplants is compatible with other reports in the literature. This study supports the concept that the functioning liver itself, and not only tacrolimus immunosuppression, is a main contributor to food allergy in this patient population.

Seven patients aged 13 to 17.5 years developed acute renal failure after treatment with a variety of non-steroidal anti-inflammatory drugs (NSAID): naproxen, diclofenac, ibuprofen, dipyrone and paracetamol. Six of the patients used more than one kind of NSAID. None of the patients had previous history of renal disease or concomitant treatment with other drugs. The time interval between NSAID administration to the emergence of symptoms ranged from 1 to 4 days. The most common presenting symptoms were flank pain (4 patients), abdominal pain (3 patients) and vomiting (3 patients). All patients had normal urine output. Microscopic hematuria and proteinuria were found in 5 patients and leukocyturia in 2. Serum creatinine ranged from 1.3 to 8.3 mg% at presentation. Kidney biopsy was performed in 3 patients and showed findings consistent with mild interstitial inflammation in 1 patient, and normal renal tissue in 2. All patients were treated with intravenous fluids, 1 received corticosteroids. Renal function completely normalized in all patients within 7 to 16 days.

Vesicoureteral reflux (VUR) after a first episode of urinary tract infection (UTI) is apparently diagnosed much more frequently (25%-40%) in children than in neonates. The aims of the study were to determine the actual rate of VUR in neonates with UTI and to define the clinical clues to its diagnosis. The study sample included term infants with a diagnosis of UTI during their first month of life who were seen in this hospital between January 1997 and May 1999. All infants underwent complete diagnostic work-up (renal ultrasound and voiding cystourethrography [VCUG]). The medical files were reviewed for patient sex, age at UTI diagnosis, laboratory findings (including causative pathogen), and ultrasonographic findings. These parameters were correlated with the finding of VUR on VCUG. Sixty-four neonates (55 males, 9 females) with UTI were included in this study. UTI was 6 times more common in males than females, although the incidence of VUR was equal between the sexes (about 20%). The presence of VUR was associated with a significantly younger age at presentation of UTI (11.4+/-4 vs 16.9+/-6.6 days, p<0.01). VUR was diagnosed at a fourfold higher rate in neonates with Klebsiella-induced UTI compared to those with E. Coli-UTI. In 80% of those with significantly abnormal ultrasonographic findings VUR was found on VCUG. Jaundice was noted at UTI diagnosis 3 times more often in infants with VUR, and elevated creatinine level, 2.5 times more often.

Alterations in salivary Ca, P, Mg, U, Cr and intraoral pH levels were observed in the patient groups. DCS correlated with renal disease severity and therefore may be a reflection of other tissue calcification pathologies found in these patients.

Abnormal differentiation of the renal stem/progenitor pool into kidney tissue can lead to renal hypodysplasia (RHD), but the underlying causes of RHD are not well understood. In this multicenter study, we identified 20 Israeli pedigrees with isolated familial, nonsyndromic RHD and screened for mutations in candidate genes involved in kidney development, including PAX2, HNF1B, EYA1, SIX1, SIX2, SALL1, GDNF, WNT4, and WT1. In addition to previously reported RHD-causing genes, we found that two affected brothers were heterozygous for a missense variant in the WNT4 gene. Functional analysis of this variant revealed both antagonistic and agonistic canonical WNT stimuli, dependent on cell type. In HEK293 cells, WNT4 inhibited WNT3A induced canonical activation, and the WNT4 variant significantly enhanced this inhibition of the canonical WNT pathway. In contrast, in primary cultures of human fetal kidney cells, which maintain WNT activation and more closely represent WNT signaling in renal progenitors during nephrogenesis, this mutation caused significant loss of function, resulting in diminished canonical WNT/b-catenin signaling. In conclusion, heterozygous WNT4 variants are likely to play a causative role in renal hypodysplasia.