Sophie Taque

Recessive mutations in DGKE cause atypical hemolytic-uremic syndrome

Pathologic thrombosis is a major cause of mortality. Hemolytic-uremic syndrome (HUS) features episodes of small-vessel thrombosis resulting in microangiopathic hemolytic anemia, thrombocytopenia and renal failure. Atypical HUS (aHUS) can result from genetic or autoimmune factors that lead to pathologic complement cascade activation. Using exome sequencing, we identified recessive mutations in DGKE (encoding diacylglycerol kinase ɛ) that co-segregated with aHUS in nine unrelated kindreds, defining a distinctive Mendelian disease. Affected individuals present with aHUS before age 1 year, have persistent hypertension, hematuria and proteinuria (sometimes in the nephrotic range), and develop chronic kidney disease with age. DGKE is found in endothelium, platelets and podocytes. Arachidonic acid–containing diacylglycerols (DAG) activate protein kinase C (PKC), which promotes thrombosis, and DGKE normally inactivates DAG signaling. We infer that loss of DGKE function results in a prothrombotic state. These findings identify a new mechanism of pathologic thrombosis and kidney failure and have immediate implications for treating individuals with aHUS.

Prospective, Randomized Trial Comparing Short and Long Intravenous Antibiotic Treatment of Acute Pyelonephritis in Children: Dimercaptosuccinic Acid Scintigraphic Evaluation at 9 Months

OBJECTIVE. We report a prospective, randomized, multicenter trial that compared the effect of 3 vs 8 days of intravenous ceftriaxone treatment on the incidence of renal scarring at 6 to 9 months of follow-up in 383 children with a first episode of acute pyelonephritis. METHODS. After initial treatment with intravenous netilmicin and ceftriaxone, patients were randomly assigned to either 5 days of oral antibiotics (short intravenous treatment) or 5 days of intravenous ceftriaxone (long intravenous treatment). Inclusion criteria were age 3 months to 16 years and first acute pyelonephritis episode, defined by fever of >38.5°C, C-reactive protein level of >20 mg/L, and bacteriuria at >105/mL. All patients underwent 99m technetium-dimercaptosuccinic acid scintigraphy 6 to 9 months after inclusion. A total of 548 children were included, 48 of whom were secondarily excluded and 117 of whom were lost to follow-up or had incomplete data; therefore, 383 children were eligible, 205 of them in the short intravenous treatment group and 178 in the long intravenous treatment group. RESULTS. At inclusion, median age was 15 months, median duration of fever was 43 hours, and median C-reactive protein level was 122 mg/L. A total of 37% (143 of 383) of patients had a vesicoureteral reflux grades 1 to 3. Patient characteristics at inclusion were similar in both groups, except for a significantly higher proportion of girls in the short intravenous treatment group. The frequency of renal scars at scintigraphy was similar in both groups. Multivariate analysis demonstrated that renal scars were significantly associated with increased renal height at initial ultrasound and with the presence of grade 3 vesicoureteric reflux. CONCLUSIONS. The incidence of renal scars was similar in patients who received 3 days compared 8 days of intravenous ceftriaxone. Increased renal height at initial ultrasound examination and grade 3 vesicoureteric reflux were significant risk factors for renal scars.

Effect of conservative treatment on the renal outcome of children with primary hyperoxaluria type 1

Primary hyperoxaluria type 1 results from alanine:glyoxylate aminotransferase deficiency. Due to genotype/phenotype heterogeneity in this autosomal recessive disorder, the renal outcome is difficult to predict in these patients and the long-term impact of conservative management in children is unknown. We report here a multicenter retrospective study on the renal outcome in 27 affected children whose biological diagnosis was based on either decreased enzyme activity or identification of mutations in the patient or his siblings. The median age at first symptoms was 2.4 years while that at initiation of conservative treatment was 4.1 years; 6 children were diagnosed upon family screening. The median follow-up was 8.7 years. At diagnosis, 15 patients had an estimated glomerular filtration rate (eGFR) below 90, and 7 children already had stage 2-3 chronic kidney disease. The median baseline eGFR was 74, which rose to 114 with management in the 22 patients who did not require renal replacement therapy. Overall, 20 patients had a stable eGFR, however, 7 exhibited a decline in eGFR of over 20 during the study period. In a Cox regression model, the only variable significantly associated with deterioration of renal function was therapeutic delay with a relative risk of 1.7 per year. Our study strongly suggests that early and aggressive conservative management may preserve renal function of compliant children with this disorder, thereby avoiding dialysis and postponing transplantation.

School Performance of Childhood Cancer Survivors: Mind the Teenagers!

OBJECTIVE To assess school performance in an unselected group of childhood cancer survivors and study risk factors for impairment. STUDY DESIGN Rates of repeating a grade were compared for patients with cancer, their siblings, and the general population. Phone questionnaires were administered to patients about the school career of their child in remission and their siblings. Responses about cancer survivors were compared with those concerning their siblings and various registries provided by the national board of education. The primary outcome was the rate of repeating a grade. RESULTS A total of 148 children in remission with a mean age of 15 ± 5.3 years and a mean follow-up period since diagnosis of 6.3 ± 1.3 years were included. More patients than siblings repeated a grade (33% versus 21%; P = .02), with a mean delay since diagnosis of 2 years. Risk factors were an older age at diagnosis, attending a secondary school, low education level of parents, bone marrow transplantation, cerebral surgery, and physical sequelae. In multivariate analysis, risk for repeating was associated with low educational level of the father, attending secondary school at diagnosis, and requiring school-organized educational support on return to school. CONCLUSION After cancer, repeating a grade is not an exceptional occurrence, especially for teenagers; follow-up and supportive interventions before returning to school would be beneficial.

Central neurotoxicity of cyclosporine in two children with nephrotic syndrome

The central neurotoxicity of cyclosporin A (CsA) has been abundantly documented in pediatric and adult recipients of bone marrow or organ transplants, with variations in the rate of occurrence from 0.5% to 35%. We report two cases of central neurotoxicity ascribable to CsA in children with nephrotic syndrome due to lipoid nephrosis. The manifestations of CsA-related central neurotoxicity include confusion, aphasia, dystonias, akinetic mutism, parkinsonism, palsies, seizures, catatonia, coma, brain hemorrhage, and cortical blindness. Decreased density of the cerebral white matter is visible by computed tomography (CT) in 50% of cases, with the most commonly involved sites being the occipital cortex, the cerebellum, the periventricular substance, and the brainstem. Magnetic resonance imaging is more sensitive and more specific than CT for investigating the white matter. High-signal lesions are seen on T2-weighted sequences in the areas that are abnormal by CT. Many risk factors have been reported, including hypomagnesemia, hypocholesterolemia, high-dose glucocorticoid therapy, arterial hypertension, and infections. We present two patients with central neurotoxicity both of whom have elevated cholesterol levels.

TCF2/HNF-1beta mutations: 3 cases of fetal severe pancreatic agenesis or hypoplasia and multicystic renal dysplasia

The aim of this study was to document the association between pancreatic agenesis or hypoplasia and multicystic renal dysplasia related to transcription factor 2 (TCF2) or hepatocyte nuclear factor 1 beta mutations.

Diagnosis of fetal urinary tract malformations: prenatal management and postnatal outcome.

To evaluate prenatal management and to define the criteria of gravity for accurate assessment of the renal and overall prognosis of fetuses presenting malformations of the urinary tract.

Involvement of germline DDX1-MYCN duplication in inherited nephroblastoma.

This report concerns a 3-year-old girl with prenatal bilateral nephroblastomatosis and a family history of nephroblastoma. This girl had a chromosome 8 pericentric inversion inherited from her father. This inversion was observed in healthy individuals of the family and was absent in other individuals suffering from embryonic kidney tumor. We then supposed that another genetic anomaly predisposed her to tumorogenesis. Additional cryptic imbalances are reported in cases of apparently balanced chromosomal rearrangements with an abnormal phenotype. Array-CGH analysis showed a 569 kb duplication at 2p24.3 including the DDX1 and MYCN genes. This duplication was inherited from the patients father who also had a nephroblastoma. A link between germline MYCN duplication and the occurrence of other embryonic cancers such as neuroblastoma has already been described. We supposed that germline DDX1-MYCN duplication could also be involved in the apparition of nephroblastomas.

Renal failure in pediatric Castleman disease: Four French cases with thrombotic microangiopathy

Pediatric Castleman disease (CD) is an uncommon and poorly understood disorder of the lymph nodes. Renal failure has not been described in pediatric multicentric CD (MCD). We report four cases, who presented with polyadenopathy, organomegaly, edema and fluid accumulations, high blood pressure, and acute renal failure. In all cases, renal biopsy confirmed diffuse thrombotic microangiopathy. Definitive diagnosis of MCD was made by a biopsy of an affected lymph node located by computer tomography before initiation of corticosteroid therapy. Treatment of CD with corticosteroid therapy and rituximab was rapidly effective without relapse to date.

Treatment and outcome of congenital nephrotic syndrome

BACKGROUND Recommendations for management of Finnish-type congenital nephrotic syndrome (CNS) followed by many teams include daily albumin infusions, early bilateral nephrectomy, dialysis and transplantation. We aimed to assess the treatment and outcome of patients with CNS in France. METHODS We conducted a nationwide retrospective study on 55 consecutive children born between 2000 and 2014 treated for non-infectious CNS. RESULTS The estimated cumulative incidence of CNS was 0.5/100 000 live births. The underlying defect was biallelic mutations in NPHS1 (36/55, 65%), NPHS2 (5/55, 7%), PLCE1 (1/55, 2%), heterozygous mutation in WT1 (4/55, 7%) and not identified in nine children (16%). Fifty-three patients (96%) received daily albumin infusions from diagnosis (median age 14 days), which were spaced and withdrawn in 10 patients. Twenty children (35%) were managed as outpatients. Thirty-nine patients reached end-stage kidney disease (ESKD) at a median age of 11 months. The overall renal survival was 64% and 45% at 1 and 2 years of age, respectively. Thirteen children died during the study period including four at diagnosis, two of nosocomial catheter-related septic shock, six on dialysis and one after transplantation. The remaining 13 patients were alive with normal renal function at last follow-up [median 32 months (range 9-52)]. Renal and patient survivals were longer in patients with NPHS1 mutations than in other patients. The invasive infection rate was 2.41/patient/year. CONCLUSIONS Our study shows: (i) a survival free from ESKD in two-thirds of patients at 1 year and in one-half at 2 years and (ii) a significant reduction or even a discontinuation of albumin infusions allowing ambulatory care in a subset of patients. These results highlight the need for new therapeutic guidelines for CNS patients.