Publications by authors named "Jutta Gellermann"

38 Publications

Determinants of growth after kidney transplantation in prepubertal children.

Pediatr Nephrol 2021 Feb 23. Epub 2021 Feb 23.

Department of Pediatric Kidney, Liver and Metabolic Diseases, Children's Hospital, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.

Background: Short stature is a frequent complication after pediatric kidney transplantation (KT). Whether the type of transplantation and prior treatment with recombinant human growth hormone (GH) affects post-transplant growth, is unclear.

Methods: Body height, leg length, sitting height, and sitting height index (as a measure of body proportions) were prospectively investigated in 148 prepubertal patients enrolled in the CKD Growth and Development study with a median follow-up of 5.0 years. We used linear mixed-effects models to identify predictors for body dimensions.

Results: Pre-transplant Z scores for height (- 2.18), sitting height (- 1.37), and leg length (- 2.30) were reduced, and sitting height index (1.59) was increased compared to healthy children, indicating disproportionate short stature. Catch-up growth in children aged less than 4 years was mainly due to stimulated trunk length, and in older children to improved leg length, resulting in normalization of body height and proportions before puberty in the majority of patients. Use of GH in the pre-transplant period, congenital CKD, birth parameters, parental height, time after KT, steroid exposure, and transplant function were significantly associated with growth outcome. Although, unadjusted growth data suggested superior post-transplant growth after (pre-emptive) living donor KT, this was no longer true after adjusting for the abovementioned confounders.

Conclusions: Catch-up growth after KT is mainly due to stimulated trunk growth in young children (< 4 years) and improved leg growth in older children. Beside transplant function, steroid exposure and use of GH in the pre-transplant period are the main potentially modifiable factors associated with better growth outcome.
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http://dx.doi.org/10.1007/s00467-021-04922-2DOI Listing
February 2021

Precise variant interpretation, phenotype ascertainment, and genotype-phenotype correlation of children in the EARLY PRO-TECT Alport trial.

Clin Genet 2021 Jan 25;99(1):143-156. Epub 2020 Oct 25.

Clinic for Nephrology and Rheumatology, University Medical Center Göttingen, Göttingen, Germany.

Early initiation of therapy in patients with Alport syndrome (AS) slows down renal failure by many years. Genotype-phenotype correlations propose that the location and character of the individual's variant correlate with the renal outcome and any extra renal manifestations. In-depth clinical and genetic data of 60/62 children who participated in the EARLY PRO-TECT Alport trial were analyzed. Genetic variants were interpreted according to current guidelines and criteria. Genetically solved patients with X-linked inheritance were then classified according to the severity of their COL4A5 variant into less-severe, intermediate, and severe groups and disease progress was compared. Almost 90% of patients were found to carry (likely) pathogenic variants and classified as genetically solved cases. Patients in the less-severe group demonstrated a borderline significant difference in disease progress compared to those in the severe group (p = 0.05). While having only limited power according to its sample size, an obvious strength is the precise clinical and genetic data of this well ascertained cohort. As in published data differences in clinical progress were shown between patients with COL4A5 less-severe and severe variants. Therefore, clinical and segregational data are important for variant (re)classification. Genetic testing should be mandatory allowing early diagnosis and therapy of AS.
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http://dx.doi.org/10.1111/cge.13861DOI Listing
January 2021

A multicenter, randomized, placebo-controlled, double-blind phase 3 trial with open-arm comparison indicates safety and efficacy of nephroprotective therapy with ramipril in children with Alport's syndrome.

Kidney Int 2020 06 17;97(6):1275-1286. Epub 2020 Jan 17.

Department of Medical Statistics, University Medical Center Göttingen, Göttingen, Germany.

Children with Alport syndrome develop renal failure early in life. Since the safety and efficacy of preemptive nephroprotective therapy are uncertain we conducted a randomized, placebo-controlled, double-blind trial in 14 German sites of pediatric patients with ramipril for three to six years plus six months follow-up to determine these parameters. Pretreated children and those whose parents refused randomization became an open-arm control, which were compared to prospective real-world data from untreated children. The co-primary endpoints were safety (adverse drug reactions) and efficacy (time to progression). Out of 66 oligosymptomatic children, 22 were randomized and 44 joined the open-arm comparison. Ramipril therapy showed no safety issues (total of 216.4 patient-years on ramipril; adverse event rate-ratio 1.00; 95% confidence interval 0.66-1.53). Although not significant, our results cautiously showed that ramipril therapy was effective: in the randomized arm, Ramipril decreased the risk of disease progression by almost half (hazard ratio 0.51 (0.12-2.20)), diminished the slope of albuminuria progression and the decline in glomerular filtration. In adjusted analysis, indications of efficacy were supported by prospective data from participants treated open label compared with untreated children, in whom ramipril again seemed to reduce progression by almost half (0.53 (0.22-1.29)). Incorporating these results into the randomized data by Bayesian evidence synthesis resulted in a more precise estimate of the hazard-ratio of 0.52 (0.19-1.39). Thus, our study shows the safety of early initiation of therapy and supports the hope to slow renal failure by many years, emphasizing the value of preemptive therapy. Hence, screening programs for glomerular hematuria in children and young adults could benefit from inclusion of genetic testing for Alport-related gene-variants.
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http://dx.doi.org/10.1016/j.kint.2019.12.015DOI Listing
June 2020

Discontinuation of RAAS Inhibition in Children with Advanced CKD.

Clin J Am Soc Nephrol 2020 05 6;15(5):625-632. Epub 2020 Apr 6.

Division of Pediatric Nephrology, University Hospital Heidelberg, Heidelberg, Germany.

Background And Objectives: Although renin-angiotensin-aldosterone system inhibition (RAASi) is a cornerstone in the treatment of children with CKD, it is sometimes discontinued when kidney function declines. We studied the reasons of RAASi discontinuation and associations between RAASi discontinuation and important risk markers of CKD progression and on eGFR decline in the Cardiovascular Comorbidity in Children with CKD study.

Design, Setting, Participants, & Measurements: In this study, 69 children with CKD (67% male, mean age 13.7 years, mean eGFR 27 ml/min per 1.73 m) who discontinued RAASi during prospective follow-up were included. Initial change in BP, albuminuria, and potassium after discontinuation were assessed (median time 6 months). Rate of eGFR decline (eGFR slope) during a median of 1.9 years before and 1.2 years after discontinuation were estimated using linear mixed effects modeling.

Results: Physician-reported reasons for RAASi discontinuation were increase in serum creatinine, hyperkalemia, and symptomatic hypotension. After discontinuation of RAASi, BP and albuminuria increased, whereas potassium decreased. eGFR declined more rapidly after discontinuation of RAASi (-3.9 ml/min per 1.73 m per year; 95% confidence interval, -5.1 to -2.6) compared with the slope during RAASi treatment (-1.5 ml/min per 1.73 m per year; 95% confidence interval, -2.4 to -0.6; =0.005). In contrast, no change in eGFR slope was observed in a matched control cohort of patients in whom RAASi was continued.

Conclusions: Discontinuation of RAASi in children with CKD is associated with an acceleration of kidney function decline, even in advanced CKD.
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http://dx.doi.org/10.2215/CJN.09750819DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7269205PMC
May 2020

Twelve-month outcome in juvenile proliferative lupus nephritis: results of the German registry study.

Pediatr Nephrol 2020 07 19;35(7):1235-1246. Epub 2020 Mar 19.

Department of Paediatric Kidney, Liver and Metabolic Diseases, Paediatric Research Center, Hannover Medical School Children's Hospital, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.

Background: Children presenting with proliferative lupus nephritis (LN) are treated with intensified immunosuppressive protocols. Data on renal outcome and treatment toxicity is scare.

Methods: Twelve-month renal outcome and comorbidity were assessed in 79 predominantly Caucasian children with proliferative LN reported to the Lupus Nephritis Registry of the German Society of Paediatric Nephrology diagnosed between 1997 and 2015.

Results: At the time of diagnosis, median age was 13.7 (interquartile range 11.8-15.8) years; 86% showed WHO histology class IV, nephrotic range proteinuria was noted in 55%, and median estimated glomerular filtration rate amounted to 75 ml/min/1.73 m. At 12 months, the percentage of patients with complete and partial remission was 38% and 41%, respectively. Six percent of patients were non-responders and 15% presented with renal flare. Nephrotic range proteinuria at the time of diagnosis was associated with inferior renal outcome (odds ratio 5.34, 95% confidence interval 1.26-22.62, p = 0.02), whereas all other variables including mode of immune-suppressive treatment (e.g., induction treatment with cyclophosphamide (IVCYC) versus mycophenolate mofetil (MMF)) were not significant correlates. Complications were reported in 80% of patients including glucocorticoid toxicity in 42% (Cushingoid appearance, striae distensae, cataract, or osteonecrosis), leukopenia in 37%, infection in 23%, and menstrual disorder in 20%. Growth impairment, more pronounced in boys than girls, was noted in 78% of patients.

Conclusions: In this cohort of juvenile proliferative LN, renal outcome at 12 months was good irrespectively if patients received induction treatment with MMF or IVCYC, but glucocorticoid toxicity was very high underscoring the need for corticoid sparing protocols. Graphical abstract.
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http://dx.doi.org/10.1007/s00467-020-04501-xDOI Listing
July 2020

Whole exome sequencing identified ATP6V1C2 as a novel candidate gene for recessive distal renal tubular acidosis.

Kidney Int 2020 03 22;97(3):567-579. Epub 2019 Oct 22.

Division of Nephrology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA. Electronic address:

Distal renal tubular acidosis is a rare renal tubular disorder characterized by hyperchloremic metabolic acidosis and impaired urinary acidification. Mutations in three genes (ATP6V0A4, ATP6V1B1 and SLC4A1) constitute a monogenic causation in 58-70% of familial cases of distal renal tubular acidosis. Recently, mutations in FOXI1 have been identified as an additional cause. Therefore, we hypothesized that further monogenic causes of distal renal tubular acidosis remain to be discovered. Panel sequencing and/or whole exome sequencing was performed in a cohort of 17 families with 19 affected individuals with pediatric onset distal renal tubular acidosis. A causative mutation was detected in one of the three "classical" known distal renal tubular acidosis genes in 10 of 17 families. The seven unsolved families were then subjected to candidate whole exome sequencing analysis. Potential disease causing mutations in three genes were detected: ATP6V1C2, which encodes another kidney specific subunit of the V-type proton ATPase (1 family); WDR72 (2 families), previously implicated in V-ATPase trafficking in cells; and SLC4A2 (1 family), a paralog of the known distal renal tubular acidosis gene SLC4A1. Two of these mutations were assessed for deleteriousness through functional studies. Yeast growth assays for ATP6V1C2 revealed loss-of-function for the patient mutation, strongly supporting ATP6V1C2 as a novel distal renal tubular acidosis gene. Thus, we provided a molecular diagnosis in a known distal renal tubular acidosis gene in 10 of 17 families (59%) with this disease, identified mutations in ATP6V1C2 as a novel human candidate gene, and provided further evidence for phenotypic expansion in WDR72 mutations from amelogenesis imperfecta to distal renal tubular acidosis.
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http://dx.doi.org/10.1016/j.kint.2019.09.026DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7039771PMC
March 2020

Generation and Validation of a Limited Sampling Strategy to Monitor Mycophenolic Acid Exposure in Children With Nephrotic Syndrome.

Ther Drug Monit 2019 12;41(6):696-702

Pediatric Nephrology, Children's and Adolescents' Hospital, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne.

Background: Mycophenolate mofetil (MMF) plays an increasingly important role in the treatment of children with nephrotic syndrome, especially in steroid sparing protocols. Recent publications show the relationship of exposure to its active moiety mycophenolic acid (MPA) and clinical efficacy. Performance of full-time pharmacokinetic (PK) profiles, however, is inconvenient and laborious. Established limited sampling strategies (LSS) to estimate the area under the concentration (AUC) versus time curve of MPA (MPA-AUC) in pediatric renal transplant recipients cannot be easily transferred to children suffering from nephrotic syndrome, mainly because of the lack of concomitant immunosuppressive therapy. We therefore aimed for the generation and validation of a LSS to estimate MPA exposure to facilitate therapeutic drug monitoring in children with nephrotic syndrome.

Methods: We performed 27 complete PK profiles in 23 children in remission [mean age (±SD):12.3 ± 4.26 years] to generate and validate an LSS. Sampling time points were before administration (C0) and 0.5, 1, 1.5, 2, 4, 6, 8, and 12 hours after the administration of MMF. MPA was measured by enzyme multiplied immunoassay technique. There was no concomitant treatment with calcineurin inhibitors.

Results: Mean daily dose of MMF was 927 ± 209 mg/m of body surface area resulting in a mean MPA-AUC0-12 value of 59.2 ± 29.3 mg × h/L and a predose level of 3.03 ± 2.24 mg/L. Between-patient variability of dose-normalized MPA-AUC0-12 was high (coefficient of variation: 45.5%). Correlation of predose levels with the corresponding MPA-AUC0-12 was moderate (r = 0.59) in a subgroup of 18 patients (20 PK profiles, generation group). An algorithm based on 3 PK sampling time points during the first 2 hours after MMF dosing (estimated AUC0-12 = 8.7 + 4.63 × C0 + 1.90 × C1 + 1.52 × C2) was able to predict MPA-AUC with a low percentage prediction error (3.88%) and a good correlation of determination (r = 0.90). Validation of this algorithm in a randomized separate group of 6 patients (7 PK profiles, validation group) resulted in comparably good correlation (r = 0.95) and low percentage prediction error (5.57%).

Conclusions: An abbreviated profile within the first 2 hours after MMF dosing gives a good estimate of MPA exposure in children with nephrotic syndrome and hence has the potential to optimize MMF therapy.
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http://dx.doi.org/10.1097/FTD.0000000000000671DOI Listing
December 2019

Low levels of urinary epidermal growth factor predict chronic kidney disease progression in children.

Kidney Int 2019 07 20;96(1):214-221. Epub 2019 Mar 20.

Division of Pediatric Nephrology, Center for Pediatrics and Adolescent Medicine, Heidelberg University Hospital, Heidelberg, Germany. Electronic address:

Urinary epidermal growth factor (uEGF) has recently been identified as a promising biomarker of chronic kidney disease (CKD) progression in adults with glomerular disease. Low levels of uEGF predict CKD progression and appear to reflect the extent of tubulointerstitial damage. We investigated the relevance of uEGF in pediatric CKD. We performed a post hoc analysis of the Cardiovascular Comorbidity in Children with CKD (4C) study, which prospectively follows children aged 6-17 years with baseline estimated glomerular filtration rate (eGFR) of 10-60 ml/min/1.73 m. uEGF levels were measured in archived urine collected within 6 months of enrollment. Congenital abnormalities of the kidney and urinary tract were the most common cause of CKD, with glomerular diseases accounting for <10% of cases. Median eGFR at baseline was 28 ml/min/1.73 m, and 288 of 623 participants (46.3%) reached the composite endpoint of CKD progression (50% eGFR loss, eGFR < 10 ml/min/1.73 m, or initiation of renal replacement therapy). In a Cox proportional hazards model, higher uEGF/Cr was associated with a decreased risk of CKD progression (HR 0.76; 95% CI 0.69-0.84) independent of age, sex, baseline eGFR, primary kidney disease, proteinuria, and systolic blood pressure. The addition of uEGF/Cr to a model containing these variables resulted in a significant improvement in C-statistics, indicating better prediction of the 1-, 2- and 3-year risk of CKD progression. External validation in a prospective cohort of 222 children with CKD demonstrated comparable results. Thus, uEGF may be a useful biomarker to predict CKD progression in children with CKD.
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http://dx.doi.org/10.1016/j.kint.2019.01.035DOI Listing
July 2019

Treatment and long-term outcome in primary distal renal tubular acidosis.

Nephrol Dial Transplant 2019 06;34(6):981-991

Department of Paediatric Nephrology, Great Ormond Street Hospital for Children, NHS Foundation Trust, London, UK.

Background: Primary distal renal tubular acidosis (dRTA) is a rare disorder, and we aimed to gather data on treatment and long-term outcome.

Methods: We contacted paediatric and adult nephrologists through European professional organizations. Responding clinicians entered demographic, biochemical, genetic and clinical data in an online form.

Results: Adequate data were collected on 340 patients (29 countries, female 52%). Mutation testing had been performed on 206 patients (61%); pathogenic mutations were identified in 170 patients (83%). The median (range) presentation age was 0.5 (0-54) years and age at last follow-up was 11.0 (0-70.0) years. Adult height was slightly below average with a mean (SD score) of -0.57 (±1.16). There was an increased prevalence of chronic kidney disease (CKD) Stage ≥2 in children (35%) and adults (82%). Nephrocalcinosis was reported in 88%. Nephrolithiasis was more common with SLC4A1 mutations (42% versus 21%). Thirty-six percent had hearing loss, particularly in ATP6V1B1 (88%). The median (interquartile range) prescribed dose of alkali (mEq/kg/day) was 1.9 (1.2-3.3). Adequate metabolic control (normal plasma bicarbonate and normocalciuria) was achieved in 158 patients (51%), more commonly in countries with higher gross domestic product (67% versus 23%), and was associated with higher height and estimated glomerular filtration rate.

Conclusion: Long-term follow-up from this large dRTA cohort shows an overall favourable outcome with normal adult height for most and no patient with CKD Stage 5. However, 82% of adult patients have CKD Stages 2-4. Importance of adequate metabolic control was highlighted by better growth and renal function but was achieved in only half of patients.
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http://dx.doi.org/10.1093/ndt/gfy409DOI Listing
June 2019

Familial Xp11.22 microdeletion including SHROOM4 and CLCN5 is associated with intellectual disability, short stature, microcephaly and Dent disease: a case report.

BMC Med Genomics 2019 01 10;12(1). Epub 2019 Jan 10.

Institute of Medical Genetics and Human Genetics, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.

Background: Two interstitial microdeletions Xp11.22 including the CLCN5 and SHROOM4 genes were recently reported in a male individual affected with Dent disease, short stature, psychomotor delay and minor facial anomalies. Dent disease, characterized by a specific renal phenotype, is caused by truncating mutations of CLCN5 in the majority of affected cases.

Case Presentation: Here, we present clinical and molecular findings in a male patient with clinical signs of Dent disease, developmental delay, short stature, microcephaly, and facial dysmorphism. Using molecular karyotyping we identified a hemizygous interstitial microdeletion Xp11.23p.11.22 of about 700 kb, which was inherited from his asymptomatic mother. Among the six deleted genes is CLCN5, which explains the renal phenotype in our patient. SHROOM4, which is partially deleted in this patient, is involved in neuronal development and was shown to be associated with X-linked intellectual disability. This is a candidate gene, the loss of which is thought to be associated with his further clinical manifestations. To rule out mutations in other genes related to intellectual disability, whole exome sequencing was performed. No other pathogenic variants that could explain the phenotypic features, were found.

Conclusion: We compared the clinical findings of the patient presented here with the reported case with an Xp11.22 microdeletion including CLCN5 and SHROOM4 and re-defined the phenotypic spectrum associated with this microdeletion.
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http://dx.doi.org/10.1186/s12920-018-0471-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6327553PMC
January 2019

Initial treatment of steroid-sensitive idiopathic nephrotic syndrome in children with mycophenolate mofetil prednisone: protocol for a randomised, controlled, multicentre trial (INTENT study).

BMJ Open 2018 10 10;8(10):e024882. Epub 2018 Oct 10.

Department of Pediatrics, University Children's Hospital Köln, University Hospital Köln, Köln, Germany.

Introduction: Idiopathic nephrotic syndrome is the most common glomerular disease in childhood with an incidence of 1.8 cases per 100 000 children in Germany. The treatment of the first episode implies two aspects: induction of remission and sustainment of remission. The recent Kidney Disease Improving Global Outcomes, American Academy of Pediatrics and German guidelines for the initial treatment of the first episode of a nephrotic syndrome recommend a 12-week course of prednisone. Despite being effective, this treatment is associated with pronounced glucocorticoid-associated toxicity due to high-dose prednisone administration over a prolonged period of time. The aim of the INTENT study (Initial treatment of steroid-sensitive idiopathic nephrotic syndrom in children with mycophenolate mofetil versus prednisone: protocol for a randomised, controlled, multicentre trial) is to show that an alternative treatment regimen with mycophenolic acid is not inferior regarding sustainment of remission, but with lower toxicity compared with treatment with glucocorticoids only.

Methods And Design: The study is designed as an open, randomised, controlled, multicentre trial. 340 children with a first episode of steroid-sensitive nephrotic syndrome and who achieved remission by a standard prednisone regimen will be enrolled in the trial and randomised to one of two treatment arms. The standard care group will be treated with prednisone for a total of 12 weeks; in the experimental group the treatment is switched to mycophenolate mofetil, also for a total of 12 weeks in treatment duration. The primary endpoint is the occurrence of a treated relapse within 24 months after completion of initial treatment.

Ethics And Dissemination: Ethics approval for this trial was granted by the ethics committee of the Medical Faculty of the University of Heidelberg (AFmu-554/2014). The study results will be published in accordance with the Consolidated Standards of Reporting Trials statement and the Standard Protocol Items: Recommendations for Interventional Trials guidelines. Our findings will be submitted to major international paediatric nephrology and general paediatric conferences and submitted for publication in a peer-reviewed, open-access journal.

Trial Registration Number: DRKS0006547; EudraCT2014-001991-76; Pre-result.

Date Of Registration: 30 October 2014; 24 February 2017.
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http://dx.doi.org/10.1136/bmjopen-2018-024882DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6252704PMC
October 2018

Presentation of pediatric Henoch-Schönlein purpura nephritis changes with age and renal histology depends on biopsy timing.

Pediatr Nephrol 2018 02 5;33(2):277-286. Epub 2017 Oct 5.

Department of General Pediatrics, Adolescent Medicine and Neonatology, Medical Center, University of Freiburg Faculty of Medicine, University of Freiburg, Mathildenstrasse 1, 79106, Freiburg, Germany.

Background: This study correlates the clinical presentation of Henoch-Schönlein purpura nephritis (HSPN) with findings on initial renal biopsy.

Methods: Data from 202 pediatric patients enrolled in the HSPN registry of the German Society of Pediatric Nephrology reported by 26 centers between 2008 and 2014 were analyzed. All biopsy reports were re-evaluated for the presence of cellular crescents or chronic pathological lesions (fibrous crescents, glomerular sclerosis, tubular atrophy >5%, and interstitial fibrosis >5%).

Results: Patients with HSPN with cellular glomerular crescents were biopsied earlier after onset of nephritis (median 24 vs 36 days, p = 0.04) than those without, whereas patients with chronic lesions were biopsied later (57 vs 19 days, p < 0.001) and were older (10.3 vs 8.6 years, p = 0.01) than those without. Patients biopsied more than 30 days after the onset of HSPN had significantly more chronic lesions (52 vs 22%, p < 0.001), lower eGFR (88 vs 102 ml/min/1.73m, p = 0.01), but lower proteinuria (2.3 vs 4.5 g/g, p < 0.0001) than patients biopsied earlier. Children above 10 years of age had lower proteinuria (1.98 vs 4.58 g/g, p < 0.001), lower eGFR (86 vs 101 ml/min/1.73m, p = 0.002) and were biopsied significantly later after onset of nephritis (44 vs 22 days, p < 0.001) showing more chronic lesions (45 vs 30%, p = 0.03). Proteinuria and renal function at presentation decreased with age.

Conclusions: In summary, we find an age-dependent presentation of HSPN with a more insidious onset of non-nephrotic proteinuria, impaired renal function, longer delay to biopsy, and more chronic histopathological lesions in children above the age of 10 years. Thus, HSPN presents more like Immunoglobulin A (IgA) nephritis in older than in younger children.
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http://dx.doi.org/10.1007/s00467-017-3794-1DOI Listing
February 2018

Association of Serum Soluble Urokinase Receptor Levels With Progression of Kidney Disease in Children.

JAMA Pediatr 2017 11 6;171(11):e172914. Epub 2017 Nov 6.

Department of Medicine, Rush University Medical Center, Chicago, Illinois.

Importance: Conventional methods to diagnose and monitor chronic kidney disease (CKD) in children, such as creatinine level and cystatin C-derived estimated glomerular filtration rate (eGFR) and assessment of proteinuria in spot or timed urine samples, are of limited value in identifying patients at risk of progressive kidney function loss. Serum soluble urokinase receptor (suPAR) levels strongly predict incident CKD stage 3 in adults.

Objective: To determine whether elevated suPAR levels are associated with renal disease progression in children with CKD.

Design, Setting, And Participants: Post hoc analysis of 2 prospectively followed up pediatric CKD cohorts, ie, the ESCAPE Trial (1999-2007) and the 4C Study (2010-2016), with serum suPAR level measured at enrollment and longitudinal eGFR measured prospectively. In the 2 trials, a total of 898 children were observed at 30 (ESCAPE Trial; n = 256) and 55 (4C Study; n = 642) tertiary care hospitals in 13 European countries. Renal diagnoses included congenital anomalies of the kidneys and urinary tract (n = 637 [70.9%]), tubulointerstitial nephropathies (n = 92 [10.2%]), glomerulopathies (n = 69 [7.7%]), postischemic CKD (n = 42 [4.7%]), and other CKD (n = 58 [6.5%]). Total follow-up duration was up to 7.9 years, and median follow-up was 3.1 years. Analyses were conducted from October 2016 to December 2016.

Exposures: Serum suPAR level was measured at enrollment, and eGFR was measured every 2 months in the ESCAPE Trial and every 6 months in the 4C Study. The primary end point of CKD progression was a composite of 50% eGFR loss, eGFR less than 10 mL/min/1.73 m2, or initiation of renal replacement therapy.

Main Outcomes And Measures: The primary end point in this study was renal survival, defined as a composite of 50% loss of GFR that persisted for at least 1 month, the start of renal replacement therapy, or an eGFR less than 10 mL/min/1.73 m2.

Results: Of the 898 included children, 560 (62.4%) were male, and the mean (SD) patient age at enrollment was 11.9 (3.5) years. The mean (SD) eGFR was 34 (16) mL/min/1.73 m2. The 5-year end point-free renal survival was 64.5% (95% CI, 57.4-71.7) in children with suPAR levels in the lowest quartile compared with 35.9% (95% CI, 28.7-43.0) in those in the highest quartile (P < .001). By multivariable analysis, the risk of attaining the end point was higher in children with glomerulopathies and increased with age, blood pressure, proteinuria, and lower eGFR at baseline. In patients with baseline eGFR greater than 40 mL/min/1.73 m2, higher log-transformed suPAR levels were associated with a higher risk of CKD progression after adjustment for traditional risk factors (hazard ratio, 5.12; 95% CI, 1.56-16.7; P = .007).

Conclusions And Relevance: Patients with high suPAR levels were more likely to have progression of their kidney disease. Further studies should determine whether suPAR levels can identify children at risk for future CKD.
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http://dx.doi.org/10.1001/jamapediatrics.2017.2914DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6121753PMC
November 2017

Low renal but high extrarenal phenotype variability in Schimke immuno-osseous dysplasia.

PLoS One 2017 10;12(8):e0180926. Epub 2017 Aug 10.

Division of Pediatric Nephrology, Center for Pediatrics and Adolescent Medicine, University of Heidelberg, Heidelberg, Germany.

Schimke immuno-osseous dysplasia (SIOD) is a rare multisystem disorder with early mortality and steroid-resistant nephrotic syndrome (SRNS) progressing to end-stage kidney disease. We hypothesized that next-generation gene panel sequencing may unsurface oligosymptomatic cases of SIOD with potentially milder disease courses. We analyzed the renal and extrarenal phenotypic spectrum and genotype-phenotype associations in 34 patients from 28 families, the largest SMARCAL1-associated nephropathy cohort to date. In 11 patients the diagnosis was made unsuspectedly through SRNS gene panel testing. Renal disease first manifested at median age 4.5 yrs, with focal segmental glmerulosclerosis or minimal change nephropathy on biopsy and rapid progression to end-stage kidney disease (ESKD) at median age 8.7 yrs. Whereas patients diagnosed by phenotype more frequently developed severe extrarenal complications (cerebral ischemic events, septicemia) and were more likely to die before age 10 years than patients identified by SRNS-gene panel screening (88 vs. 40%), the subgroups did not differ with respect to age at proteinuria onset and progression to ESKD. Also, 10 of 11 children diagnosed unsuspectedly by Next Generation Sequencing were small at diagnosis and all showed progressive growth failure. Severe phenotypes were usually associated with biallelic truncating mutations and milder phenotypes with biallelic missense mutations. However, no genotype-phenotype correlation was observed for the renal disease course. In conclusion, while short stature is a reliable clue to SIOD in children with SRNS, other systemic features are highly variable. Our findings support routine SMARCAL1 testing also in non-syndromic SRNS.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0180926PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5552097PMC
October 2017

Long-Term Outcome of Steroid-Resistant Nephrotic Syndrome in Children.

J Am Soc Nephrol 2017 Oct 31;28(10):3055-3065. Epub 2017 May 31.

Division of Pediatric Nephrology, University Center for Pediatrics and Adolescent Medicine, Heidelberg, Germany;

We investigated the value of genetic, histopathologic, and early treatment response information in prognosing long-term renal outcome in children with primary steroid-resistant nephrotic syndrome. From the PodoNet Registry, we obtained longitudinal clinical information for 1354 patients (disease onset at >3 months and <20 years of age): 612 had documented responsiveness to intensified immunosuppression (IIS), 1155 had kidney biopsy results, and 212 had an established genetic diagnosis. We assessed risk factors for ESRD using multivariate Cox regression models. Complete and partial remission of proteinuria within 12 months of disease onset occurred in 24.5% and 16.5% of children, respectively, with the highest remission rates achieved with calcineurin inhibitor-based protocols. Ten-year ESRD-free survival rates were 43%, 94%, and 72% in children with IIS resistance, complete remission, and partial remission, respectively; 27% in children with a genetic diagnosis; and 79% and 52% in children with histopathologic findings of minimal change glomerulopathy and FSGS, respectively. Five-year ESRD-free survival rate was 21% for diffuse mesangial sclerosis. IIS responsiveness, presence of a genetic diagnosis, and FSGS or diffuse mesangial sclerosis on initial biopsy as well as age, serum albumin concentration, and CKD stage at onset affected ESRD risk. Our findings suggest that responsiveness to initial IIS and detection of a hereditary podocytopathy are prognostic indicators of favorable and poor long-term outcome, respectively, in children with steroid-resistant nephrotic syndrome. Children with multidrug-resistant sporadic disease show better renal survival than those with genetic disease. Furthermore, histopathologic findings may retain prognostic relevance when a genetic diagnosis is established.
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http://dx.doi.org/10.1681/ASN.2016101121DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5619960PMC
October 2017

Kidney transplantation fails to provide adequate growth in children with chronic kidney disease born small for gestational age.

Pediatr Nephrol 2017 03 21;32(3):511-519. Epub 2016 Oct 21.

Department of Pediatric Kidney, Liver and Metabolic Diseases, Children's Hospital, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625, Hannover, Germany.

Background: Children with chronic kidney disease are frequently born small for gestational age (SGA) and prone to disproportionately short stature. It is unclear how SGA affects growth after kidney transplantation (KTx).

Methods: Linear growth (height, sitting height, and leg length) was prospectively investigated in a cohort of 322 pediatric KTx recipients, with a mean follow-up of 4.9 years. Sitting height index (ratio of sitting height to total body height) was used to assess body proportions. Predictors of growth outcome in KTx patients with (n = 94) and without (n = 228) an SGA history were evaluated by the use of linear mixed-effects models.

Results: Mean z-scores for all linear body dimensions were lower in SGA compared with non-SGA patients (p < 0.001). SGA patients presented with higher target height deficit and degree of body disproportion (p < 0.001). The latter was mainly due to reduced leg growth during childhood. Pubertal trunk growth was diminished in SGA patients, and the pubertal growth spurt of legs was delayed in both groups, resulting in further impairment of adult height, which was more frequently reduced in SGA than in non-SGA patients (50 % vs 18 %, p < 0.001). Use of growth hormone treatment in the pre-transplant period, preemptive KTx, transplant function, and control of metabolic acidosis were the only potentially modifiable correlates of post-transplant growth in SGA groups. By contrast, living related KTx, steroid exposure, and degree of anemia proved to be correlates in non-SGA only.

Conclusions: In children born SGA, growth outcome after KTx is significantly more impaired and affected by different clinical parameters compared with non-SGA patients.
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http://dx.doi.org/10.1007/s00467-016-3503-5DOI Listing
March 2017

Long-term renal outcome in children with OCRL mutations: retrospective analysis of a large international cohort.

Nephrol Dial Transplant 2018 01;33(1):85-94

University College London, Institute of Child Health and Great Ormond Street Hospital for Children, National Health Service Trust, London, UK.

Background: Lowe syndrome (LS) and Dent-2 disease (DD2) are disorders associated with mutations in the OCRL gene and characterized by progressive chronic kidney disease (CKD). Here, we aimed to investigate the long-term renal outcome and identify potential determinants of CKD and its progression in children with these tubulopathies.

Methods: Retrospective analyses were conducted of clinical and genetic data in a cohort of 106 boys (LS: 88 and DD2: 18). For genotype-phenotype analysis, we grouped mutations according to their type and localization. To investigate progression of CKD we used survival analysis by Kaplan-Meier method using stage 3 CKD as the end-point.

Results: Median estimated glomerular filtration rate (eGFR) was lower in the LS group compared with DD2 (58.8 versus 87.4 mL/min/1.73 m2, P < 0.01). CKD stage II-V was found in 82% of patients, of these 58% and 28% had moderate-to-severe CKD in LS and DD2, respectively. Three patients (3%), all with LS, developed stage 5 of CKD. Survival analysis showed that LS was also associated with a faster CKD progression than DD2 (P < 0.01). On multivariate analysis, eGFR was dependent only on age (b = -0.46, P < 0.001). Localization, but not type of mutations, tended to correlate with eGFR. There was also no significant association between presence of nephrocalcinosis, hypercalciuria, proteinuria and number of adverse clinical events and CKD.

Conclusions: CKD is commonly found in children with OCRL mutations. CKD progression was strongly related to the underlying diagnosis but did not associate with clinical parameters, such as nephrocalcinosis or proteinuria.
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http://dx.doi.org/10.1093/ndt/gfw350DOI Listing
January 2018

Nephrin Contributes to Insulin Secretion and Affects Mammalian Target of Rapamycin Signaling Independently of Insulin Receptor.

J Am Soc Nephrol 2016 Apr 23;27(4):1029-41. Epub 2015 Sep 23.

Katz Family Drug Discovery Center, Division of Nephrology and Hypertension and Diabetes Research Institute, University of Miami Miller School of Medicine, Miami, Florida;

Nephrin belongs to a family of highly conserved proteins with a well characterized function as modulators of cell adhesion and guidance, and nephrin may have a role in metabolic pathways linked to podocyte and pancreatic β-cell survival. However, this role is incompletely characterized. In this study, we developed floxed nephrin mice for pancreatic β-cell-specific deletion of nephrin, which had no effect on islet size and glycemia. Nephrin deficiency, however, resulted in glucose intolerance in vivo and impaired glucose-stimulated insulin release ex vivo Glucose intolerance was also observed in eight patients with nephrin mutations compared with three patients with other genetic forms of nephrotic syndrome or nine healthy controls.In vitro experiments were conducted to investigate if nephrin affects autocrine signaling through insulin receptor A (IRA) and B (IRB), which are both expressed in human podocytes and pancreatic islets. Coimmunoprecipitation of nephrin and IRB but not IRA was observed and required IR phosphorylation. Nephrin per se was sufficient to induce phosphorylation of p70S6K in an phosphatidylinositol 3-kinase-dependent but IR/Src-independent manner, which was not augmented by exogenous insulin. These results suggest a role for nephrin as an independent modulator of podocyte and pancreatic β-cell nutrient sensing in the fasting state and the potential of nephrin as a drug target in diabetes.
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http://dx.doi.org/10.1681/ASN.2015020210DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4814188PMC
April 2016

Spectrum of steroid-resistant and congenital nephrotic syndrome in children: the PodoNet registry cohort.

Clin J Am Soc Nephrol 2015 Apr 29;10(4):592-600. Epub 2015 Jan 29.

Due to the number of contributing authors, the affiliations are provided in the Supplemental Material.

Background And Objectives: Steroid-resistant nephrotic syndrome is a rare kidney disease involving either immune-mediated or genetic alterations of podocyte structure and function. The rare nature, heterogeneity, and slow evolution of the disorder are major obstacles to systematic genotype-phenotype, intervention, and outcome studies, hampering the development of evidence-based diagnostic and therapeutic concepts. To overcome these limitations, the PodoNet Consortium has created an international registry for congenital nephrotic syndrome and childhood-onset steroid-resistant nephrotic syndrome.

Design, Setting, Participants, & Measurements: Since August of 2009, clinical, biochemical, genetic, and histopathologic information was collected both retrospectively and prospectively from 1655 patients with childhood-onset steroid-resistant nephrotic syndrome, congenital nephrotic syndrome, or persistent subnephrotic proteinuria of likely genetic origin at 67 centers in 21 countries through an online portal.

Results: Steroid-resistant nephrotic syndrome manifested in the first 5 years of life in 64% of the patients. Congenital nephrotic syndrome accounted for 6% of all patients. Extrarenal abnormalities were reported in 17% of patients. The most common histopathologic diagnoses were FSGS (56%), minimal change nephropathy (21%), and mesangioproliferative GN (12%). Mutation screening was performed in 1174 patients, and a genetic disease cause was identified in 23.6% of the screened patients. Among 14 genes with reported mutations, abnormalities in NPHS2 (n=138), WT1 (n=48), and NPHS1 (n=41) were most commonly identified. The proportion of patients with a genetic disease cause decreased with increasing manifestation age: from 66% in congenital nephrotic syndrome to 15%-16% in schoolchildren and adolescents. Among various intensified immunosuppressive therapy protocols, calcineurin inhibitors and rituximab yielded consistently high response rates, with 40%-45% of patients achieving complete remission. Confirmation of a genetic diagnosis but not the histopathologic disease type was strongly predictive of intensified immunosuppressive therapy responsiveness. Post-transplant disease recurrence was noted in 25.8% of patients without compared with 4.5% (n=4) of patients with a genetic diagnosis.

Conclusions: The PodoNet cohort may serve as a source of reference for future clinical and genetic research in this rare but significant kidney disease.
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http://dx.doi.org/10.2215/CJN.06260614DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4386250PMC
April 2015

Patterns of growth after kidney transplantation among children with ESRD.

Clin J Am Soc Nephrol 2015 Jan 28;10(1):127-34. Epub 2014 Oct 28.

Department of Pediatric Kidney, Liver and Metabolic Diseases, Children's Hospital, Hannover Medical School, Hannover, Germany;

Background And Objectives: Poor linear growth is a frequent complication of CKD. This study evaluated the effect of kidney transplantation on age-related growth of linear body segments in pediatric renal transplant recipients who were enrolled from May 1998 until August 2013 in the CKD Growth and Development observational cohort study.

Design, Setting, Participants, & Measurements: Linear growth (height, sitting height, arm and leg lengths) was prospectively investigated during 1639 annual visits in a cohort of 389 pediatric renal transplant recipients ages 2-18 years with a median follow-up of 3.4 years (interquartile range, 1.9-5.9 years). Linear mixed-effects models were used to assess age-related changes and predictors of linear body segments.

Results: During early childhood, patients showed lower mean SD scores (SDS) for height (-1.7) and a markedly elevated sitting height index (ratio of sitting height to total body height) compared with healthy children (1.6 SDS), indicating disproportionate stunting (each P<0.001). After early childhood a sustained increase in standardized leg length and a constant decrease in standardized sitting height were noted (each P<0.001), resulting in significant catch-up growth and almost complete normalization of sitting height index by adult age (0.4 SDS; P<0.01 versus age 2-4 years). Time after transplantation, congenital renal disease, bone maturation, steroid exposure, degree of metabolic acidosis and anemia, intrauterine growth restriction, and parental height were significant predictors of linear body dimensions and body proportions (each P<0.05).

Conclusions: Children with ESRD present with disproportionate stunting. In pediatric renal transplant recipients, a sustained increase in standardized leg length and total body height is observed from preschool until adult age, resulting in restoration of body proportions in most patients. Reduction of steroid exposure and optimal metabolic control before and after transplantation are promising measures to further improve growth outcome.
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http://dx.doi.org/10.2215/CJN.02180314DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4284405PMC
January 2015

Serum suPAR levels are modulated by immunosuppressive therapy of minimal change nephrotic syndrome.

Pediatr Nephrol 2014 Dec 17;29(12):2411-4. Epub 2014 Aug 17.

Department of Pediatric Nephrology, Charité Universitätsmedizin Berlin, Charité Children's Hospital, Augustenburger Platz 1, 13353, Berlin, Germany.

Background: Soluble urokinase-type plasminogen activator receptor (suPAR) could be a causative factor in idiopathic focal segmental glomerulosclerosis (FSGS). It is currently unknown to what extent suPAR levels could be affected by treatment with immunosuppressive drugs such as cyclosporin A (CsA) and mycophenolate mofetil (MMF). Treatment with CsA, but not MMF, is accompanied by nephrotoxicity, and since suPAR levels correlate with glomerular filtration rate (GFR), treatment with these drugs could indirectly modulate suPAR levels by their effect on renal function.

Methods: We measured suPAR levels in a recent prospective multicenter crossover trial comparing the efficacy of MMF and CsA in pediatric patients with minimal change disease (MCD) and frequently relapsing steroid-sensitive nephrotic syndrome (FR-SSNS). All patients had biopsy-proven MCD and normal renal function; they were treated with each drug for 1 year in a crossover study design. Serum suPAR levels were measured before and after 1 year of therapy with MMF (n = 40) and CsA (n = 35).

Results: The suPAR levels decreased after 1 year of treatment with MMF (p < 0.05). Conversely, suPAR levels increased after 1 year of treatment with CsA in the same patients (p = 0.01). These changes in suPAR levels were not correlated to the estimated glomerular filtration rate (eGFR) or changes in the GFR.

Conclusions: Data from this prospective randomized trial suggest that treatment with MMF and CsA is associated with different effects on suPAR levels in children with MCD and that these are independent of their effects on GFR.
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http://dx.doi.org/10.1007/s00467-014-2913-5DOI Listing
December 2014

Genotype-phenotype associations in WT1 glomerulopathy.

Kidney Int 2014 May 8;85(5):1169-78. Epub 2014 Jan 8.

Division of Pediatric Nephrology, Center for Pediatrics and Adolescent Medicine, University of Heidelberg, Heidelberg, Germany.

WT1 mutations cause a wide spectrum of renal and extrarenal manifestations. Here we evaluated disease prevalence, phenotype spectrum, and genotype-phenotype correlations of 61 patients with WT1-related steroid-resistant nephrotic syndrome relative to 700 WT1-negative patients, all with steroid-resistant nephrotic syndrome. WT1 patients more frequently presented with chronic kidney disease and hypertension at diagnosis and exhibited more rapid disease progression. Focal segmental glomerulosclerosis was equally prevalent in both cohorts, but diffuse mesangial sclerosis was largely specific for WT1 disease and was present in 34% of cases. Sex reversal and/or urogenital abnormalities (52%), Wilms tumor (38%), and gonadoblastoma (5%) were almost exclusive to WT1 disease. Missense substitutions affecting DNA-binding residues were associated with diffuse mesangial sclerosis (74%), early steroid-resistant nephrotic syndrome onset, and rapid progression to ESRD. Truncating mutations conferred the highest Wilms tumor risk (78%) but typically late-onset steroid-resistant nephrotic syndrome. Intronic (KTS) mutations were most likely to present as isolated steroid-resistant nephrotic syndrome (37%) with a median onset at an age of 4.5 years, focal segmental glomerulosclerosis on biopsy, and slow progression (median ESRD age 13.6 years). Thus, there is a wide range of expressivity, solid genotype-phenotype associations, and a high risk and significance of extrarenal complications in WT1-associated nephropathy. We suggest that all children with steroid-resistant nephrotic syndrome undergo WT1 gene screening.
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http://dx.doi.org/10.1038/ki.2013.519DOI Listing
May 2014

Birth parameters and parental height predict growth outcome in children with chronic kidney disease.

Pediatr Nephrol 2013 Dec 1;28(12):2335-41. Epub 2013 Sep 1.

Department of Pediatric Kidney, Liver and Metabolic Diseases, Children's Hospital, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.

Background: We analyzed the impact of birth parameters and parental height on long-term growth outcome in children with chronic kidney disease (CKD) stage 3-5.

Methods: Linear growth was prospectively investigated in 509 children, with a mean follow-up of 4.1 years. Growth outcome was categorized in (i) poor growth (PG): height standard deviation score (SDS) during follow-up < -2.0 and/or actual or previous growth hormone (GH) treatment, and (ii) good growth (GG): height SDS ≥ -2.0 and no need for GH. A multivariate binary logistic regression model was constructed for predictors of PG outcome.

Results: PG was observed in 55 % of patients. The rate of pre-term and small for gestational age birth was significantly higher in children with PG compared to GG (43.2 vs. 25.6 % and 36.8 vs. 18.9 %; p < 0.001). Children with PG had significantly lower average values for gestational age, birth weight, length, and head circumference, umbilical cord pH, Apgar scores, and parental height than children with GG. Birth length, umbilical cord pH, and parental height were significant independent predictors of PG outcome (sensitivity 72.8 %, specificity 69.3 %).

Conclusions: Birth parameters and parental height are independent predictors of growth outcome in children with CKD.
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http://dx.doi.org/10.1007/s00467-013-2604-7DOI Listing
December 2013

Mycophenolate mofetil versus cyclosporin A in children with frequently relapsing nephrotic syndrome.

J Am Soc Nephrol 2013 Oct 27;24(10):1689-97. Epub 2013 Jun 27.

Department of Pediatric Nephrology, Charité Universitätsmedizin Berlin CVK, Berlin, Germany;

The severe side effects of long-term corticosteroid or cyclosporin A (CsA) therapy complicate the treatment of children with frequently relapsing steroid-sensitive nephrotic syndrome (FR-SSNS). We conducted a randomized, multicenter, open-label, crossover study comparing the efficacy and safety of a 1-year treatment with mycophenolate mofetil (MMF; target plasma mycophenolic acid trough level of 1.5-2.5 µg/ml) or CsA (target trough level of 80-100 ng/ml) in 60 pediatric patients with FR-SSNS. We assessed the frequency of relapse as the primary endpoint and evaluated pharmacokinetic profiles (area under the curve [AUC]) after 3 and 6 months of treatment. More relapses per patient per year occurred with MMF than with CsA during the first year (P=0.03), but not during the second year (P=0.14). No relapses occurred in 85% of patients during CsA therapy and in 64% of patients during MMF therapy (P=0.06). However, the time without relapse was significantly longer with CsA than with MMF during the first year (P<0.05), but not during the second year (P=0.36). In post hoc analysis, patients with low mycophenolic acid exposure (AUC <50 µg⋅h/ml) experienced 1.4 relapses per year compared with 0.27 relapses per year in those with high exposure (AUC>50 µg⋅h/ml; P<0.05). There were no significant differences between groups with respect to BP, growth, lipid levels, or adverse events. However, cystatin clearance, estimated GFR, and hemoglobin levels increased significantly with MMF compared with CsA. These results indicate that MMF is inferior to CsA in preventing relapses in pediatric patients with FR-SSNS, but may be a less nephrotoxic treatment option.
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http://dx.doi.org/10.1681/ASN.2012121200DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3785276PMC
October 2013

Growth and maturation improvement in children on renal replacement therapy over the past 20 years.

Pediatr Nephrol 2013 Oct 25;28(10):2043-51. Epub 2013 May 25.

Department of Paediatric Kidney, Liver and Metabolic Diseases, Children's Hospital, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany.

Background: The attainment of normal growth and maturation remains a major challenge in the management of children and adolescents requiring renal replacement therapy (RRT).

Methods: We compared growth and maturation in 384 German children with RRT who were followed between 1998 and 2009 with 732 children who were enrolled in the European Dialysis and Transplant Association (EDTA) Registry from 1985 to 1988; of these children, 78 and 88 %, respectively, were transplanted.

Results: The data on the German patients included in the EDTA registry did not differ significantly from those of the patients from other European countries. Overall, the mean height standard deviation score (SDS) has improved over the past 20 years from -3.03 to -1.80 (p < 0.001). Until the age of 6 years, the difference in height SDS was not significant, whereas it improved significantly in adolescence (-3.40 vs. -1.52; p < 0.001). Significant improvements in the delay of the pubertal growth spurt, age at menarche, bone maturation and body mass index (BMI) were noted in the recent German group compared to the EDTA group (each p < 0.001).

Conclusions: Our findings demonstrate a marked improvement of growth and maturation in paediatric patients on RRT during the past 20 years.
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http://dx.doi.org/10.1007/s00467-013-2502-zDOI Listing
October 2013

Genetic screening in adolescents with steroid-resistant nephrotic syndrome.

Kidney Int 2013 Jul 20;84(1):206-13. Epub 2013 Mar 20.

Division of Pediatric Nephrology, Center for Pediatric and Adolescent Medicine, University of Heidelberg, Heidelberg, Germany.

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.
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http://dx.doi.org/10.1038/ki.2013.93DOI Listing
July 2013

Chronic kidney disease in adolescent and adult patients with phenylketonuria.

J Inherit Metab Dis 2013 Sep 9;36(5):747-56. Epub 2012 Nov 9.

Department of Pediatric Endocrinology, Gastroenterology and Metabolic Diseases, Charité Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany.

Objectives: A lifelong phenylalanine-restricted diet with supplementation of a phenylalanine-free amino acid formula is recommended in patients with phenylketonuria (PKU). The effect of a long-term PKU diet on renal function and blood pressure has not been investigated yet.

Design: We analyzed renal function in 67 patients with PKU, aged 15-43 years, by measuring glomerular filtration rate (GFR) and effective renal plasma flow by isotope clearance ((51)Cr-EDTA, (123)J-Hippuran), estimated GFR, blood retention parameters, urinary protein and electrolyte excretion. Renal ultrasound and 24 h ambulatory blood pressure monitoring were performed additionally. Patients were divided into three groups according to their: 1) current diet (CD), i.e., daily protein intake: ICD <0.8 g/kg, IICD 0.8-1.04 g/kg, IIICD >1.04 g/kg; 2) life-long diet time (LDT), i.e., cumulative years of life in which daily protein intake exceeded dietary recommendations: ILDT <15 years, IILDT 15-19 years, IIILDT >19 years.

Results: GFR was decreased in 19 % of the patients. With increasing protein intake, GFR decreased significantly (ICD 111 ml/min; IICD 105 ml/min; IIICD 99 ml/min. ILDT 112 ml/min; IILDT 103 ml/min; IIILDT 99 ml/min). Proteinuria was detected in 31 %, microalbuminuria in 7 %, and hypercalciuria in 23 % of the patients. 23 % of the patients had arterial hypertension, and 41 % revealed a nocturnal non-dipping status.

Conclusions: In patients with PKU on a lifelong diet we could detect impaired renal function in 19 %, proteinuria in 31 %, and arterial hypertension in 23 %. Thus, chronic kidney disease may develop in PKU patients, and routine renal function tests should be performed during long-term follow-up.
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http://dx.doi.org/10.1007/s10545-012-9548-0DOI Listing
September 2013

Long-term follow-up after rituximab for steroid-dependent idiopathic nephrotic syndrome.

Nephrol Dial Transplant 2012 May 9;27(5):1910-5. Epub 2011 Nov 9.

Pediatric Nephrology, University Children’s Hospital, Hamburg, Germany.

Background: In patients with refractory steroid-sensitive nephrotic syndrome (SSNS), treatment with rituximab has shown encouraging results; however, long-term follow-up data are not available.

Methods: We performed a retrospective analysis of 37 patients (25 boys) with steroid-dependent nephrotic syndrome who were treated with rituximab (375 mg/m(2) given weekly for one to four courses). Long-term follow-up data (>2 years, median 36, range 24-92.8 months) are available for 29 patients (12 boys).

Results: Twenty-six of 37 (70.3%) patients remained in remission after 12 months. Relapses occurred in 24 (64.8%) patients after a median of 9.6 (range 5.2-64.1) months. Time to first relapse was significantly shorter in patients receiving one or two compared to three or four initial infusions. In the 29 patients with long-term follow-up for >2 years, 12 (41%) patients remained in remission after the initial rituximab course for >24 months, 7 (24.1%) patients without further maintenance immunosuppression. Nineteen children received two to four repeated courses of rituximab increasing the total number of patients with long-term remission to 20 (69%), remission including 14 (48%) patients off immunosuppression. The proportion of patients with long-term remission was not related to the number of initial rituximab applications. No serious side effects were noted.

Conclusion: Rituximab is an effective treatment option in the short- and long-term control of treatment refractory SSNS. Further controlled studies are needed to address optimal patient selection, dose and safety of rituximab infusions.
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http://dx.doi.org/10.1093/ndt/gfr548DOI Listing
May 2012

Sequential maintenance therapy with cyclosporin A and mycophenolate mofetil for sustained remission of childhood steroid-resistant nephrotic syndrome.

Nephrol Dial Transplant 2012 May 4;27(5):1970-8. Epub 2011 Oct 4.

Department of Paediatric Nephrology, Charité Children’s Hospital, Berlin, Germany.

Background: There is currently no established standard for maintenance therapy of steroid-resistant nephrotic syndrome (SRNS). We report the long-term clinical course, medication, pharmacokinetic data, and renal function of 23 children with primary, non-familial SRNS with focal segmental glomerulosclerosis (FSGS).

Methods: To achieve initial remission, patients were treated with high-dose intravenous (i. v.) methylprednisolone and oral cyclosporin A (CsA). Maintenance therapy included transient alternate day oral prednisolone, CsA and angiotensin-converting enzyme (ACE) inhibitors and/or angiotensin receptor blockers. In 18 patients, mycophenolate mofetil (MMF) (adjusted to achieve blood mycophenolic acid trough concentrations > 2 μg/mL) was sequentially added, and 16 patients were converted to MMF monotherapy.

Results: During a mean follow-up time of 7.0 years (1.7-16.5 years; cumulative observation time 161 patient-years), sustained remission could be achieved in all patients. Five of 23 patients (21%) experienced 10 relapses; all responded to relapse therapy. Maintenance therapy could be permanently discontinued in seven patients (30%). After conversion from CsA to MMF, renal function improved significantly; the eGFR at last follow-up was 137 (range 106-198) mL/min × 1.73 m(2). The mean number of anti-hypertensive drugs decreased from 1.86 per patient after initial remission to 0.57 on MMF monotherapy (P < 0.002).

Conclusions: The data of this uncontrolled retrospective study indicate that in children with SRNS/FSGS achieving initial remission, a sequential steroid-free therapy consisting of a combination of CsA and MMF followed by MMF alone (with the addition of ACE inhibitors and angiotensin receptor blockers), can provide sustained long-term remission, preservation of renal function and better control of blood pressure.
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http://dx.doi.org/10.1093/ndt/gfr572DOI Listing
May 2012

A hospital-based intermittent nocturnal hemodialysis program for children and adolescents.

J Pediatr 2011 Jan 9;158(1):95-9, 99.e1. Epub 2010 Aug 9.

Charité, Department of Pediatric Nephrology, Berlin, Germany.

Objective: To establish a hospital-based nocturnal hemodialysis (NHD) program for children and adolescents.

Study Design: Sixteen patients (age, 0.5 to 17 years) were prospectively included. Uremia-associated measures as well as amount and dosage of medication were enumerated. Quality of life also was evaluated. Results were compared with data of the same patients on conventional hemodialysis and with matched control subjects (conventional HD).

Results: NHD was well tolerated. Median Kt/V values increased. Predialytic mean arterial pressure, urea, phosphate, and parathyroid hormone levels decreased. There was an increase in protein catabolic rate. Dietary and fluid restrictions could be lifted. Amount and dosage of phosphate and potassium binders and antihypertensive medication could be reduced. Quality of life improved and days of absence from school decreased in all patients.

Conclusions: In addition to a better control of uremia-associated measures, NHD allows free dietary and fluid intake and improves patient well-being. Given the continuing shortage of donor organs for kidney transplantation and the high morbidity and mortality on conventional HD, intensified dialysis regimens are a much-needed therapeutic option.
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http://dx.doi.org/10.1016/j.jpeds.2010.06.036DOI Listing
January 2011