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Akarkach A, Burgmaier K, Sander A, Hooman N, Sever L, Cano F, Zambrano P, Bilge I, Flynn JT, Yavascan O, Vallés PG, Munarriz RL, Patel HP, Serdaroglu E, Koch VH, Suarez ADC, Galanti M, Celedon CG, Rébori A, Kari JA, Wong CJ, Elenberg E, Rojas LF, Warady BA, Liebau MC, Schaefer F. Maintenance Peritoneal Dialysis in Children With Autosomal Recessive Polycystic Kidney Disease: A Comparative Cohort Study of the International Pediatric Peritoneal Dialysis Network Registry. Am J Kidney Dis 2020; 75:460-464. [PMID: 31983502 DOI: 10.1053/j.ajkd.2019.10.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Accepted: 10/06/2019] [Indexed: 01/18/2023]
Affiliation(s)
- Abdelaziz Akarkach
- University of Cologne, Faculty of Medicine and University Hospital Cologne, Department of Pediatrics, Cologne, Germany
| | - Kathrin Burgmaier
- University of Cologne, Faculty of Medicine and University Hospital Cologne, Department of Pediatrics, Cologne, Germany
| | - Anja Sander
- Institute of Medical Biometry and Informatics, University of Heidelberg, Heidelberg, Germany
| | - Nakysa Hooman
- Ali-Asghar Clinical Research Development Center, Iran University of Medical Sciences, Tehran, Iran
| | - Lale Sever
- Pediatric Nephrology, Cerrahpaşa Faculty of Medicine, Istanbul University-Cerrahpaşa, Istanbul, Turkey
| | - Francisco Cano
- Division of Pediatrics, Luis Calvo Mackenna Children's Hospital, Faculty of Medicine, University of Chile, Santiago, Chile
| | | | - Ilmay Bilge
- Department of Pediatric Nephrology, Istanbul University Medical Faculty, Istanbul, Turkey
| | - Joseph T Flynn
- Department of Pediatrics, University of Washington School of Medicine, Seattle, WA; Division of Nephrology, Seattle Children's Hospital, Seattle, WA
| | - Onder Yavascan
- Department of Pediatric Nephrology, Tepecik Teaching and Research Hospital, Izmir, Turkey
| | | | | | - Hiren P Patel
- Department of Pediatrics, Ohio State University College of Medicine and Nationwide Children's Hospital, Columbus, OH
| | - Erkin Serdaroglu
- Department of Pediatric Nephrology, Dr. Behçet Uz Children's Hospital, Izmir, Turkey
| | - Vera H Koch
- Pediatric Nephrology Unit, Instituto da Criança Hospital das Clinicas, University of Sao Paulo Medical School, Sao Paulo, Brazil
| | - Angela Del Carmen Suarez
- Department of Nephrology, Hospital de Niños Sor María Ludovica La Plata, Buenos Aires, Argentina
| | - Monica Galanti
- Pediatric Nephrology, Roberto del Río Hospital, Santiago, Chile
| | | | - Anabella Rébori
- Pediatric Dialysis Unit, Senniad, Hospital Evangelico, Montevideo, Uruguay
| | - Jameela A Kari
- Pediatric Nephrology Center of Excellence and Pediatric Department, Faculty of Medicine, King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia
| | - Cynthia J Wong
- Division of Nephrology, Department of Pediatrics, Stanford University School of Medicine, Palo Alto, CA
| | | | - Luisa F Rojas
- Baxter Servicio al Cliente Colombia, Medellin-Antioquia, Colombia
| | - Bradley A Warady
- Division of Nephrology, Children's Mercy Kansas City, University of Missouri-Kansas City School of Medicine, Kansas City, MO
| | - Max C Liebau
- University of Cologne, Faculty of Medicine and University Hospital Cologne, Department of Pediatrics, Cologne, Germany; Center for Molecular Medicine Cologne, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.
| | - Franz Schaefer
- Division of Pediatric Nephrology, Center for Pediatrics and Adolescent Medicine, University Hospital of Heidelberg, Heidelberg, Germany.
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Kampf LL, Schneider R, Gerstner L, Thünauer R, Chen M, Helmstädter M, Amar A, Onuchic-Whitford AC, Loza Munarriz R, Berdeli A, Müller D, Schrezenmeier E, Budde K, Mane S, Laricchia KM, Rehm HL, MacArthur DG, Lifton RP, Walz G, Römer W, Bergmann C, Hildebrandt F, Hermle T. TBC1D8B Mutations Implicate RAB11-Dependent Vesicular Trafficking in the Pathogenesis of Nephrotic Syndrome. J Am Soc Nephrol 2019; 30:2338-2353. [PMID: 31732614 DOI: 10.1681/asn.2019040414] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 08/07/2019] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Mutations in about 50 genes have been identified as monogenic causes of nephrotic syndrome, a frequent cause of CKD. These genes delineated the pathogenetic pathways and rendered significant insight into podocyte biology. METHODS We used whole-exome sequencing to identify novel monogenic causes of steroid-resistant nephrotic syndrome (SRNS). We analyzed the functional significance of an SRNS-associated gene in vitro and in podocyte-like Drosophila nephrocytes. RESULTS We identified hemizygous missense mutations in the gene TBC1D8B in five families with nephrotic syndrome. Coimmunoprecipitation assays indicated interactions between TBC1D8B and active forms of RAB11. Silencing TBC1D8B in HEK293T cells increased basal autophagy and exocytosis, two cellular functions that are independently regulated by RAB11. This suggests that TBC1D8B plays a regulatory role by inhibiting endogenous RAB11. Coimmunoprecipitation assays showed TBC1D8B also interacts with the slit diaphragm protein nephrin, and colocalizes with it in immortalized cell lines. Overexpressed murine Tbc1d8b with patient-derived mutations had lower affinity for endogenous RAB11 and nephrin compared with wild-type Tbc1d8b protein. Knockdown of Tbc1d8b in Drosophila impaired function of the podocyte-like nephrocytes, and caused mistrafficking of Sns, the Drosophila ortholog of nephrin. Expression of Rab11 RNAi in nephrocytes entailed defective delivery of slit diaphragm protein to the membrane, whereas RAB11 overexpression revealed a partial phenotypic overlap to Tbc1d8b loss of function. CONCLUSIONS Novel mutations in TBC1D8B are monogenic causes of SRNS. This gene inhibits RAB11. Our findings suggest that RAB11-dependent vesicular nephrin trafficking plays a role in the pathogenesis of nephrotic syndrome.
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Affiliation(s)
- Lina L Kampf
- Renal Division, Department of Medicine, Faculty of Medicine and Medical Center, University of Freiburg, Freiburg, Germany
| | - Ronen Schneider
- Division of Nephrology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Lea Gerstner
- Renal Division, Department of Medicine, Faculty of Medicine and Medical Center, University of Freiburg, Freiburg, Germany
| | - Roland Thünauer
- Signalling Research Centres BIOSS and CIBSS and Faculty of Biology, University of Freiburg, Freiburg, Germany.,Advanced Light and Fluorescence Microscopy Facility, Centre for Structural Systems Biology (CSSB) and University of Hamburg, Hamburg, Germany
| | - Mengmeng Chen
- Renal Division, Department of Medicine, Faculty of Medicine and Medical Center, University of Freiburg, Freiburg, Germany
| | - Martin Helmstädter
- Renal Division, Department of Medicine, Faculty of Medicine and Medical Center, University of Freiburg, Freiburg, Germany
| | - Ali Amar
- Division of Nephrology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Ana C Onuchic-Whitford
- Division of Nephrology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts.,Renal Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | | | - Afig Berdeli
- Department of Pediatrics, Molecular Medicine Laboratory, Ege University, Izmir, Turkey
| | - Dominik Müller
- Department of Pediatric Nephrology, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Eva Schrezenmeier
- Department of Nephrology and Medical Intensive Care, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Klemens Budde
- Department of Nephrology and Medical Intensive Care, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Shrikant Mane
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut
| | - Kristen M Laricchia
- Broad Center for Mendelian Genomics, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge
| | - Heidi L Rehm
- Broad Center for Mendelian Genomics, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge
| | - Daniel G MacArthur
- Broad Center for Mendelian Genomics, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge
| | - Richard P Lifton
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut.,Laboratory of Human Genetics and Genomics, The Rockefeller University, New York, New York
| | - Gerd Walz
- Renal Division, Department of Medicine, Faculty of Medicine and Medical Center, University of Freiburg, Freiburg, Germany
| | - Winfried Römer
- Signalling Research Centres BIOSS and CIBSS and Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Carsten Bergmann
- Center for Human Genetics, Mainz, Germany.,Center for Human Genetics, Bioscientia, Ingelheim, Germany; and.,Department of Medicine, University Hospital Freiburg, Freiburg, Germany
| | - Friedhelm Hildebrandt
- Division of Nephrology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts;
| | - Tobias Hermle
- Renal Division, Department of Medicine, Faculty of Medicine and Medical Center, University of Freiburg, Freiburg, Germany;
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Warejko JK, Tan W, Daga A, Schapiro D, Lawson JA, Shril S, Lovric S, Ashraf S, Rao J, Hermle T, Jobst-Schwan T, Widmeier E, Majmundar AJ, Schneider R, Gee HY, Schmidt JM, Vivante A, van der Ven AT, Ityel H, Chen J, Sadowski CE, Kohl S, Pabst WL, Nakayama M, Somers MJG, Rodig NM, Daouk G, Baum M, Stein DR, Ferguson MA, Traum AZ, Soliman NA, Kari JA, El Desoky S, Fathy H, Zenker M, Bakkaloglu SA, Müller D, Noyan A, Ozaltin F, Cadnapaphornchai MA, Hashmi S, Hopcian J, Kopp JB, Benador N, Bockenhauer D, Bogdanovic R, Stajić N, Chernin G, Ettenger R, Fehrenbach H, Kemper M, Munarriz RL, Podracka L, Büscher R, Serdaroglu E, Tasic V, Mane S, Lifton RP, Braun DA, Hildebrandt F. Whole Exome Sequencing of Patients with Steroid-Resistant Nephrotic Syndrome. Clin J Am Soc Nephrol 2018; 13:53-62. [PMID: 29127259 PMCID: PMC5753307 DOI: 10.2215/cjn.04120417] [Citation(s) in RCA: 139] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 09/12/2017] [Indexed: 12/30/2022]
Abstract
BACKGROUND AND OBJECTIVES Steroid-resistant nephrotic syndrome overwhelmingly progresses to ESRD. More than 30 monogenic genes have been identified to cause steroid-resistant nephrotic syndrome. We previously detected causative mutations using targeted panel sequencing in 30% of patients with steroid-resistant nephrotic syndrome. Panel sequencing has a number of limitations when compared with whole exome sequencing. We employed whole exome sequencing to detect monogenic causes of steroid-resistant nephrotic syndrome in an international cohort of 300 families. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Three hundred thirty-five individuals with steroid-resistant nephrotic syndrome from 300 families were recruited from April of 1998 to June of 2016. Age of onset was restricted to <25 years of age. Exome data were evaluated for 33 known monogenic steroid-resistant nephrotic syndrome genes. RESULTS In 74 of 300 families (25%), we identified a causative mutation in one of 20 genes known to cause steroid-resistant nephrotic syndrome. In 11 families (3.7%), we detected a mutation in a gene that causes a phenocopy of steroid-resistant nephrotic syndrome. This is consistent with our previously published identification of mutations using a panel approach. We detected a causative mutation in a known steroid-resistant nephrotic syndrome gene in 38% of consanguineous families and in 13% of nonconsanguineous families, and 48% of children with congenital nephrotic syndrome. A total of 68 different mutations were detected in 20 of 33 steroid-resistant nephrotic syndrome genes. Fifteen of these mutations were novel. NPHS1, PLCE1, NPHS2, and SMARCAL1 were the most common genes in which we detected a mutation. In another 28% of families, we detected mutations in one or more candidate genes for steroid-resistant nephrotic syndrome. CONCLUSIONS Whole exome sequencing is a sensitive approach toward diagnosis of monogenic causes of steroid-resistant nephrotic syndrome. A molecular genetic diagnosis of steroid-resistant nephrotic syndrome may have important consequences for the management of treatment and kidney transplantation in steroid-resistant nephrotic syndrome.
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Affiliation(s)
- Jillian K Warejko
- Due to the number of contributing authors, the affiliations are provided in the Supplemental Material
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Borzych-Duzalka D, Bilginer Y, Ha IS, Bak M, Rees L, Cano F, Munarriz RL, Chua A, Pesle S, Emre S, Urzykowska A, Quiroz L, Ruscasso JD, White C, Pape L, Ramela V, Printza N, Vogel A, Kuzmanovska D, Simkova E, Müller-Wiefel DE, Sander A, Warady BA, Schaefer F. Management of anemia in children receiving chronic peritoneal dialysis. J Am Soc Nephrol 2013; 24:665-76. [PMID: 23471197 DOI: 10.1681/asn.2012050433] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Little information exists regarding the efficacy, modifiers, and outcomes of anemia management in children with CKD or ESRD. We assessed practices, effectors, and outcomes of anemia management in 1394 pediatric patients undergoing peritoneal dialysis (PD) who were prospectively followed in 30 countries. We noted that 25% of patients had hemoglobin levels below target (<10 g/dl or <9.5 g/dl in children older or younger than 2 years, respectively), with significant regional variation; levels were highest in North America and Europe and lowest in Asia and Turkey. Low hemoglobin levels were associated with low urine output, low serum albumin, high parathyroid hormone, high ferritin, and the use of bioincompatible PD fluid. Erythropoiesis-stimulating agents (ESAs) were prescribed to 92% of patients, and neither the type of ESA nor the dosing interval appeared to affect efficacy. The weekly ESA dose inversely correlated with age when scaled to weight but did not correlate with age when normalized to body surface area. ESA sensitivity was positively associated with residual diuresis and serum albumin and inversely associated with serum parathyroid hormone and ferritin. The prevalence of hypertension and left ventricular hypertrophy increased with the degree of anemia. Patient survival was positively associated with achieved hemoglobin and serum albumin and was inversely associated with ESA dose. In conclusion, control of anemia in children receiving long-term PD varies by region. ESA requirements are independent of age when dose is scaled to body surface area, and ESA resistance is associated with inflammation, fluid retention, and hyperparathyroidism. Anemia and high ESA dose requirements independently predict mortality.
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Affiliation(s)
- Dagmara Borzych-Duzalka
- Pediatric Nephrology Division, Center for Pediatrics and Adolescent Medicine, Heidelberg, Germany
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Schaefer F, Borzych-Duzalka D, Azocar M, Munarriz RL, Sever L, Aksu N, Barbosa LS, Galan YS, Xu H, Coccia PA, Szabo A, Wong W, Salim R, Vidal E, Pottoore S, Warady BA. Impact of global economic disparities on practices and outcomes of chronic peritoneal dialysis in children: insights from the International Pediatric Peritoneal Dialysis Network Registry. Perit Dial Int 2012; 32:399-409. [PMID: 22859840 PMCID: PMC3524840 DOI: 10.3747/pdi.2012.00126] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Accepted: 06/19/2012] [Indexed: 11/15/2022] Open
Abstract
UNLABELLED BACKGROUND, OBJECTIVES, AND METHODS: The number of patients on chronic peritoneal dialysis (CPD) is increasing rapidly on a global scale. We analyzed the International Pediatric Peritoneal Dialysis Network (IPPN) registry, a global database active in 33 countries spanning a wide range in gross national income (GNI), to identify the impact of economic conditions on CPD practices and outcomes in children and adolescents. RESULTS We observed close associations of GNI with the fraction of very young patients on dialysis, the presence and number of comorbidities, the prevalence of patients with unexplained causes of end-stage kidney disease, and the rate of culture-negative peritonitis. The prevalence of automated PD increased with GNI, but was 46% even in the lowest GNI stratum. The GNI stratum also affected the use of biocompatible peritoneal dialysis fluids, enteral tube feeding, calcium-free phosphate binders, active vitamin D analogs, and erythropoiesis-stimulating agents (ESAs). Patient mortality was strongly affected by GNI (hazard ratio per $10 000: 3.3; 95% confidence interval: 2.0 to 5.5) independently of young patient age and the number of comorbidities present. Patients from low-income countries tended to die more often from infections unrelated to CPD (5 of 9 vs 15 of 61, p = 0.1). The GNI was also a strong independent predictor of standardized height (p < 0.0001), adding to the impact of congenital renal disease, anuria, age at PD start, and dialysis vintage. Patients from the lower economic strata (GNI < $18 000) had higher serum parathyroid hormone (PTH) and lower serum calcium, and achieved lower hemoglobin concentrations. No impact of GNI was observed with regard to CPD technique survival or peritonitis incidence. CONCLUSIONS We conclude that CPD is practiced successfully, albeit with major regional variation related to economic differences, in children around the globe. The variations encompass the acceptance of very young patients and those with associated comorbidities to chronic dialysis programs, the use of automated PD and expensive drugs, and the diagnostic management of peritonitis. These variations in practice related to economic difference do not appear to affect PD technique survival; however, economic conditions seem to affect mortality on dialysis and standardized height, a marker of global child morbidity.
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Affiliation(s)
- Franz Schaefer
- Pediatric Nephrology Division, Center for Pediatrics and Adolescent Medicine, Im Neuenheimer Feld 430, Heidelberg, Germany.
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