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Anderson CE, Tuokkola J, Qizalbash L, Harmer M, Nelms CL, Stabouli S, Toole B, Polderman N, Desloovere A, Renken-Terhaerdt J, Vega MRW, Snauwaert E, Walle JV, Haffner D, Paglialonga F, Shroff R, Shaw V, Greenbaum LA, Warady BA. Assessment and management of vitamin status in children with CKD stages 2-5, on dialysis and post-transplantation: clinical practice points from the Pediatric Renal Nutrition Taskforce. Pediatr Nephrol 2024:10.1007/s00467-024-06303-x. [PMID: 38570350 DOI: 10.1007/s00467-024-06303-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 01/10/2024] [Accepted: 01/10/2024] [Indexed: 04/05/2024]
Abstract
Children with chronic kidney disease (CKD) are at risk for vitamin deficiency or excess. Vitamin status can be affected by diet, supplements, kidney function, medications, and dialysis. Little is known about vitamin requirements in CKD, leading to practice variation.The Pediatric Renal Nutrition Taskforce (PRNT), an international team of pediatric kidney dietitians and pediatric nephrologists, was established to develop evidence-based clinical practice points (CPPs) to address challenges and to serve as a resource for nutritional care. Questions were formulated using PICO (Patient, Intervention, Comparator, Outcomes), and literature searches undertaken to explore clinical practice from assessment to management of vitamin status in children with CKD stages 2-5, on dialysis and post-transplantation (CKD2-5D&T). The CPPs were developed and finalized using a Delphi consensus approach. We present six CPPs for vitamin management for children with CKD2-5D&T. We address assessment, intervention, and monitoring. We recommend avoiding supplementation of vitamin A and suggest water-soluble vitamin supplementation for those on dialysis. In the absence of evidence, a consistent structured approach to vitamin management that considers assessment and monitoring from dietary, physical, and biochemical viewpoints is needed. Careful consideration of the impact of accumulation, losses, comorbidities, and medications needs to be explored for the individual child and vitamin before supplementation can be considered. When supplementing, care needs to be taken not to over-prescribe. Research recommendations are suggested.
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Affiliation(s)
- Caroline E Anderson
- University Hospital Southampton NHS Foundation Trust, Southampton, UK.
- Human Development & Health, Faculty of Medicine, University of Southampton, Southampton, UK.
- University of Winchester, Winchester, UK.
| | - Jetta Tuokkola
- Clinical Nutrition Unit, Internal Medicine and Rehabilitation, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
- Institute of Public Health and Clinical Nutrition, University of Eastern Finland, Kuopio, Finland
- Department of Medicine, Endocrinology and Clinical Nutrition, Kuopio University Hospital, Kuopio, Finland
| | | | - Matthew Harmer
- University Hospital Southampton NHS Foundation Trust, Southampton, UK
| | | | - Stella Stabouli
- 1st Department of Pediatrics, Aristotle University, Hippokratio Hospital, Thessaloniki, Greece
| | - Barry Toole
- Great Northern Children's Hospital, Newcastle Upon Tyne, UK
| | | | | | - Jose Renken-Terhaerdt
- Wilhemina Children's Hospital, University Medical Center Utrecht, Utrecht, The Netherlands
| | | | | | | | - Dieter Haffner
- Hannover Medical School, Children's Hospital, Hannover, Germany
| | - Fabio Paglialonga
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Rukshana Shroff
- University College London Great Ormond Street Hospital Institute of Child Health, London, UK
| | - Vanessa Shaw
- University College London Great Ormond Street Hospital Institute of Child Health, London, UK
| | - Larry A Greenbaum
- Emory University, Atlanta, GA, USA
- Children's Healthcare of Atlanta, Atlanta, GA, USA
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Ragate DC, Memon SS, Karlekar M, Lila AR, Sarathi V, Jamale T, Thakare S, Patil VA, Shah NS, Bandgar TR. Inherited Fanconi renotubular syndromes: unveiling the intricacies of hypophosphatemic rickets/osteomalacia. J Bone Miner Metab 2024; 42:155-165. [PMID: 38310177 DOI: 10.1007/s00774-023-01490-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 11/16/2023] [Indexed: 02/05/2024]
Abstract
INTRODUCTION Fanconi renotubular syndromes (FRTS) are a rare group of inherited phosphaturic disorders with limited Indian as well as global data on this condition. Here, we describe the experience of a single Endocrinology center from Western India on FRTS. MATERIALS AND METHODS Comprehensive clinical, biochemical, radiological, management, and genetic details of FRTS patients managed between 2010 and 2023 were collected and analyzed. RESULTS FRTS probands had mutations (eight novel) in six genes [CLCN5 (n = 4), SLC2A2 (n = 2), GATM, EHHADH, HNF4A, and OCRL (1 each)]. Among 15 FRTS patients (11 families), rickets/osteomalacia was the most common (n = 14) presentation with wide inter- and intra-familial phenotypic variability. Delayed diagnosis (median: 8.8 years), initial misdiagnosis (8/11 probands), and syndrome-specific discriminatory features (8/11 probands) were commonly seen. Hypophosphatemia, elevated alkaline phosphatase, normal parathyroid hormone (median: 36 pg/ml), high-normal/elevated 1,25(OH)2D (median: 152 pg/ml), hypercalciuria (median spot urinary calcium to creatinine ratio: 0.32), and variable proximal tubular dysfunction(s) were observed. Elevated C-terminal fibroblast growth factor 23 in two probands was misleading, till the genetic diagnosis was reached. Novel observations in our FRTS cohort were preserved renal function (till sixth decade) and enthesopathy in FRTS1 and FRTS3 families, respectively. CONCLUSION Our findings underscore frequent under- and misdiagnosis of FRTS; hence, a high index of suspicion for FRTS in phosphopenic rickets/osteomalacia, with early consideration of genetic testing is essential to ensure timely diagnosis of FRTS. The novel variants and phenotypic manifestations described here expand the disease spectrum of FRTS.
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Affiliation(s)
- Divya C Ragate
- Department of Endocrinology OPD, Seth G.S. Medical College and KEM Hospital, Parel, Mumbai, Maharashtra, 4000012, India
| | - Saba Samad Memon
- Department of Endocrinology OPD, Seth G.S. Medical College and KEM Hospital, Parel, Mumbai, Maharashtra, 4000012, India.
| | - Manjiri Karlekar
- Department of Endocrinology OPD, Seth G.S. Medical College and KEM Hospital, Parel, Mumbai, Maharashtra, 4000012, India
| | - Anurag Ranjan Lila
- Department of Endocrinology OPD, Seth G.S. Medical College and KEM Hospital, Parel, Mumbai, Maharashtra, 4000012, India
| | - Vijaya Sarathi
- Department of Endocrinology, Vydehi Institute of Medical Sciences and Research Centre, Bangalore, Karnataka, India
| | - Tukaram Jamale
- Department of Nephrology, Seth G.S. Medical College and KEM Hospital, Mumbai, Maharashtra, India
| | - Sayali Thakare
- Department of Nephrology, Seth G.S. Medical College and KEM Hospital, Mumbai, Maharashtra, India
| | - Virendra A Patil
- Department of Endocrinology OPD, Seth G.S. Medical College and KEM Hospital, Parel, Mumbai, Maharashtra, 4000012, India
| | - Nalini S Shah
- Department of Endocrinology OPD, Seth G.S. Medical College and KEM Hospital, Parel, Mumbai, Maharashtra, 4000012, India
| | - Tushar R Bandgar
- Department of Endocrinology OPD, Seth G.S. Medical College and KEM Hospital, Parel, Mumbai, Maharashtra, 4000012, India
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Arnett JJ, Li A, Yassin SH, Miller R, Taylor L, Carter CE, Shayan-Tabrizi K, Borooah S. Dent disease presenting with nyctalopia and electroretinographic correlates of vitamin A deficiency. Am J Ophthalmol Case Rep 2022; 29:101781. [PMID: 36578800 PMCID: PMC9791604 DOI: 10.1016/j.ajoc.2022.101781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Revised: 11/24/2022] [Accepted: 12/12/2022] [Indexed: 12/23/2022] Open
Abstract
Purpose To report a unique case of Dent Disease presenting with nyctalopia associated with vitamin A deficiency and abnormal electroretinogram findings without prior systemic symptomatology. Observations A 16-year-old male presented with a several month history of nyctalopia and peripheral vision deficits. Central visual acuity, anterior and posterior segment examinations, and macular optical coherence tomography were unremarkable. Electroretinogram (ERG) testing revealed a rod-cone dystrophic pattern, with further workup demonstrating serum vitamin A deficiency (VAD). Laboratory evaluation revealed renal dysfunction and proteinuria with a significantly elevated urinary retinol-binding protein (RBP). Kidney biopsy showed glomerular and tubular disease.Genetic screening for inherited renal disease was performed identifying a hemizygous pathogenic variant c.2152C>T (p.Arg718*) in the Chloride Voltage-Gated Channel 5 (CLCN5) gene, confirming the diagnosis of X-linked Dent Disease. Following vitamin A supplementation, our patient reported resolution of nyctalopia and reversal of abnormal ERG findings were demonstrated. Conclusions and Importance To our knowledge, this is the first case in the literature describing Dent disease solely presenting with ophthalmic symptoms of nyctalopia and abnormal electroretinogram findings that later reversed with vitamin A repletion. This case stresses the importance for clinicians to consider renal tubular disorders in the differential for VAD.
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Affiliation(s)
- Justin J. Arnett
- Viterbi Department of Ophthalmology, Shiley Eye Institute, University of California, San Diego, 9415 Campus Point Drive, La Jolla, CA, 92093, USA
| | - Alexa Li
- Viterbi Department of Ophthalmology, Shiley Eye Institute, University of California, San Diego, 9415 Campus Point Drive, La Jolla, CA, 92093, USA
| | - Shaden H. Yassin
- Viterbi Department of Ophthalmology, Shiley Eye Institute, University of California, San Diego, 9415 Campus Point Drive, La Jolla, CA, 92093, USA
| | - Robin Miller
- Division of Pediatric Nephrology, Rady Children's Hospital San Diego, 3020 Children's Way, San Diego, CA, 92123, USA,Department of Pediatrics, University of California, San Diego, 8910 Villa La Jolla Drive, La Jolla, CA, 92037, USA
| | - Lori Taylor
- Coast Pediatrics, Del Mar, 12845 Pointe Del Mar, Suite 200, Del Mar, CA, 92014, USA
| | - Caitlin E. Carter
- Division of Pediatric Nephrology, Rady Children's Hospital San Diego, 3020 Children's Way, San Diego, CA, 92123, USA,Department of Pediatrics, University of California, San Diego, 8910 Villa La Jolla Drive, La Jolla, CA, 92037, USA
| | - Katayoon Shayan-Tabrizi
- Department of Pediatric Pathology, Rady Children's Hospital San Diego, 3020 Children's Way, San Diego, CA, 92123, USA
| | - Shyamanga Borooah
- Viterbi Department of Ophthalmology, Shiley Eye Institute, University of California, San Diego, 9415 Campus Point Drive, La Jolla, CA, 92093, USA,Corresponding author. Shiley Eye Institute, University of California San Diego, 9415 Campus Point Drive, La Jolla, CA, 92093, USA.
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Gianesello L, Del Prete D, Anglani F, Calò LA. Genetics and phenotypic heterogeneity of Dent disease: the dark side of the moon. Hum Genet 2020; 140:401-421. [PMID: 32860533 PMCID: PMC7889681 DOI: 10.1007/s00439-020-02219-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 08/20/2020] [Indexed: 12/18/2022]
Abstract
Dent disease is a rare genetic proximal tubulopathy which is under-recognized. Its phenotypic heterogeneity has led to several different classifications of the same disorder, but it is now widely accepted that the triad of symptoms low-molecular-weight proteinuria, hypercalciuria and nephrocalcinosis/nephrolithiasis are pathognomonic of Dent disease. Although mutations on the CLCN5 and OCRL genes are known to cause Dent disease, no such mutations are found in about 25–35% of cases, making diagnosis more challenging. This review outlines current knowledge regarding Dent disease from another perspective. Starting from the history of Dent disease, and reviewing the clinical details of patients with and without a genetic characterization, we discuss the phenotypic and genetic heterogeneity that typifies this disease. We focus particularly on all those confounding clinical signs and symptoms that can lead to a misdiagnosis. We also try to shed light on a concealed aspect of Dent disease. Although it is a proximal tubulopathy, its misdiagnosis may lead to patients undergoing kidney biopsy. In fact, some individuals with Dent disease have high-grade proteinuria, with or without hematuria, as in the clinical setting of glomerulopathy, or chronic kidney disease of uncertain origin. Although glomerular damage is frequently documented in Dent disease patients’ biopsies, there is currently no reliable evidence of renal biopsy being of either diagnostic or prognostic value. We review published histopathology reports of tubular and glomerular damage in these patients, and discuss current knowledge regarding the role of CLCN5 and OCRL genes in glomerular function.
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Affiliation(s)
- Lisa Gianesello
- Nephrology, Dialysis and Transplantation Unit, Kidney Histomorphology and Molecular Biology Laboratory, Department of Medicine-DIMED, University of Padua, Via Giustiniani n° 2, 35128, Padua, Italy
| | - Dorella Del Prete
- Nephrology, Dialysis and Transplantation Unit, Kidney Histomorphology and Molecular Biology Laboratory, Department of Medicine-DIMED, University of Padua, Via Giustiniani n° 2, 35128, Padua, Italy
| | - Franca Anglani
- Nephrology, Dialysis and Transplantation Unit, Kidney Histomorphology and Molecular Biology Laboratory, Department of Medicine-DIMED, University of Padua, Via Giustiniani n° 2, 35128, Padua, Italy.
| | - Lorenzo A Calò
- Nephrology, Dialysis and Transplantation Unit, Kidney Histomorphology and Molecular Biology Laboratory, Department of Medicine-DIMED, University of Padua, Via Giustiniani n° 2, 35128, Padua, Italy
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Gianesello L, Del Prete D, Ceol M, Priante G, Calò LA, Anglani F. From protein uptake to Dent disease: An overview of the CLCN5 gene. Gene 2020; 747:144662. [PMID: 32289351 DOI: 10.1016/j.gene.2020.144662] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 04/07/2020] [Indexed: 12/12/2022]
Abstract
Proteinuria is a well-known risk factor, not only for renal disorders, but also for several other problems such as cardiovascular diseases and overall mortality. In the kidney, the chloride channel Cl-/H+ exchanger ClC-5 encoded by the CLCN5 gene is actively involved in preventing protein loss. This action becomes evident in patients suffering from the rare proximal tubulopathy Dent disease because they carry a defective ClC-5 due to CLCN5 mutations. In fact, proteinuria is the distinctive clinical sign of Dent disease, and mainly involves the loss of low-molecular-weight proteins. The identification of CLCN5 disease-causing mutations has greatly improved our understanding of ClC-5 function and of the ClC-5-related physiological processes in the kidney. This review outlines current knowledge regarding the CLCN5 gene and its protein product, providing an update on ClC-5 function in tubular and glomerular cells, and focusing on its relationship with proteinuria and Dent disease.
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Affiliation(s)
- Lisa Gianesello
- Kidney Histomorphology and Molecular Biology Laboratory, Clinical Nephrology Unit, Department of Medicine - DIMED, University of Padua, Padua, Italy.
| | - Dorella Del Prete
- Kidney Histomorphology and Molecular Biology Laboratory, Clinical Nephrology Unit, Department of Medicine - DIMED, University of Padua, Padua, Italy.
| | - Monica Ceol
- Kidney Histomorphology and Molecular Biology Laboratory, Clinical Nephrology Unit, Department of Medicine - DIMED, University of Padua, Padua, Italy.
| | - Giovanna Priante
- Kidney Histomorphology and Molecular Biology Laboratory, Clinical Nephrology Unit, Department of Medicine - DIMED, University of Padua, Padua, Italy.
| | - Lorenzo Arcangelo Calò
- Kidney Histomorphology and Molecular Biology Laboratory, Clinical Nephrology Unit, Department of Medicine - DIMED, University of Padua, Padua, Italy.
| | - Franca Anglani
- Kidney Histomorphology and Molecular Biology Laboratory, Clinical Nephrology Unit, Department of Medicine - DIMED, University of Padua, Padua, Italy.
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van der Wijst J, Belge H, Bindels RJM, Devuyst O. Learning Physiology From Inherited Kidney Disorders. Physiol Rev 2019; 99:1575-1653. [PMID: 31215303 DOI: 10.1152/physrev.00008.2018] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The identification of genes causing inherited kidney diseases yielded crucial insights in the molecular basis of disease and improved our understanding of physiological processes that operate in the kidney. Monogenic kidney disorders are caused by mutations in genes coding for a large variety of proteins including receptors, channels and transporters, enzymes, transcription factors, and structural components, operating in specialized cell types that perform highly regulated homeostatic functions. Common variants in some of these genes are also associated with complex traits, as evidenced by genome-wide association studies in the general population. In this review, we discuss how the molecular genetics of inherited disorders affecting different tubular segments of the nephron improved our understanding of various transport processes and of their involvement in homeostasis, while providing novel therapeutic targets. These include inherited disorders causing a dysfunction of the proximal tubule (renal Fanconi syndrome), with emphasis on epithelial differentiation and receptor-mediated endocytosis, or affecting the reabsorption of glucose, the handling of uric acid, and the reabsorption of sodium, calcium, and magnesium along the kidney tubule.
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Affiliation(s)
- Jenny van der Wijst
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
| | - Hendrica Belge
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
| | - René J M Bindels
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
| | - Olivier Devuyst
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
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van Berkel Y, Ludwig M, van Wijk JAE, Bökenkamp A. Proteinuria in Dent disease: a review of the literature. Pediatr Nephrol 2017; 32:1851-1859. [PMID: 27757584 PMCID: PMC5579149 DOI: 10.1007/s00467-016-3499-x] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 08/23/2016] [Accepted: 08/25/2016] [Indexed: 12/18/2022]
Abstract
BACKGROUND Dent disease is a rare X-linked recessive proximal tubulopathy caused by mutations in CLCN5 (Dent-1) or OCRL (Dent-2). As a rule, total protein excretion (TPE) is low in tubular proteinuria compared with glomerular disease. Several authors have reported nephrotic-range proteinuria (NP) and glomerulosclerosis in Dent disease. Therefore, we aimed to analyze protein excretion in patients with documented CLCN5 or OCRL mutations in a systematic literature review. DESIGN PubMed and Embase were searched for cases with documented CLCN5 or OCRL mutations and (semi-)quantitative data on protein excretion. The most reliable data (i.e., TPE > protein-creatinine ratio > Albustix) was used for NP classification. RESULTS Data were available on 148 patients from 47 reports: 126 had a CLCN5 and 22 an OCRLmutation. TPE was not significantly different between both forms (p = 0.11). Fifty-five of 126 (43.7 %) Dent-1 vs 13/22 (59.1 %) Dent-2 patients met the definition of NP (p = 0.25). Serum albumin was normal in all reported cases (24/148). Glomerulosclerosis was noted in 20/32 kidney biopsies and was strongly related to tubulointerstitial fibrosis, but not to kidney function or proteinuria. CONCLUSION More than half of the patients with both forms of Dent disease have NP, and the presence of low molecular weight proteinuria in a patient with NP in the absence of edema and hypoalbuminemia should prompt genetic testing. Even with normal renal function, glomerulosclerosis and tubulointerstitial fibrosis are present in Dent disease. The role of proteinuria in the course of the disease needs to be examined further in longitudinal studies.
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Affiliation(s)
- Youri van Berkel
- Department of Pediatric Nephrology, VU University Medical Center, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands
| | - Michael Ludwig
- Department of Clinical Chemistry and Clinical Pharmacology, University of Bonn, Bonn, Germany
| | - Joanna A E van Wijk
- Department of Pediatric Nephrology, VU University Medical Center, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands
| | - Arend Bökenkamp
- Department of Pediatric Nephrology, VU University Medical Center, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands.
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Abstract
OBJECTIVE To describe the clinical and genotypic features of Dent disease in children diagnosed at our center over a period of 10 years. DESIGN Case series. SETTING Pediatric Nephrology Clinic at a referral center in Northern India. METHODS The medical records of patients with Dent disease diagnosed and followed up at this hospital from June 2005 to April 2015 were reviewed. The diagnosis of Dent disease was based on presence of all three of the following: (i) low molecular weight proteinuria, (ii) hypercalciuria and (iii) one of the following: nephrolithiasis, hematuria, hypophosphatemia or renal insufficiency, with or without mutation in CLCN5 or OCRL1 genes. RESULTS The phenotype in 18 patients diagnosed with Dent disease during this period was characterized by early age at onset (median 1.8 y), and polyuria, polydipsia, salt craving, hypophosphatemic rickets and night blindness. Rickets was associated with severe deformities, fractures or loss of ambulation in six patients. Nephrocalcinosis was present in three patients, while none had nephrolithiasis. Generalized aminoaciduria was seen in 13 patients, two had glucosuria alone, and one had features of Fanconi syndrome. Over a median follow up of 2.7 years, one patient developed renal failure. Genetic testing (n=15) revealed 5 missense mutations and 3 nonsense mutations in CLCN5 in 13 patients. Five of these variations (p.Met504Lys, p.Trp58Cys, p.Leu729X, p.Glu527Gln and p.Gly57Arg) have not been reported outside the Indian subcontinent. CONCLUSION Our findings suggest a severe phenotype in a cohort of Indian patients with Dent disease.
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Tanumihardjo SA, Russell RM, Stephensen CB, Gannon BM, Craft NE, Haskell MJ, Lietz G, Schulze K, Raiten DJ. Biomarkers of Nutrition for Development (BOND)-Vitamin A Review. J Nutr 2016; 146:1816S-48S. [PMID: 27511929 PMCID: PMC4997277 DOI: 10.3945/jn.115.229708] [Citation(s) in RCA: 274] [Impact Index Per Article: 34.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Revised: 04/01/2016] [Accepted: 06/29/2016] [Indexed: 12/15/2022] Open
Abstract
The Biomarkers of Nutrition for Development (BOND) project is designed to provide evidence-informed advice to anyone with an interest in the role of nutrition in health. The BOND program provides information with regard to selection, use, and interpretation of biomarkers of nutrient exposure, status, function, and effect, which will be especially useful for readers who want to assess nutrient status. To accomplish this objective, expert panels are recruited to evaluate the literature and to draft comprehensive reports on the current state of the art with regard to specific nutrient biology and available biomarkers for assessing nutritional status at the individual and population levels. Phase I of the BOND project includes the evaluation of biomarkers for 6 nutrients: iodine, folate, zinc, iron, vitamin A, and vitamin B-12. This review of vitamin A is the current article in this series. Although the vitamin was discovered >100 y ago, vitamin A status assessment is not trivial. Serum retinol concentrations are under homeostatic control due in part to vitamin A's use in the body for growth and cellular differentiation and because of its toxic properties at high concentrations. Furthermore, serum retinol concentrations are depressed during infection and inflammation because retinol-binding protein (RBP) is a negative acute-phase reactant, which makes status assessment challenging. Thus, this review describes the clinical and functional indicators related to eye health and biochemical biomarkers of vitamin A status (i.e., serum retinol, RBP, breast-milk retinol, dose-response tests, isotope dilution methodology, and serum retinyl esters). These biomarkers are then related to liver vitamin A concentrations, which are usually considered the gold standard for vitamin A status. With regard to biomarkers, future research questions and gaps in our current understanding as well as limitations of the methods are described.
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Affiliation(s)
- Sherry A Tanumihardjo
- Interdepartmental Graduate Program in Nutritional Sciences, Department of Nutritional Sciences, University of Wisconsin-Madison, Madison, WI
| | | | | | - Bryan M Gannon
- Interdepartmental Graduate Program in Nutritional Sciences, Department of Nutritional Sciences, University of Wisconsin-Madison, Madison, WI
| | | | | | - Georg Lietz
- Newcastle University, Newcastle, United Kingdom
| | - Kerry Schulze
- Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD; and
| | - Daniel J Raiten
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD
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Renner AB, Dietrich-Ntoukas T, Jägle H. Recurrent episodes of night blindness in a patient with short bowel syndrome. Doc Ophthalmol 2015; 131:221-30. [PMID: 26507840 DOI: 10.1007/s10633-015-9516-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Accepted: 10/20/2015] [Indexed: 02/02/2023]
Abstract
PURPOSE To describe clinical characteristics in a patient with recurrent episodes of night blindness due to vitamin A deficiency caused by short bowel syndrome in Crohn disease. METHODS Retrospective analysis of best-corrected visual acuity (BCVA), kinetic perimetry, slit-lamp biomicroscopy, ophthalmoscopy, fundus photography, fundus autofluorescence (FAF), spectral domain optical coherence tomography (SD-OCT), dark adaptometry (DA) and electroretinography (ERG). Serum vitamin A level was measured. RESULTS A 44-year-old man with a 3-year history of night blindness suffered from a short bowel syndrome with chronic malabsorption due to ileocecal resection in Crohn disease. Both eyes had a BCVA of 0.9, Bitot's spots of the conjunctiva and no significant fundus abnormalities. SD-OCT showed no remarkable changes, whereas FAF was brighter than normal in the center of the fovea. DA showed normal cone and a lack of rod function. The dark-adapted 0.01 ERG was non-detectable, the dark-adapted 3.0 ERG severely diminished, but the light-adapted 3.0 and 30 Hz flicker ERGs were within normal limits. Serum vitamin A level was 0.11 µg/ml (normal 0.30-0.65 µg/ml). Treatment with intravenous vitamin A caused a rapid recovery of night vision and ERG. However, during the following 3 years, he had three further episodes of night blindness with loss of rod function. During each period, parenteral vitamin A substitution brought complete recovery of night vision and rod function. BCVA, fundus, FAF findings and SD-OCT remained unchanged during the course. CONCLUSIONS In patients with known chronic malabsorption serum vitamin A level should be regularly checked to avoid recurrent night blindness episodes. ERG might be more sensitive than serum vitamin A level and is recommended in case of night blindness but still normal vitamin A level.
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Affiliation(s)
- Agnes B Renner
- Klinik und Poliklinik für Augenheilkunde, Universitätsklinikum Regensburg, Franz-Josef-Strauss-Allee 11, 93053, Regensburg, Germany.
| | - Tina Dietrich-Ntoukas
- Klinik und Poliklinik für Augenheilkunde, Universitätsklinikum Regensburg, Franz-Josef-Strauss-Allee 11, 93053, Regensburg, Germany.,Klinik für Augenheilkunde, Charité Universitätsmedizin Berlin, Campus Virchow-Klinikum, Mittelallee 4, Augustenburgerplatz 1, 13353, Berlin, Germany
| | - Herbert Jägle
- Klinik und Poliklinik für Augenheilkunde, Universitätsklinikum Regensburg, Franz-Josef-Strauss-Allee 11, 93053, Regensburg, Germany
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Devuyst O, Luciani A. Chloride transporters and receptor-mediated endocytosis in the renal proximal tubule. J Physiol 2015; 593:4151-64. [PMID: 25820368 DOI: 10.1113/jp270087] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 03/16/2015] [Indexed: 01/09/2023] Open
Abstract
KEY POINTS The reabsorptive activity of renal proximal tubule cells is mediated by receptor-mediated endocytosis and polarized transport systems that reflect final cell differentiation. Loss-of-function mutations of the endosomal chloride-proton exchanger ClC-5 (Dent's disease) cause a major trafficking defect in proximal tubule cells, associated with lysosomal dysfunction, oxidative stress and dedifferentiation/proliferation. A similar but milder defect is associated with mutations in CFTR (cystic fibrosis transmembrane conductance regulator). Vesicular chloride transport appears to be important for the integrity of the endolysosomal pathway in epithelial cells. ABSTRACT The epithelial cells lining the proximal tubules of the kidney reabsorb a large amount of filtered ions and solutes owing to receptor-mediated endocytosis and polarized transport systems that reflect final cell differentiation. Dedifferentiation of proximal tubule cells and dysfunction of receptor-mediated endocytosis characterize Dent's disease, a rare disorder caused by inactivating mutations in the CLCN5 gene that encodes the endosomal chloride-proton exchanger, ClC-5. The disease is characterized by a massive urinary loss of solutes (renal Fanconi syndrome), with severe metabolic complications and progressive renal failure. Investigations of mutations affecting the gating of ClC-5 revealed that the proximal tubule dysfunction may occur despite normal endosomal acidification. In addition to defective endocytosis, proximal tubule cells lacking ClC-5 show a trafficking defect in apical receptors and transporters, as well as lysosomal dysfunction and typical features of dedifferentiation, proliferation and oxidative stress. A similar but milder defect is observed in mouse models with defective CFTR, a chloride channel that is also expressed in the endosomes of proximal tubule cells. These data suggest a major role for endosomal chloride transport in the maintenance of epithelial differentiation and reabsorption capacity of the renal proximal tubule.
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Affiliation(s)
- Olivier Devuyst
- Institute of Physiology, Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland
| | - Alessandro Luciani
- Institute of Physiology, Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland
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Norden AGW, Lapsley M, Unwin RJ. Urine retinol-binding protein 4: a functional biomarker of the proximal renal tubule. Adv Clin Chem 2014; 63:85-122. [PMID: 24783352 DOI: 10.1016/b978-0-12-800094-6.00003-0] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Measurement of retinol-binding protein 4 in urine (uRBP4) is arguably the most sensitive biomarker for loss of function of the human proximal renal tubule. Megalin- and cubilin-receptor-mediated endocytosis normally absorbs > 99% of the approximately 1.5 g/24 h of protein filtered by the renal glomerulus. When this fails there is "tubular proteinuria," comprising uRBP4, albumin, and many other proteins and peptides. This tubular proteinuria is a consistent feature of the renal Fanconi syndrome (FS) and measurement of uRBP4 appears to be an excellent screening test for FS. FS occurs in rare inherited renal diseases including cystinosis, Dent disease, Lowe syndrome, and autosomal dominant FS. Acquired FS occurs in paraproteinemias, tubulointerstitial renal disease, oncogenic osteomalacia, Chinese herbs nephropathy, and Balkan endemic nephropathy. Though poorly understood, FS may be associated with HIV disease and antiretroviral treatment; cadmium poisoning may cause FS. In addition to FS, uRBP4 measurement has a different role: the early detection of acute kidney injury. Urine RBP4 comprises several isoforms, including intact plasma RBP4, MW 21.07 kDa, and C-terminal truncated forms, des-L- and des-LL-RBP4, also probably plasma derived. In FS, uRBP4 levels are about 104-fold above the upper limit of normal and small increments are frequently seen in carriers of some inherited forms of FS and in acquired disease. The very high levels in disease, frequent assay nonlinearity, lack of defined calibrants, and multiple uRBP4 isoforms make accurate assay challenging; top-down mass spectrometry has brought advances. Assays for uRBP4 with defined molecular targets allowing good interlaboratory comparisons are needed.
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Anastasakis A, Plainis S, Giannakopoulou T, Papadimitraki E, Fanouriakis C, Tsilimbaris MK. Xerophthalmia and acquired night blindness in a patient with a history of gastrointestinal neoplasia and normal serum vitamin A levels. Doc Ophthalmol 2013; 126:159-62. [DOI: 10.1007/s10633-012-9370-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Accepted: 12/18/2012] [Indexed: 11/28/2022]
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