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Culver SA, Suleman N, Kavuru V, Siragy HM. Renal Hypokalemia: An Endocrine Perspective. J Clin Endocrinol Metab 2024; 109:1694-1706. [PMID: 38546505 DOI: 10.1210/clinem/dgae201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Indexed: 06/18/2024]
Abstract
The majority of disorders that cause renal potassium wasting present with abnormalities in adrenal hormone secretion. While these findings frequently lead patients to seek endocrine evaluation, clinicians often struggle to accurately diagnose these conditions, delaying treatment and adversely impacting patient care. At the same time, growing insight into the genetic and molecular basis of these disorders continues to improve their diagnosis and management. In this review, we outline a practical integrated approach to the evaluation of renal hypokalemia syndromes that are seen in endocrine practice while highlighting recent advances in understanding of the genetics and pathophysiology behind them.
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Affiliation(s)
- Silas A Culver
- Division of Endocrinology, Department of Medicine, University of Virginia Health System, Charlottesville, VA 22908, USA
| | - Nawar Suleman
- Division of Endocrinology, Department of Medicine, University of Virginia Health System, Charlottesville, VA 22908, USA
| | - Varun Kavuru
- Department of Medicine, University of Virginia Health System, Charlottesville, VA 22908, USA
| | - Helmy M Siragy
- Division of Endocrinology, Department of Medicine, University of Virginia Health System, Charlottesville, VA 22908, USA
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Kumar R, Shreshta N, Samdarshi S, Chauhan P. Bartter syndrome-like phenotype in a patient with type 2 diabetes mellitus. BMJ Case Rep 2024; 17:e257953. [PMID: 38350705 PMCID: PMC10868243 DOI: 10.1136/bcr-2023-257953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2024] Open
Abstract
Bartter syndrome (BS) is a rare genetic tubulopathy affecting the loop of Henle leading to salt wasting. It is commonly seen in utero or in the early neonatal period. Rare cases of acquired BS are reported in association with infections like tuberculosis, granulomatous conditions like sarcoidosis, autoimmune diseases and drugs. The mainstay of management includes potassium, calcium and magnesium supplementation. We report the case of a woman in her 50s with a history of type 2 diabetes mellitus for the last 10 years, who presented with diabetic foot ulcers and generalised weakness with ECG changes suggestive of hypokalaemia. She had severe hypokalaemia with high urine potassium excretion and hypochloraemic metabolic alkalosis. She poorly responded to intravenously administered potassium supplements and had persistent hypokalaemia. On further evaluation of the persistent hypokalaemia, a diagnosis of idiopathic Bartter-like phenotype was made. She responded well to tablet indomethacin and is presently asymptomatic and is being maintained on tablet indomethacin after 6 months of follow-up.
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Affiliation(s)
- Ravi Kumar
- Internal Medicine, Armed Forces Medical College, Pune, India
| | - Nirmal Shreshta
- Internal Medicine, Armed Forces Medical College, Pune, India
| | - Samir Samdarshi
- Internal Medicine, Armed Forces Medical College, Pune, India
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Kwon HC, Fairclough RH, Chen TY. Biophysical and Pharmacological Insights to CLC Chloride Channels. Handb Exp Pharmacol 2024; 283:1-34. [PMID: 35768555 DOI: 10.1007/164_2022_594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The CLC family encompasses two functional categories of transmembrane proteins: chloride conducting channels and proton-chloride antiporters. All members in this chloride channel/transporter family consist of two identical protein subunits, and each subunit forms an independent ion-transport pathway, a structural architecture known as "double barrel." These CLC proteins serve biological functions ranging from membrane excitability and cell volume regulation to acidification of endosomes. Despite their ubiquitous expression, physiological significance, and resolved molecular structures of some of the family members, the mechanisms governing these molecules' biophysical functions are still not completely settled. However, a series of functional and structural studies have brought insights into interesting questions related to these proteins. This chapter explores the functional peculiarities underlying CLC channels aided by information observed from the chloride-proton antiporters in the CLC family. The overall structural features of these CLC proteins will be presented, and the biophysical functions will be addressed. Finally, the mechanism of pharmacological agents that interact with CLC channels will also be discussed.
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Affiliation(s)
- Hwoi Chan Kwon
- Center for Neuroscience and Biophysics Graduate Group, University of California, Davis, CA, USA
| | - Robert H Fairclough
- Department of Neurology and the Biophysics Graduate Group, University of California, Davis, CA, USA
| | - Tsung-Yu Chen
- Center for Neuroscience, Department of Neurology, and Biophysics Graduate Group, University of California, Davis, CA, USA.
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Yang G, Mack H, Harraka P, Colville D, Savige J. Ocular manifestations of the genetic renal tubulopathies. Ophthalmic Genet 2023; 44:515-529. [PMID: 37702059 DOI: 10.1080/13816810.2023.2253901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 08/26/2023] [Indexed: 09/14/2023]
Abstract
BACKGROUND The genetic tubulopathies are rare and heterogenous disorders that are often difficult to identify. This study examined the tubulopathy-causing genes for ocular associations that suggested their genetic basis and, in some cases, the affected gene. METHODS Sixty-seven genes from the Genomics England renal tubulopathy panel were reviewed for ocular features, and for retinal expression in the Human Protein Atlas and an ocular phenotype in mouse models in the Mouse Genome Informatics database. The genes resulted in disease affecting the proximal tubules (n = 24); the thick ascending limb of the loop of Henle (n = 10); the distal convoluted tubule (n = 15); or the collecting duct (n = 18). RESULTS Twenty-five of the tubulopathy-associated genes (37%) had ocular features reported in human disease, 49 (73%) were expressed in the retina, although often at low levels, and 16 (24%) of the corresponding mouse models had an ocular phenotype. Ocular abnormalities were more common in genes affected in the proximal tubulopathies (17/24, 71%) than elsewhere (7/43, 16%). They included structural features (coloboma, microphthalmia); refractive errors (myopia, astigmatism); crystal deposition (in oxalosis, cystinosis) and sclerochoroidal calcification (in Bartter, Gitelman syndromes). Retinal atrophy was common in the mitochondrial-associated tubulopathies. Structural abnormalities and crystal deposition were present from childhood, but sclerochoroidal calcification typically occurred after middle age. CONCLUSIONS Ocular abnormalities are uncommon in the genetic tubulopathies but may be helpful in recognizing the underlying genetic disease. The retinal expression and mouse phenotype data suggest that further ocular associations may become apparent with additional reports. Early identification may be necessary to monitor and treat visual complications.
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Affiliation(s)
- GeFei Yang
- Department of Medicine (Melbourne Health and Northern Health), The University of Melbourne, Royal Melbourne Hospital, Parkville, Australia
| | - Heather Mack
- Department of Surgery (Ophthalmology), The University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia
| | - Philip Harraka
- Department of Medicine (Melbourne Health and Northern Health), The University of Melbourne, Royal Melbourne Hospital, Parkville, Australia
| | - Deb Colville
- Department of Surgery (Ophthalmology), The University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia
| | - Judy Savige
- Department of Medicine (Melbourne Health and Northern Health), The University of Melbourne, Royal Melbourne Hospital, Parkville, Australia
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Clemente-Suárez VJ, Martín-Rodríguez A, Redondo-Flórez L, Villanueva-Tobaldo CV, Yáñez-Sepúlveda R, Tornero-Aguilera JF. Epithelial Transport in Disease: An Overview of Pathophysiology and Treatment. Cells 2023; 12:2455. [PMID: 37887299 PMCID: PMC10605148 DOI: 10.3390/cells12202455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 10/11/2023] [Accepted: 10/13/2023] [Indexed: 10/28/2023] Open
Abstract
Epithelial transport is a multifaceted process crucial for maintaining normal physiological functions in the human body. This comprehensive review delves into the pathophysiological mechanisms underlying epithelial transport and its significance in disease pathogenesis. Beginning with an introduction to epithelial transport, it covers various forms, including ion, water, and nutrient transfer, followed by an exploration of the processes governing ion transport and hormonal regulation. The review then addresses genetic disorders, like cystic fibrosis and Bartter syndrome, that affect epithelial transport. Furthermore, it investigates the involvement of epithelial transport in the pathophysiology of conditions such as diarrhea, hypertension, and edema. Finally, the review analyzes the impact of renal disease on epithelial transport and highlights the potential for future research to uncover novel therapeutic interventions for conditions like cystic fibrosis, hypertension, and renal failure.
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Affiliation(s)
- Vicente Javier Clemente-Suárez
- Faculty of Sports Sciences, Universidad Europea de Madrid, Tajo Street, s/n, 28670 Madrid, Spain;
- Group de Investigación en Cultura, Educación y Sociedad, Universidad de la Costa, Barranquilla 080002, Colombia
| | | | - Laura Redondo-Flórez
- Department of Health Sciences, Faculty of Biomedical and Health Sciences, Universidad Europea de Madrid, C/Tajo s/n, Villaviciosa de Odón, 28670 Madrid, Spain; (L.R.-F.); (C.V.V.-T.)
| | - Carlota Valeria Villanueva-Tobaldo
- Department of Health Sciences, Faculty of Biomedical and Health Sciences, Universidad Europea de Madrid, C/Tajo s/n, Villaviciosa de Odón, 28670 Madrid, Spain; (L.R.-F.); (C.V.V.-T.)
| | - Rodrigo Yáñez-Sepúlveda
- Faculty of Education and Social Sciences, Universidad Andres Bello, Viña del Mar 2520000, Chile;
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Hernández NEG, Pérez LIE, Aguilera D, Camargo-Muñiz MD, Espinosa CFC, Jaramillo MDLCR, Salvador C, González ZL, Hureaux M, Vargas-Poussou R. Clinical Findings and Genetic Analysis of Nine Mexican Families with Bartter Syndrome. Arch Med Res 2023; 54:102859. [PMID: 37516009 DOI: 10.1016/j.arcmed.2023.102859] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 06/26/2023] [Accepted: 07/04/2023] [Indexed: 07/31/2023]
Abstract
BACKGROUND Bartter's syndrome (BS) is a group of salt-wasting tubulopathies characterized by hypokalemia, metabolic alkalosis, hypercalciuria, secondary hyperaldosteronism, and low or normal blood pressure. Loss-of-function variants in genes encoding for five proteins expressed in the thick ascending limb of Henle in the nephron, produced different genetic types of BS. AIM Clinical and genetic analysis of families with Antenatal Bartter syndrome (ABS) and with Classic Bartter syndrome (CBS). METHODS Nine patients from unrelated non-consanguineous Mexican families were studied. Massive parallel sequencing of a gene panel or whole-exome sequencing was used to identify the causative gene. RESULTS Proband 1 was homozygous for the pathogenic variant p.Arg302Gln in the SLC12A1 gene encoding for the sodium-potassium-chloride NKCC2 cotransporter. Proband 3 was homozygous for the nonsense variant p.Cys308* in the KCNJ1 gene encoding for the ROMK potassium channel. Probands 7, 8, and 9 showed variants in the CLCKNB gene encoding the chloride channel ClC-Kb: proband 7 was compound heterozygous for the deletion of the entire gene and the missense change p.Arg438Cys; proband 8 presented a homozygous deletion of the whole gene and proband 9 was homozygous for the nonsense mutation p.Arg595*. A heterozygous variant of unknown significance was detected in the SLC12A1 gene in proband 2, and no variants were found in SLC12A1, KCNJ1, BSND, CLCNKA, CLCNKB, and MAGED2 genes in probands 4, 5, and 6. CONCLUSIONS Genetic analysis identified loss-of-function variants in the SLC12A1, KCNJ1, and CLCNKB genes in four patients with ABS and in the CLCNKB gene in two patients with CBS.
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Affiliation(s)
- Norma E Guerra Hernández
- Pediatric Nephrology Service, General Hospital of the National Medical Center, La Raza, Instituto Mexicano del Seguro Social, Mexico City, Mexico
| | - Laura I Escobar Pérez
- Department of Physiology of the School of Medicine, Universidad Nacional Autónoma de México, Mexico City, Mexico.
| | - Dora Aguilera
- Pediatric Nephrology Service, General Hospital of the National Medical Center, La Raza, Instituto Mexicano del Seguro Social, Mexico City, Mexico
| | - María Dolores Camargo-Muñiz
- Department of Pediatrics, Northeast National Medical Center, High Specialty Medical Unit No. 25, Instituto Mexicano del Seguro Social, Monterrey, N.L., Mexico
| | | | | | - Carolina Salvador
- Department of Physiology of the School of Medicine, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Zinaeli López González
- Department of Physiology of the School of Medicine, Universidad Nacional Autónoma de México, Mexico City, Mexico
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Tschernoster N, Erger F, Kohl S, Reusch B, Wenzel A, Walsh S, Thiele H, Becker C, Franitza M, Bartram MP, Kömhoff M, Schumacher L, Kukat C, Borodina T, Quedenau C, Nürnberg P, Rinschen MM, Driller JH, Pedersen BP, Schlingmann KP, Hüttel B, Bockenhauer D, Beck B, Altmüller J. Long-read sequencing identifies a common transposition haplotype predisposing for CLCNKB deletions. Genome Med 2023; 15:62. [PMID: 37612755 PMCID: PMC10464140 DOI: 10.1186/s13073-023-01215-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 07/27/2023] [Indexed: 08/25/2023] Open
Abstract
BACKGROUND Long-read sequencing is increasingly used to uncover structural variants in the human genome, both functionally neutral and deleterious. Structural variants occur more frequently in regions with a high homology or repetitive segments, and one rearrangement may predispose to additional events. Bartter syndrome type 3 (BS 3) is a monogenic tubulopathy caused by deleterious variants in the chloride channel gene CLCNKB, a high proportion of these being large gene deletions. Multiplex ligation-dependent probe amplification, the current diagnostic gold standard for this type of mutation, will indicate a simple homozygous gene deletion in biallelic deletion carriers. However, since the phenotypic spectrum of BS 3 is broad even among biallelic deletion carriers, we undertook a more detailed analysis of precise breakpoint regions and genomic structure. METHODS Structural variants in 32 BS 3 patients from 29 families and one BS4b patient with CLCNKB deletions were investigated using long-read and synthetic long-read sequencing, as well as targeted long-read sequencing approaches. RESULTS We report a ~3 kb duplication of 3'-UTR CLCNKB material transposed to the corresponding locus of the neighbouring CLCNKA gene, also found on ~50 % of alleles in healthy control individuals. This previously unknown common haplotype is significantly enriched in our cohort of patients with CLCNKB deletions (45 of 51 alleles with haplotype information, 2.2 kb and 3.0 kb transposition taken together, p=9.16×10-9). Breakpoint coordinates for the CLCNKB deletion were identifiable in 28 patients, with three being compound heterozygous. In total, eight different alleles were found, one of them a complex rearrangement with three breakpoint regions. Two patients had different CLCNKA/CLCNKB hybrid genes encoding a predicted CLCNKA/CLCNKB hybrid protein with likely residual function. CONCLUSIONS The presence of multiple different deletion alleles in our cohort suggests that large CLCNKB gene deletions originated from many independently recurring genomic events clustered in a few hot spots. The uncovered associated sequence transposition haplotype apparently predisposes to these additional events. The spectrum of CLCNKB deletion alleles is broader than expected and likely still incomplete, but represents an obvious candidate for future genotype/phenotype association studies. We suggest a sensitive and cost-efficient approach, consisting of indirect sequence capture and long-read sequencing, to analyse disease-relevant structural variant hotspots in general.
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Affiliation(s)
- Nikolai Tschernoster
- Cologne Center for Genomics (CCG), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
- Institute of Human Genetics, Faculty of Medicine and University Hospital Cologne, University of Cologne, Kerpener Str. 34, 50931, Cologne, Germany
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Florian Erger
- Institute of Human Genetics, Faculty of Medicine and University Hospital Cologne, University of Cologne, Kerpener Str. 34, 50931, Cologne, Germany
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Stefan Kohl
- Department of Pediatrics, Cologne Children's Hospital, Cologne, Germany
| | - Björn Reusch
- Institute of Human Genetics, Faculty of Medicine and University Hospital Cologne, University of Cologne, Kerpener Str. 34, 50931, Cologne, Germany
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Andrea Wenzel
- Institute of Human Genetics, Faculty of Medicine and University Hospital Cologne, University of Cologne, Kerpener Str. 34, 50931, Cologne, Germany
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Stephen Walsh
- Department of Renal Medicine, UCL, University College London, London, UK
| | - Holger Thiele
- Cologne Center for Genomics (CCG), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Christian Becker
- Cologne Center for Genomics (CCG), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Marek Franitza
- Cologne Center for Genomics (CCG), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Malte P Bartram
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
- Department II of Internal Medicine, University of Cologne, Cologne, Germany
| | - Martin Kömhoff
- Department of Pediatrics, University Marburg, Marburg, Germany
| | - Lena Schumacher
- FACS & Imaging Core Facility, Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Christian Kukat
- FACS & Imaging Core Facility, Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Tatiana Borodina
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Hannoversche Straße 28, 10115, Berlin, Germany
| | - Claudia Quedenau
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Hannoversche Straße 28, 10115, Berlin, Germany
| | - Peter Nürnberg
- Cologne Center for Genomics (CCG), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Markus M Rinschen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
- Aarhus Institute of Advanced Studies, Aarhus University, Aarhus, Denmark
- Department III of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Jan H Driller
- Department of Molecular Biology and Genetics, Aarhus University, Universitetsbyen 81, DK-8000, Aarhus C, Denmark
| | - Bjørn P Pedersen
- Department of Molecular Biology and Genetics, Aarhus University, Universitetsbyen 81, DK-8000, Aarhus C, Denmark
| | - Karl P Schlingmann
- Department of General Pediatrics, University Children's Hospital, Münster, Germany
| | - Bruno Hüttel
- Max Planck Genome-Centre Cologne, Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - Detlef Bockenhauer
- Department of Renal Medicine, UCL, University College London, London, UK
- Great Ormond Street Hospital for Children, NHS Foundation Trust, London, UK
| | - Bodo Beck
- Institute of Human Genetics, Faculty of Medicine and University Hospital Cologne, University of Cologne, Kerpener Str. 34, 50931, Cologne, Germany.
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.
| | - Janine Altmüller
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Hannoversche Straße 28, 10115, Berlin, Germany.
- Berlin Institute of Health at Charité - Universitätsmedizin Berlin, Core Facility Genomics, Berlin, Germany.
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García-Castaño A, Gómez-Conde S, Gondra L, Herrero M, Aguirre M, de la Hoz AB, Castaño L, Madariaga L. Genotypic variability in patients with clinical diagnosis of Bartter syndrome type 3. Sci Rep 2023; 13:12587. [PMID: 37537162 PMCID: PMC10400606 DOI: 10.1038/s41598-023-38179-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 07/04/2023] [Indexed: 08/05/2023] Open
Abstract
Bartter syndrome (BS) is a salt-losing hereditary tubulopathy characterized by hypokalemic metabolic alkalosis with secondary hyperaldosteronism. Confirmatory molecular diagnosis may be difficult due to genetic heterogeneity and overlapping of clinical symptoms. The aim of our study was to describe the different molecular findings in patients with a clinical diagnosis of classic BS. We included 27 patients (26 families) with no identified pathogenic variants in CLCNKB. We used a customized Ion AmpliSeq Next-Generation Sequencing panel including 44 genes related to renal tubulopathies. We detected pathogenic or likely pathogenic variants in 12 patients (44%), reaching a conclusive genetic diagnosis. Variants in SLC12A3 were found in 6 (Gitelman syndrome). Median age at diagnosis was 14.6 years (range 0.1-31), with no history of prematurity or polyhydramnios. Serum magnesium level was low in 2 patients (33%) but urinary calcium excretion was normal or low in all, with no nephrocalcinosis. Variants in SLC12A1 were found in 3 (BS type 1); and in KCNJ1 in 1 (BS type 2). These patients had a history of polyhydramnios in 3 (75%), and the mean gestational age was 34.2 weeks (SD 1.7). The median age at diagnosis was 1.8 years (range 0.1-6). Chronic kidney disease and nephrocalcinosis were present in 1 (25%) and 3 (75%) patients, respectively. A variant in CLCN5 was found in one patient (Dent disease), and in NR3C2 in another patient (Geller syndrome). Genetic diagnosis of BS is heterogeneous as different tubulopathies can present with a similar clinical picture. The use of gene panels in these diseases becomes more efficient than the study gene by gene with Sanger sequencing.
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Affiliation(s)
- Alejandro García-Castaño
- Biocruces Bizkaia Health Research Institute, Barakaldo, Spain
- CIBERDEM, CIBERER, Endo-ERN, Madrid, Spain
| | - Sara Gómez-Conde
- Biocruces Bizkaia Health Research Institute, Barakaldo, Spain
- CIBERDEM, CIBERER, Endo-ERN, Madrid, Spain
- Pediatric Department, University of the Basque Country UPV/EHU, Bizkaia, Spain
| | - Leire Gondra
- Biocruces Bizkaia Health Research Institute, Barakaldo, Spain
- CIBERDEM, CIBERER, Endo-ERN, Madrid, Spain
- Pediatric Department, University of the Basque Country UPV/EHU, Bizkaia, Spain
- Pediatric Nephrology Department, Cruces University Hospital, Plaza de Cruces, 48903, Barakaldo, Bizkaia, Spain
| | - María Herrero
- Biocruces Bizkaia Health Research Institute, Barakaldo, Spain
- Pediatric Nephrology Department, Cruces University Hospital, Plaza de Cruces, 48903, Barakaldo, Bizkaia, Spain
| | - Mireia Aguirre
- Biocruces Bizkaia Health Research Institute, Barakaldo, Spain
- Pediatric Nephrology Department, Cruces University Hospital, Plaza de Cruces, 48903, Barakaldo, Bizkaia, Spain
| | - Ana-Belén de la Hoz
- Biocruces Bizkaia Health Research Institute, Barakaldo, Spain
- CIBERDEM, CIBERER, Endo-ERN, Madrid, Spain
| | - Luis Castaño
- Biocruces Bizkaia Health Research Institute, Barakaldo, Spain
- CIBERDEM, CIBERER, Endo-ERN, Madrid, Spain
- Pediatric Department, University of the Basque Country UPV/EHU, Bizkaia, Spain
| | - Leire Madariaga
- Biocruces Bizkaia Health Research Institute, Barakaldo, Spain.
- CIBERDEM, CIBERER, Endo-ERN, Madrid, Spain.
- Pediatric Department, University of the Basque Country UPV/EHU, Bizkaia, Spain.
- Pediatric Nephrology Department, Cruces University Hospital, Plaza de Cruces, 48903, Barakaldo, Bizkaia, Spain.
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9
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Choi N, Kim SH, Bae EH, Yang EM, Lee GH, Lee SH, Lee JH, Ahn YH, Cheong HI, Kang HG, Hyun HS, Kim JH. Long-term outcome of Bartter syndrome in 54 patients: A multicenter study in Korea. Front Med (Lausanne) 2023; 10:1099840. [PMID: 36993809 PMCID: PMC10040751 DOI: 10.3389/fmed.2023.1099840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 02/16/2023] [Indexed: 03/14/2023] Open
Abstract
IntroductionBartter syndrome (BS) is a rare salt-wasting tubulopathy caused by mutations in genes encoding sodium, potassium, or chloride transporters of the thick ascending limb of the loop of Henle and/or the distal convoluted tubule of the kidney. BS is characterized by polyuria, failure to thrive, hypokalemia, metabolic alkalosis, hyperreninemia, and hyperaldosteronism. Potassium and/or sodium supplements, potassium-sparing diuretics, and nonsteroidal anti-inflammatory drugs can be used to treat BS. While its symptoms and initial management are relatively well known, long-term outcomes and treatments are scarce.MethodsWe retrospectively reviewed 54 Korean patients who were clinically or genetically diagnosed with BS from seven centers in Korea.ResultsAll patients included in this study were clinically or genetically diagnosed with BS at a median age of 5 (range, 0–271) months, and their median follow-up was 8 (range, 0.5–27) years. Genetic diagnosis of BS was confirmed in 39 patients: 4 had SLC12A1 gene mutations, 1 had KCNJ1 gene mutations, 33 had CLCNKB gene mutations, and 1 had BSND mutation. Potassium chloride supplements and potassium-sparing diuretics were administered in 94% and 68% of patients, respectively. The mean dosage of potassium chloride supplements was 5.0 and 2.1 mEq/day/kg for patients younger and older than 18 years, respectively. Nephrocalcinosis was a common finding of BS, and it also improved with age in some patients. At the last follow-up of 8 years after the initial diagnosis, 41% had short stature (height less than 3rd percentile) and impaired kidney function was observed in six patients [chronic kidney disease (CKD) G3, n = 4; CKD G5, n = 2].ConclusionBS patients require a large amount of potassium supplementation along with potassium-sparing agents throughout their lives, but tend to improve with age. Despite management, a significant portion of this population exhibited growth impairment, while 11% developed CKD G3–G5.
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Affiliation(s)
- Naye Choi
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Republic of Korea
- Department of Pediatrics, Seoul National University Children's Hospital, Seoul, Republic of Korea
| | - Seong Heon Kim
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Republic of Korea
- Department of Pediatrics, Seoul National University Children's Hospital, Seoul, Republic of Korea
| | - Eun Hui Bae
- Department of Internal Medicine, Medical School, Chonnam National University, Gwangju, Republic of Korea
| | - Eun Mi Yang
- Department of Pediatrics, Chonnam National University Hospital, Gwangju, Republic of Korea
| | - Geum Hwa Lee
- Department of Pediatrics, Yonsei University Severance Children's Hospital, Seoul, Republic of Korea
| | - Sang-Ho Lee
- Department of Internal Medicine, Kyung Hee University Hospital at Gangdong, Seoul, Republic of Korea
| | - Joo Hoon Lee
- Department of Pediatrics, Ulsan University Asan Medical Center, Seoul, Republic of Korea
| | - Yo Han Ahn
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Republic of Korea
- Department of Pediatrics, Seoul National University Children's Hospital, Seoul, Republic of Korea
- Kidney Research Institute, Seoul National University Medical Research Center, Seoul, Republic of Korea
| | - Hae Il Cheong
- Department of Pediatrics, Hallym University Sacred Heart Hospital, Anyang, Republic of Korea
| | - Hee Gyung Kang
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Republic of Korea
- Department of Pediatrics, Seoul National University Children's Hospital, Seoul, Republic of Korea
- Kidney Research Institute, Seoul National University Medical Research Center, Seoul, Republic of Korea
- Wide River Institute of Immunology, Seoul National University, Hongcheon, Republic of Korea
| | - Hye Sun Hyun
- Department of Pediatrics, Collage of Medicine, St. Vincent's Hospital, The Catholic University of Korea, Seoul, Republic of Korea
- *Correspondence: Hye Sun Hyun,
| | - Ji Hyun Kim
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Republic of Korea
- Department of Pediatrics, Seoul National University Bundang Hospital, Seongnam, Republic of Korea
- Ji Hyun Kim,
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10
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Vaisbich MH, Messa ACHL, Rangel-Santos AC, Ferreira JCDOA, Nunes FAMDF, Watanabe A. Bartter Syndrome-Related Variants Distribution: Brazilian Data and Its Comparison with Worldwide Cohorts. Nephron Clin Pract 2023; 147:478-495. [PMID: 36882007 DOI: 10.1159/000528557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Accepted: 11/28/2022] [Indexed: 03/09/2023] Open
Abstract
BACKGROUND Genetic testing is recommended for accurate diagnosis of Bartter syndrome (BS) and serves as a basis for implementing specific target therapies. However, populations other than Europeans and North Americans are underrepresented in most databases and there are uncertainties in the genotype-phenotype correlation. We studied Brazilian BS patients, an admixed population with diverse ancestry. METHODS We evaluated the clinical and mutational profile of this cohort and performed a systematic review of BS mutations from worldwide cohorts. RESULTS Twenty-two patients were included; Gitelman syndrome was diagnosed in 2 siblings with antenatal BS and congenital chloride diarrhea in 1 girl. BS was confirmed in 19 patients: BS type 1 in 1 boy (antenatal BS); BS type 4a in 1 girl and BS type 4b in 1 girl, both of them with antenatal BS and neurosensorial deafness; BS type 3 (CLCNKB mutations): 16 cases. The deletion of the entire CLCNKB (1-20 del) was the most frequent variant. Patients carrying the 1-20 del presented earlier manifestations than those with other CLCNKB-mutations and the presence of homozygous 1-20 del was correlated with progressive chronic kidney disease. The prevalence of the 1-20 del in this BS Brazilian cohort was similar to that of Chinese cohorts and individuals of African and Middle Eastern descent from other cohorts. CONCLUSION This study expands the genetic spectrum of BS patients with different ethnics, reveals some genotype/phenotype correlations, compares the findings with other cohorts, and provides a systematic review of the literature on the distribution of BS-related variants worldwide.
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Affiliation(s)
- Maria Helena Vaisbich
- Instituto da Criança do Hospital das Clínicas da Faculdade de Medicina da USP, São Paulo, Brazil
| | | | | | | | | | - Andreia Watanabe
- Instituto da Criança do Hospital das Clínicas da Faculdade de Medicina da USP, São Paulo, Brazil
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11
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Guo W, Ji P, Xie Y. Genetic diagnosis and treatment of hereditary renal tubular disease with hypokalemia and alkalosis. J Nephrol 2023; 36:575-591. [PMID: 35994232 DOI: 10.1007/s40620-022-01428-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 07/29/2022] [Indexed: 10/15/2022]
Abstract
Renal tubules play an important role in maintaining water, electrolyte, and acid-base balance. Renal tubule dysfunction can cause electrolyte disorders and acid-base imbalance. Clinically, hypokalemic renal tubular disease is the most common tubule disorder. With the development of molecular genetics and gene sequencing technology, hereditary renal tubular diseases have attracted attention, and an increasing number of pathogenic genes related to renal tubular diseases have been discovered and reported. Inherited renal tubular diseases mainly occur due to mutations in genes encoding various specific transporters or ion channels expressed on the tubular epithelial membrane, leading to dysfunctional renal tubular reabsorption, secretion, and excretion. An in-depth understanding of the molecular genetic basis of hereditary renal tubular disease will help to understand the physiological function of renal tubules, the mechanism by which the kidney maintains water, electrolyte, and acid-base balance, and the relationship between the kidney and other systems in the body. Meanwhile, understanding these diseases also improves our understanding of the pathogenesis of hypokalemia, alkalosis and other related diseases and ultimately promotes accurate diagnostics and effective disease treatment. The present review summarizes the most common hereditary renal tubular diseases (Bartter syndrome, Gitelman syndrome, EAST syndrome and Liddle syndrome) characterized by hypokalemia and alkalosis. Further detailed explanations are provided for pathogenic genes and functional proteins, clinical manifestations, intrinsic relationship between genotype and clinical phenotype, diagnostic clues, differential diagnosis, and treatment strategies for these diseases.
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Affiliation(s)
- Wenkai Guo
- Department of Nephrology, First Medical Center of Chinese PLA General Hospital, Chinese PLA Institute of Nephrology, State Key Laboratory of Kidney Diseases, National Clinical Research Center for Kidney Diseases, Beijing, 100853, People's Republic of China
- School of Medicine, Nankai University, Tianjin, 300071, People's Republic of China
| | - Pengcheng Ji
- Department of Nephrology, First Medical Center of Chinese PLA General Hospital, Chinese PLA Institute of Nephrology, State Key Laboratory of Kidney Diseases, National Clinical Research Center for Kidney Diseases, Beijing, 100853, People's Republic of China
| | - Yuansheng Xie
- Department of Nephrology, First Medical Center of Chinese PLA General Hospital, Chinese PLA Institute of Nephrology, State Key Laboratory of Kidney Diseases, National Clinical Research Center for Kidney Diseases, Beijing, 100853, People's Republic of China.
- School of Medicine, Nankai University, Tianjin, 300071, People's Republic of China.
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12
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Abstract
Mg2+ is essential for many cellular and physiological processes, including muscle contraction, neuronal activity, and metabolism. Consequently, the blood Mg2+ concentration is tightly regulated by balanced intestinal Mg2+ absorption, renal Mg2+ excretion, and Mg2+ storage in bone and soft tissues. In recent years, the development of novel transgenic animal models and identification of Mendelian disorders has advanced our current insight in the molecular mechanisms of Mg2+ reabsorption in the kidney. In the proximal tubule, Mg2+ reabsorption is dependent on paracellular permeability by claudin-2/12. In the thick ascending limb of Henle's loop, the claudin-16/19 complex provides a cation-selective pore for paracellular Mg2+ reabsorption. The paracellular Mg2+ reabsorption in this segment is regulated by the Ca2+-sensing receptor, parathyroid hormone, and mechanistic target of rapamycin (mTOR) signaling. In the distal convoluted tubule, the fine tuning of Mg2+ reabsorption takes place by transcellular Mg2+ reabsorption via transient receptor potential melastatin-like types 6 and 7 (TRPM6/TRPM7) divalent cation channels. Activity of TRPM6/TRPM7 is dependent on hormonal regulation, metabolic activity, and interacting proteins. Basolateral Mg2+ extrusion is still poorly understood but is probably dependent on the Na+ gradient. Cyclin M2 and SLC41A3 are the main candidates to act as Na+/Mg2+ exchangers. Consequently, disturbances of basolateral Na+/K+ transport indirectly result in impaired renal Mg2+ reabsorption in the distal convoluted tubule. Altogether, this review aims to provide an overview of the molecular mechanisms of Mg2+ reabsorption in the kidney, specifically focusing on transgenic mouse models and human hereditary diseases.
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Affiliation(s)
- Jeroen H F de Baaij
- Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands
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13
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Viering DH, Hureaux M, Neveling K, Latta F, Kwint M, Blanchard A, Konrad M, Bindels RJ, Schlingmann KP, Vargas-Poussou R, de Baaij JH. Long-Read Sequencing Identifies Novel Pathogenic Intronic Variants in Gitelman Syndrome. J Am Soc Nephrol 2023; 34:333-345. [PMID: 36302598 PMCID: PMC10103101 DOI: 10.1681/asn.2022050627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 10/17/2022] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Gitelman syndrome is a salt-losing tubulopathy characterized by hypokalemic alkalosis and hypomagnesemia. It is caused by homozygous recessive or compound heterozygous pathogenic variants in SLC12A3 , which encodes the Na + -Cl - cotransporter (NCC). In up to 10% of patients with Gitelman syndrome, current genetic techniques detect only one specific pathogenic variant. This study aimed to identify a second pathogenic variant in introns, splice sites, or promoters to increase the diagnostic yield. METHODS Long-read sequencing of SLC12A3 was performed in 67 DNA samples from individuals with suspected Gitelman syndrome in whom a single likely pathogenic or pathogenic variant was previously detected. In addition, we sequenced DNA samples from 28 individuals with one variant of uncertain significance or no candidate variant. Midigene splice assays assessed the pathogenicity of novel intronic variants. RESULTS A second likely pathogenic/pathogenic variant was identified in 45 (67%) patients. Those with two likely pathogenic/pathogenic variants had a more severe electrolyte phenotype than other patients. Of the 45 patients, 16 had intronic variants outside of canonic splice sites (nine variants, mostly deep intronic, six novel), whereas 29 patients had an exonic variant or canonic splice site variant. Midigene splice assays of the previously known c.1670-191C>T variant and intronic candidate variants demonstrated aberrant splicing patterns. CONCLUSION Intronic pathogenic variants explain an important part of the missing heritability in Gitelman syndrome. Long-read sequencing should be considered in diagnostic workflows for Gitelman syndrome.
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Affiliation(s)
- Daan H.H.M. Viering
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Marguerite Hureaux
- Reference Center for Hereditary Kidney and Childhood Diseases (Maladies Rénales Héréditaires de l’Enfant et de l’Adulte, MARHEA), Paris, France
- Department of Genetics, Hôpital Européen Georges-Pompidou, Assistance Publique Hôpitaux de Paris, Paris, France
- Paris CardioVascular Research Center, Institut National de la Santé et de Recherche Médicale (INSERM) U970, Paris City University, Paris, France
| | - Kornelia Neveling
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Femke Latta
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Michael Kwint
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Anne Blanchard
- Reference Center for Hereditary Kidney and Childhood Diseases (Maladies Rénales Héréditaires de l’Enfant et de l’Adulte, MARHEA), Paris, France
- Clinical Investigations Center, Hôpital Européen Georges-Pompidou, Assistance Publique Hôpitaux de Paris, Paris, France
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, University of Paris, Centre National de la Recherche Scientifique (CNRS), Paris, France
| | - Martin Konrad
- Department of General Pediatrics, University Children’s Hospital, Münster, Germany
| | - René J.M. Bindels
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | | | - Rosa Vargas-Poussou
- Reference Center for Hereditary Kidney and Childhood Diseases (Maladies Rénales Héréditaires de l’Enfant et de l’Adulte, MARHEA), Paris, France
- Department of Genetics, Hôpital Européen Georges-Pompidou, Assistance Publique Hôpitaux de Paris, Paris, France
- Clinical Investigations Center, Hôpital Européen Georges-Pompidou, Assistance Publique Hôpitaux de Paris, Paris, France
| | - Jeroen H.F. de Baaij
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
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14
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He Y, Zhou Y, Wu W, Chen Y, Ou S. Bartter syndrome with multiple renal and liver cysts: a case report. Int Urol Nephrol 2023; 55:225-228. [PMID: 35768702 DOI: 10.1007/s11255-022-03274-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 06/02/2022] [Indexed: 01/05/2023]
Affiliation(s)
- Yemei He
- Department of Nephrology, The Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan, China.,Sichuan Clinical Research Center for Nephropathy, Luzhou, Sichuan, China
| | - Yue Zhou
- Department of Nuclear Medicine, The Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan, China.,Nuclear Medicine and Molecular Imaging Key Laboratory of Sichuan Province, Luzhou, Sichuan, China.,Academician (Expert) Workstation of Sichuan Province, Luzhou, Sichuan, China
| | - Weihua Wu
- Department of Nephrology, The Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan, China.,Sichuan Clinical Research Center for Nephropathy, Luzhou, Sichuan, China
| | - Yue Chen
- Department of Nuclear Medicine, The Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan, China. .,Nuclear Medicine and Molecular Imaging Key Laboratory of Sichuan Province, Luzhou, Sichuan, China. .,Academician (Expert) Workstation of Sichuan Province, Luzhou, Sichuan, China.
| | - Santao Ou
- Department of Nephrology, The Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan, China. .,Sichuan Clinical Research Center for Nephropathy, Luzhou, Sichuan, China.
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15
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Alexander RT, Dimke H. Molecular mechanisms underlying paracellular calcium and magnesium reabsorption in the proximal tubule and thick ascending limb. Ann N Y Acad Sci 2022; 1518:69-83. [PMID: 36200584 DOI: 10.1111/nyas.14909] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Calcium and magnesium are the most abundant divalent cations in the body. The plasma level is controlled by coordinated interaction between intestinal absorption, reabsorption in the kidney, and, for calcium at least, bone storage and exchange. The kidney adjusts urinary excretion of these ions in response to alterations in their systemic concentration. Free ionized and anion-complexed calcium and magnesium are filtered at the glomerulus. The majority (i.e., >85%) of filtered divalent cations are reabsorbed via paracellular pathways from the proximal tubule and thick ascending limb (TAL) of the loop of Henle. Interestingly, the largest fraction of filtered calcium is reabsorbed from the proximal tubule (65%), while the largest fraction of filtered magnesium is reclaimed from the TAL (60%). The paracellular pathways mediating these fluxes are composed of tight junctional pores formed by claudins. In the proximal tubule, claudin-2 and claudin-12 confer calcium permeability, while the exact identity of the magnesium pore remains to be determined. Claudin-16 and claudin-19 contribute to the calcium and magnesium permeable pathway in the TAL. In this review, we discuss the data supporting these conclusions and speculate as to why there is greater fractional calcium reabsorption from the proximal tubule and greater fractional magnesium reabsorption from the TAL.
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Affiliation(s)
- R Todd Alexander
- Departments of Physiology & Pediatrics, University of Alberta, Edmonton, Alberta, Canada.,Women's and Children's Health Institute, Edmonton, Alberta, Canada
| | - Henrik Dimke
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Demark.,Department of Nephrology, Odense University Hospital, Odense, Denmark
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16
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Abstract
PURPOSE OF REVIEW Gitelman syndrome is a recessive salt-wasting disorder characterized by hypomagnesemia, hypokalemia, metabolic alkalosis and hypocalciuria. The majority of patients are explained by mutations and deletions in the SLC12A3 gene, encoding the Na+-Cl--co-transporter (NCC). Recently, additional genetic causes of Gitelman-like syndromes have been identified that should be considered in genetic screening. This review aims to provide a comprehensive overview of the clinical, genetic and mechanistic aspects of Gitelman(-like) syndromes. RECENT FINDINGS Disturbed Na+ reabsorption in the distal convoluted tubule (DCT) is associated with hypomagnesemia and hypokalemic alkalosis. In Gitelman syndrome, loss-of-function mutations in SLC12A3 cause impaired NCC-mediated Na+ reabsorption. In addition, patients with mutations in CLCKNB, KCNJ10, FXYD2 or HNF1B may present with a similar phenotype, as these mutations indirectly reduce NCC activity. Furthermore, genetic investigations of patients with Na+-wasting tubulopathy have resulted in the identification of pathogenic variants in MT-TI, MT-TF, KCNJ16 and ATP1A1. These novel findings highlight the importance of cell metabolism and basolateral membrane potential for Na+ reabsorption in the DCT. SUMMARY Altogether, these findings extend the genetic spectrum of Gitelman-like electrolyte alterations. Genetic testing of patients with hypomagnesemia and hypokalemia should cover a panel of genes involved in Gitelman-like syndromes, including the mitochondrial genome.
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Affiliation(s)
- Karl P Schlingmann
- Department of General Pediatrics, University Children's Hospital, Münster, Germany
| | - Jeroen H F de Baaij
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
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17
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Xin Q, Liu Q, Liu Z, Shi X, Liu X, Zhang R, Hong Y, Zhao X, Shao L. Twelve exonic variants in the SLC12A1 and CLCNKB genes alter RNA splicing in a minigene assay. Front Genet 2022; 13:961384. [PMID: 36092934 PMCID: PMC9452827 DOI: 10.3389/fgene.2022.961384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2022] [Accepted: 07/18/2022] [Indexed: 11/13/2022] Open
Abstract
Background: Bartter syndrome (BS) is a rare renal tubular disease caused by gene variants in SLC12A1, KCNJ1, CLCNKA, CLCNKB, BSND or MAGED2 genes. There is growing evidence that many exonic mutations can affect the pre-mRNA normal splicing and induce exon skipping by altering various splicing regulatory signals. Therefore, the aim of this study was to gain new insights into the consequences of exonic mutations associated with BS on pre-mRNA splicing.Methods: We analyzed all the missense, nonsense and synonymous variants described in six pathogenic genes by bioinformatics programs and identified candidate mutations that may promote exon skipping through a minigene system.Results: Results of the study showed that 12 of 14 candidate variants distributed in SLC12A1 (c.728G>A, C.735C>G, c.904C>T, c.905G>A, c.1304C>T, c.1493C>T, c.2221A>T) and CLCNKB (c.226C>T, c.228A>C, c.229G>A, c.229G>C, c.1979C>A) were identified to induce splicing alterations. These variants may not only disrupt exonic splicing enhancers (ESEs) but also generate new exonic splicing silencers (ESSs), or disturb the classic splicing sites.Conclusion: To our knowledge, this is a comprehensive study regarding alterations in pre-mRNA of exonic variants in BS pathogenic genes. Our results reinforce the necessity of assessing the consequences of exonic variants at the mRNA level.
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Affiliation(s)
- Qing Xin
- Department of Nephrology, the Affiliated Qingdao Municipal Hospital of Qingdao University, Qingdao, China
| | - Qihua Liu
- Department of Material Supply Management, the Affiliated Qingdao Municipal Hospital of Qingdao University, Qingdao, China
| | - Zhiying Liu
- Department of Nephrology, the Affiliated Qingdao Municipal Hospital of Qingdao University, Qingdao, China
| | - Xiaomeng Shi
- Department of Nephrology, the Affiliated Qingdao Municipal Hospital of Qingdao University, Qingdao, China
| | - Xuyan Liu
- Department of Nephrology, the Affiliated Qingdao Municipal Hospital of Qingdao University, Qingdao, China
| | - Ruixiao Zhang
- Department of Nephrology, the Affiliated Qingdao Municipal Hospital of Qingdao University, Qingdao, China
| | - Yefeng Hong
- Department of Cardiology, the Affiliated Hospital of Qingdao University, Qingdao, China
| | - Xiangzhong Zhao
- Medical Research Center, The Affiliated Hospital of Qingdao University, Qingdao, China
- *Correspondence: Xiangzhong Zhao, ; Leping Shao,
| | - Leping Shao
- Department of Nephrology, the Affiliated Qingdao Municipal Hospital of Qingdao University, Qingdao, China
- *Correspondence: Xiangzhong Zhao, ; Leping Shao,
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18
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Zhao Q, Xiang Q, Tan Y, Xiao X, Xie H, Wang H, Yang M, Liu S. A novel CLCNKB variant in a Chinese family with classic Bartter syndrome and prenatal genetic diagnosis. Mol Genet Genomic Med 2022; 10:e2027. [PMID: 35913199 PMCID: PMC9544217 DOI: 10.1002/mgg3.2027] [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: 11/25/2021] [Revised: 05/10/2022] [Accepted: 07/19/2022] [Indexed: 11/18/2022] Open
Abstract
Background Type III Bartter syndrome (BS), often known as classic Bartter syndrome is caused by variants in CLCNKB gene, which encoding the basolateral chloride channel protein ClC‐Kb, and is characterized by renal salt wasting, hypokalemia, metabolic alkalosis, increased renin, and aldosterone levels. Methods A 2‐year‐old boy presented severe malnutrition, severe metabolic alkalosis and severe hypokalemia and was clinically diagnosed with BS. The trio exome sequencing (ES) was performed to discover the genetic cause of this patient, followed by validation using Sanger sequencing and quantitative polymerase chain reaction subsequently. Results The genetic analysis indicated that this patient with a compound heterozygous variants of CLCNKB gene including a novel nonsense variant c.876 T > A and a whole‐gene deletion. The two variants were inherited from his parents, respectively. Subsequently, target sequencing of CLCNKB gene was performed for next pregnancy, and prenatal genetic diagnosis was provided for the family. Conclusions The results of current study identified the compound heterozygous variants in a patient with classic BS. The novel variant expands the spectrum of CLCNKB variants in BS. Our study also indicates that ES is an alternative tool to simultaneously detect single‐nucleotide variants and copy‐number variants.
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Affiliation(s)
- Qianying Zhao
- Department of Obstetrics & Gynecology, West China Second University Hospital, Sichuan University, Chengdu, China.,Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, Sichuan University, Chengdu, China
| | - Qinqin Xiang
- Department of Obstetrics & Gynecology, West China Second University Hospital, Sichuan University, Chengdu, China.,Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, Sichuan University, Chengdu, China
| | - Yu Tan
- Department of Obstetrics & Gynecology, West China Second University Hospital, Sichuan University, Chengdu, China.,Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, Sichuan University, Chengdu, China
| | - Xiao Xiao
- Department of Obstetrics & Gynecology, West China Second University Hospital, Sichuan University, Chengdu, China.,Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, Sichuan University, Chengdu, China
| | - Hanbing Xie
- Department of Obstetrics & Gynecology, West China Second University Hospital, Sichuan University, Chengdu, China.,Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, Sichuan University, Chengdu, China
| | - He Wang
- Department of Obstetrics & Gynecology, West China Second University Hospital, Sichuan University, Chengdu, China.,Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, Sichuan University, Chengdu, China
| | - Mei Yang
- Department of Obstetrics & Gynecology, West China Second University Hospital, Sichuan University, Chengdu, China.,Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, Sichuan University, Chengdu, China
| | - Shanling Liu
- Department of Obstetrics & Gynecology, West China Second University Hospital, Sichuan University, Chengdu, China.,Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, Sichuan University, Chengdu, China
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19
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Stevenson M, Pagnamenta AT, Mack HG, Savige J, Giacopuzzi E, Lines KE, Taylor JC, Thakker RV. The Bartter-Gitelman Spectrum: Fifty Year Follow-up with Revision of Diagnosis after Whole Genome Sequencing. J Endocr Soc 2022; 6:bvac079. [PMID: 35668994 PMCID: PMC9155595 DOI: 10.1210/jendso/bvac079] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Indexed: 11/26/2022] Open
Abstract
Bartter syndrome (BS) and Gitelman syndrome (GS) are renal tubular disorders affecting sodium, potassium, and chloride reabsorption. Clinical features include muscle cramps and weakness, in association with hypokalemia, hypochloremic metabolic alkalosis, and hyperreninemic hyperaldosteronism. Hypomagnesemia and hypocalciuria are typical of GS, while juxtaglomerular hyperplasia is characteristic of BS. GS is due to SLC12A3 variants, whereas BS is due to variants in SLC12A1, KCNJ1, CLCNKA, CLCNKB, BSND, MAGED2, or CASR. We had the opportunity to follow up one of the first reported cases of a salt-wasting tubulopathy, who based on clinical features was diagnosed with GS. The patient had presented at age 10 years with tetany precipitated by vomiting or diarrhea. She had hypokalemia, a hypochloremic metabolic alkalosis, hyponatremia, mild hypercalcemia, and normomagnesemia, and subsequently developed hypocalciuria and hypomagnesemia. A renal biopsy showed no evidence for juxtaglomerular hyperplasia. She developed chronic kidney failure at age 55 years, and ocular sclerochoroidal calcification, associated with BS and GS, at older than 65 years. Our aim was therefore to establish the genetic diagnosis in this patient using whole-genome sequencing (WGS). Leukocyte DNA was used for WGS analysis, and this revealed a homozygous c.226C > T (p.Arg76Ter) nonsense CLCNKB mutation, thereby establishing a diagnosis of BS type-3. WGS also identified 2 greater than 5-Mb regions of homozygosity that suggested likely mutational heterozygosity in her parents, who originated from a Greek island with fewer than 1500 inhabitants and may therefore have shared a common ancestor. Our results demonstrate the utility of WGS in establishing the correct diagnosis in renal tubular disorders with overlapping phenotypes.
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Affiliation(s)
- Mark Stevenson
- Academic Endocrine Unit, Oxford Centre for Diabetes, Endocrinology & Metabolism (OCDEM), Churchill Hospital, University of Oxford, Oxford, United Kingdom
- National Institute for Health Research Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Alistair T Pagnamenta
- National Institute for Health Research Oxford Biomedical Research Centre, Oxford, United Kingdom
- Wellcome Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Heather G Mack
- Department of Surgery (Ophthalmology), University of Melbourne, Parkville, Australia
| | - Judith Savige
- The University of Melbourne Department of Medicine (Melbourne Health) and Northern Health, Epping, Australia
| | - Edoardo Giacopuzzi
- National Institute for Health Research Oxford Biomedical Research Centre, Oxford, United Kingdom
- Wellcome Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Kate E Lines
- Academic Endocrine Unit, Oxford Centre for Diabetes, Endocrinology & Metabolism (OCDEM), Churchill Hospital, University of Oxford, Oxford, United Kingdom
- National Institute for Health Research Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Jenny C Taylor
- National Institute for Health Research Oxford Biomedical Research Centre, Oxford, United Kingdom
- Wellcome Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Rajesh V Thakker
- Academic Endocrine Unit, Oxford Centre for Diabetes, Endocrinology & Metabolism (OCDEM), Churchill Hospital, University of Oxford, Oxford, United Kingdom
- National Institute for Health Research Oxford Biomedical Research Centre, Oxford, United Kingdom
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20
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Viering D, Schlingmann KP, Hureaux M, Nijenhuis T, Mallett A, Chan MM, van Beek A, van Eerde AM, Coulibaly JM, Vallet M, Decramer S, Pelletier S, Klaus G, Kömhoff M, Beetz R, Patel C, Shenoy M, Steenbergen EJ, Anderson G, Bongers EM, Bergmann C, Panneman D, Rodenburg RJ, Kleta R, Houillier P, Konrad M, Vargas-Poussou R, Knoers NV, Bockenhauer D, de Baaij JH. Gitelman-Like Syndrome Caused by Pathogenic Variants in mtDNA. J Am Soc Nephrol 2022; 33:305-325. [PMID: 34607911 PMCID: PMC8819995 DOI: 10.1681/asn.2021050596] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 09/06/2021] [Indexed: 02/03/2023] Open
Abstract
BACKGROUND Gitelman syndrome is the most frequent hereditary salt-losing tubulopathy characterized by hypokalemic alkalosis and hypomagnesemia. Gitelman syndrome is caused by biallelic pathogenic variants in SLC12A3, encoding the Na+-Cl- cotransporter (NCC) expressed in the distal convoluted tubule. Pathogenic variants of CLCNKB, HNF1B, FXYD2, or KCNJ10 may result in the same renal phenotype of Gitelman syndrome, as they can lead to reduced NCC activity. For approximately 10 percent of patients with a Gitelman syndrome phenotype, the genotype is unknown. METHODS We identified mitochondrial DNA (mtDNA) variants in three families with Gitelman-like electrolyte abnormalities, then investigated 156 families for variants in MT-TI and MT-TF, which encode the transfer RNAs for phenylalanine and isoleucine. Mitochondrial respiratory chain function was assessed in patient fibroblasts. Mitochondrial dysfunction was induced in NCC-expressing HEK293 cells to assess the effect on thiazide-sensitive 22Na+ transport. RESULTS Genetic investigations revealed four mtDNA variants in 13 families: m.591C>T (n=7), m.616T>C (n=1), m.643A>G (n=1) (all in MT-TF), and m.4291T>C (n=4, in MT-TI). Variants were near homoplasmic in affected individuals. All variants were classified as pathogenic, except for m.643A>G, which was classified as a variant of uncertain significance. Importantly, affected members of six families with an MT-TF variant additionally suffered from progressive chronic kidney disease. Dysfunction of oxidative phosphorylation complex IV and reduced maximal mitochondrial respiratory capacity were found in patient fibroblasts. In vitro pharmacological inhibition of complex IV, mimicking the effect of the mtDNA variants, inhibited NCC phosphorylation and NCC-mediated sodium uptake. CONCLUSION Pathogenic mtDNA variants in MT-TF and MT-TI can cause a Gitelman-like syndrome. Genetic investigation of mtDNA should be considered in patients with unexplained Gitelman syndrome-like tubulopathies.
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Affiliation(s)
- Daan Viering
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Karl P. Schlingmann
- Department of General Pediatrics, University Children’s Hospital, Münster, Germany
| | - Marguerite Hureaux
- Reference Center for Hereditary Kidney and Childhood Diseases (Maladies rénales héréditaires de l'enfant et de l'adulte [MARHEA]), Paris, France,Department of Genetics, Assistance Publique Hôpitaux de Paris, Hôpital Européen Georges-Pompidou, Paris, France
| | - Tom Nijenhuis
- Department of Nephrology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Andrew Mallett
- Department of Renal Medicine, Townsville University Hospital, Townsville, Australia,Queensland Conjoint Renal Genetics Service – Genetic Health Queensland, Royal Brisbane and Women’s Hospital, Brisbane, Australia
| | - Melanie M.Y. Chan
- Department of Renal Medicine, University College London, London, United Kingdom
| | - André van Beek
- Department of Endocrinology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | | | | | - Marion Vallet
- Department of Physiological Functional Investigations, Centre Hospitalier Universitaire de Toulouse, Université Paul Sabatier, Toulouse, France
| | - Stéphane Decramer
- Pediatric Nephrology, Internal Medicine and Rheumatology, Southwest Renal Rare Diseases Centre (SORARE), University Children's Hospital, Toulouse, France
| | - Solenne Pelletier
- Department of Nephrology, University Hospital–Lyon Sud, Lyon, France
| | - Günter Klaus
- Kuratorium für Heimdialyse Pediatric Kidney Center, Marburg, Germany
| | - Martin Kömhoff
- University Children's Hospital, Philipps-University, Marburg, Germany
| | - Rolf Beetz
- Johannes Gutenberg Universität Mainz, Zentrum für Kinder- und Jugendmedizin, Mainz, Germany
| | - Chirag Patel
- Queensland Conjoint Renal Genetics Service – Genetic Health Queensland, Royal Brisbane and Women’s Hospital, Brisbane, Australia
| | - Mohan Shenoy
- Department of Paediatric Nephrology, Royal Manchester Children’s Hospital, Manchester, United Kingdom
| | - Eric J. Steenbergen
- Department of Pathology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Glenn Anderson
- Department of Pathology, Great Ormond Street Hospital for Children National Health Service (NHS) Foundation Trust, London, United Kingdom
| | - Ernie M.H.F. Bongers
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Carsten Bergmann
- Limbach Genetics, Medizinische Genetik Mainz, Prof. Bergmann & Kollegen, Mainz, Germany,Department of Medicine, Division of Nephrology, University Hospital Freiburg, Germany
| | - Daan Panneman
- Radboud Center for Mitochondrial Medicine, Translational Metabolic Laboratory, Department of Pediatrics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Richard J. Rodenburg
- Radboud Center for Mitochondrial Medicine, Translational Metabolic Laboratory, Department of Pediatrics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Robert Kleta
- Department of Renal Medicine, University College London, London, United Kingdom,Department of Paediatric Nephrology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, United Kingdom
| | - Pascal Houillier
- Reference Center for Hereditary Kidney and Childhood Diseases (Maladies rénales héréditaires de l'enfant et de l'adulte [MARHEA]), Paris, France,Centre de Recherche des Cordeliers, Sorbonne Université, Institut National de la Santé et de Recherche Médicale (INSERM), Université de Paris, Centre National de la Recherche Scientifique (CNRS), Paris, France,Department of Physiology, Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Paris, France
| | - Martin Konrad
- Department of General Pediatrics, University Children’s Hospital, Münster, Germany
| | - Rosa Vargas-Poussou
- Reference Center for Hereditary Kidney and Childhood Diseases (Maladies rénales héréditaires de l'enfant et de l'adulte [MARHEA]), Paris, France,Department of Genetics, Assistance Publique Hôpitaux de Paris, Hôpital Européen Georges-Pompidou, Paris, France,Centre de Recherche des Cordeliers, Sorbonne Université, Institut National de la Santé et de Recherche Médicale (INSERM), Université de Paris, Centre National de la Recherche Scientifique (CNRS), Paris, France
| | - Nine V.A.M. Knoers
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Detlef Bockenhauer
- Department of Renal Medicine, University College London, London, United Kingdom,Renal Unit, Great Ormond Street Hospital for Children NHS Foundation Trust, London, United Kingdom
| | - Jeroen H.F. de Baaij
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
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21
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Florea L, Caba L, Gorduza EV. Genetic Heterogeneity in Bartter Syndrome: Clinical and Practical Importance. Front Pediatr 2022; 10:908655. [PMID: 35722471 PMCID: PMC9203713 DOI: 10.3389/fped.2022.908655] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 04/21/2022] [Indexed: 11/13/2022] Open
Abstract
Bartter syndrome (BS) is a rare tubulopathy that causes polyuria, hypokalemia, hypochloremic metabolic alkalosis, and normotensive hyperreninemic hyperaldosteronism. It is characterized by locus, clinical, and allelic heterogeneity. Types 1-4 of BS are inherited according to an autosomal recessive pattern, while type 5, which is transient, is X linked. There are specific correlations between the clinical expression and the molecular defect, but since it is a rare disease, such studies are rare. Therapeutic interventions are different, being correlated with types of BS.
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Affiliation(s)
- Laura Florea
- Department of Nephrology-Internal Medicine, Faculty of Medicine, "Grigore T. Popa" University of Medicine and Pharmacy, Iasi, Romania
| | - Lavinia Caba
- Department of Medical Genetics, Faculty of Medicine, "Grigore T. Popa" University of Medicine and Pharmacy, Iasi, Romania
| | - Eusebiu Vlad Gorduza
- Department of Medical Genetics, Faculty of Medicine, "Grigore T. Popa" University of Medicine and Pharmacy, Iasi, Romania
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22
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Kouyoumdzian NM, Kim G, Rudi MJ, Rukavina Mikusic NL, Fernández BE, Choi MR. Clues and new evidences in arterial hypertension: unmasking the role of the chloride anion. Pflugers Arch 2021; 474:155-176. [PMID: 34966955 DOI: 10.1007/s00424-021-02649-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2021] [Revised: 12/02/2021] [Accepted: 12/03/2021] [Indexed: 02/06/2023]
Abstract
The present review will focus on the role of chloride anion in cardiovascular disease, with special emphasis in the development of hypertensive disease and vascular inflammation. It is known that acute and chronic overload of sodium chloride increase blood pressure and have pro-inflammatory and pro-fibrotic effects on different target organs, but it is unknown how chloride may influence these processes. Chloride anion is the predominant anion in the extracellular fluid and its intracellular concentration is dynamically regulated. As the queen of the electrolytes, it is of crucial importance to understand the physiological mechanisms that regulate the cellular handling of this anion including the different transporters and cellular chloride channels, which exert a variety of functions, such as regulation of cellular proliferation, differentiation, migration, apoptosis, intracellular pH and cellular redox state. In this article, we will also review the relationship between dietary, serum and intracellular chloride and how these different sources of chloride in the organism are affected in hypertension and their impact on cardiovascular disease. Additionally, we will discuss the approach of potential strategies that affect chloride handling and its potential effect on cardiovascular system, including pharmacological blockade of chloride channels and non-pharmacological interventions by replacing chloride by another anion.
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Affiliation(s)
- Nicolás Martín Kouyoumdzian
- Universidad de Buenos Aires, CONICET, Instituto Alberto C. Taquini de Investigaciones en Medicina Traslacional (IATIMET), Buenos Aires, Argentina.
| | - Gabriel Kim
- Facultad de Farmacia Y Bioquímica, Departamento de Ciencias Biológicas, Cátedra de Anatomía e Histología, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - María Julieta Rudi
- Facultad de Farmacia Y Bioquímica, Departamento de Ciencias Biológicas, Cátedra de Anatomía e Histología, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Natalia Lucía Rukavina Mikusic
- Facultad de Farmacia Y Bioquímica, Departamento de Ciencias Biológicas, Cátedra de Anatomía e Histología, Universidad de Buenos Aires, Buenos Aires, Argentina
| | | | - Marcelo Roberto Choi
- Universidad de Buenos Aires, CONICET, Instituto Alberto C. Taquini de Investigaciones en Medicina Traslacional (IATIMET), Buenos Aires, Argentina.,Facultad de Farmacia Y Bioquímica, Departamento de Ciencias Biológicas, Cátedra de Anatomía e Histología, Universidad de Buenos Aires, Buenos Aires, Argentina.,Instituto Universitario de Ciencias de La Salud, Fundación H.A. Barceló, Buenos Aires, Argentina
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23
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Cogal AG, Arroyo J, Shah RJ, Reese KJ, Walton BN, Reynolds LM, Kennedy GN, Seide BM, Senum SR, Baum M, Erickson SB, Jagadeesh S, Soliman NA, Goldfarb DS, Beara-Lasic L, Edvardsson VO, Palsson R, Milliner DS, Sas DJ, Lieske JC, Harris PC. Comprehensive Genetic Analysis Reveals Complexity of Monogenic Urinary Stone Disease. Kidney Int Rep 2021; 6:2862-2884. [PMID: 34805638 PMCID: PMC8589729 DOI: 10.1016/j.ekir.2021.08.033] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 08/24/2021] [Accepted: 08/30/2021] [Indexed: 01/06/2023] Open
Abstract
Introduction Because of phenotypic overlap between monogenic urinary stone diseases (USD), gene-specific analyses can result in missed diagnoses. We used targeted next generation sequencing (tNGS), including known and candidate monogenic USD genes, to analyze suspected primary hyperoxaluria (PH) or Dent disease (DD) patients genetically unresolved (negative; N) after Sanger analysis of the known genes. Cohorts consisted of 285 PH (PHN) and 59 DD (DDN) families. Methods Variants were assessed using disease-specific and population databases plus variant assessment tools and categorized using the American College of Medical Genetics (ACMG) guidelines. Prior Sanger analysis identified 47 novel PH or DD gene pathogenic variants. Results Screening by tNGS revealed pathogenic variants in 14 known monogenic USD genes, accounting for 45 families (13.1%), 27 biallelic and 18 monoallelic, including 1 family with a copy number variant (CNV). Recurrent genes included the following: SLC34A3 (n = 13), CLDN16 (n = 8), CYP24A1 (n = 4), SLC34A1 (n = 3), SLC4A1 (n = 3), APRT (n = 2), CLDN19 (n = 2), HNF4A1 (n = 2), and KCNJ1 (n = 2), whereas ATP6V1B1, CASR, and SLC12A1 and missed CNVs in the PH genes AGXT and GRHPR accounted for 1 pedigree each. Of the 48 defined pathogenic variants, 27.1% were truncating and 39.6% were novel. Most patients were diagnosed before 18 years of age (76.1%), and 70.3% of biallelic patients were homozygous, mainly from consanguineous families. Conclusion Overall, in patients suspected of DD or PH, 23.9% and 7.3% of cases, respectively, were caused by pathogenic variants in other genes. This study shows the value of a tNGS screening approach to increase the diagnosis of monogenic USD, which can optimize therapies and facilitate enrollment in clinical trials.
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Affiliation(s)
- Andrea G Cogal
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA
| | - Jennifer Arroyo
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA
| | - Ronak Jagdeep Shah
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA
| | - Kalina J Reese
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota, USA
| | - Brenna N Walton
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota, USA
| | - Laura M Reynolds
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota, USA
| | - Gabrielle N Kennedy
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota, USA
| | - Barbara M Seide
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA
| | - Sarah R Senum
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA
| | | | - Stephen B Erickson
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA
| | | | - Neveen A Soliman
- Department of Pediatrics, Center of Pediatric Nephrology and Transplantation, Kasr Al Ainy School of Medicine, Cairo University, Cairo, Egypt
| | - David S Goldfarb
- Nephrology Division, New York University Langone Health and New York University School of Medicine, New York, New York, USA
| | - Lada Beara-Lasic
- Nephrology Division, New York University Langone Health and New York University School of Medicine, New York, New York, USA
| | - Vidar O Edvardsson
- Faculty of Medicine, School of Health Sciences, University of Iceland, Reykjavik, Iceland.,Children's Medical Center, Landspitali-The National University Hospital of Iceland, Reykjavik, Iceland
| | - Runolfur Palsson
- Faculty of Medicine, School of Health Sciences, University of Iceland, Reykjavik, Iceland.,Division of Nephrology, Landspitali-The National University Hospital of Iceland, Reykjavik, Iceland
| | - Dawn S Milliner
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA
| | - David J Sas
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA.,Division of Pediatric Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA.,Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA
| | - John C Lieske
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA.,Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA
| | - Peter C Harris
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA.,Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota, USA
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24
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Claverie-Martin F, Perdomo-Ramirez A, Garcia-Nieto V. Hereditary kidney diseases associated with hypomagnesemia. Kidney Res Clin Pract 2021; 40:512-526. [PMID: 34784661 PMCID: PMC8685365 DOI: 10.23876/j.krcp.21.112] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 06/20/2021] [Indexed: 11/04/2022] Open
Abstract
In the kidney, a set of proteins expressed in the epithelial cells of the thick ascending loop of Henle and the distal convoluted tubule directly or indirectly play important roles in the regulation of serum magnesium levels. Magnesium reabsorption in the thick ascending loop of Henle occurs through a passive paracellular pathway, while in the distal convoluted tubule, the final magnesium concentration is established through an active transcellular pathway. The players involved in magnesium reabsorption include proteins with diverse functions including tight junction proteins, cation and anion channels, sodium chloride cotransporter, calcium-sensing receptor, epidermal growth factor, cyclin M2, sodium potassium adenosine triphosphatase subunits, transcription factors, a serine protease, and proteins involved in mitochondrial function. Mutations in the genes that encode these proteins impair their function and cause different rare diseases associated with hypomagnesemia, which may lead to muscle cramps, fatigue, epileptic seizures, intellectual disability, cardiac arrhythmias, and chronic kidney disease. The purpose of this review is to describe the clinical and genetic characteristics of these hereditary kidney diseases and the current research findings on the pathophysiological basis of these diseases.
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Affiliation(s)
- Felix Claverie-Martin
- Unidad de Investigación, Hospital Universitario Nuestra Señora de Candelaria, Santa Cruz de Tenerife, Spain
| | - Ana Perdomo-Ramirez
- Unidad de Investigación, Hospital Universitario Nuestra Señora de Candelaria, Santa Cruz de Tenerife, Spain
| | - Victor Garcia-Nieto
- Unidad de Nefrología Pediátrica, Hospital Universitario Nuestra Señora de Candelaria, Santa Cruz de Tenerife, Spain
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25
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Accurate interpretation of genetic variants in sudden unexpected death in infancy by trio-targeted gene-sequencing panel analysis. Sci Rep 2021; 11:21532. [PMID: 34728707 PMCID: PMC8563990 DOI: 10.1038/s41598-021-00962-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 10/20/2021] [Indexed: 12/18/2022] Open
Abstract
In sudden unexpected death in infancy cases, postmortem genetic analysis with next-generation sequencing potentially can extract candidate genes associated with sudden death. However, it is difficult to accurately interpret the clinically significant genetic variants. The study aim was to conduct trio analysis of cases of sudden unexpected death in infancy and their parents to more accurately interpret the clinically significant disease-associated gene variants associated with cause of death. From the TruSight One panel targeting 4813 genes we extracted candidate genetic variants of 66 arrhythmia-, 63 inherited metabolic disease-, 81 mitochondrial disease-, and 6 salt-losing tubulopathy-related genes in 7 cases and determined if they were de novo or parental-derived variants. Thirty-four parental-derived variants and no de novo variants were found, but none appeared to be related to the cause of death. Using trio analysis and an in silico algorithm to analyze all 4813 genes, we identified OBSCN of compound heterozygous and HCCS of hemizygous variants as new candidate genetic variants related to cause of death. Genetic analysis of these deceased infants and their living parents can provide more accurate interpretation of the clinically significant genetic variants than previously possible and help confirm the cause of death.
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26
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Ham Y, Mack H, Colville D, Harraka P, Savige J. Gitelman syndrome and ectopic calcification in the retina and joints. Clin Kidney J 2021; 14:2023-2028. [PMID: 34476088 PMCID: PMC8406063 DOI: 10.1093/ckj/sfab034] [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: 09/19/2020] [Indexed: 11/23/2022] Open
Abstract
Gitelman syndrome is a rare inherited renal tubular disorder with features that resemble thiazide use, including a hypokalemic metabolic alkalosis, hypomagnesemia, hypocalciuria and a low or normal blood pressure, hyperreninemia and hyperaldosteronism. Treatment is primarily correction of the potassium and magnesium levels. The diagnosis is confirmed with genetic testing but Gitelman syndrome is often not suspected. However, the association with ectopic calcification in the retina, blood vessels and chondrocalcinosis in the joints is a useful pointer to this diagnosis. Bilateral symmetrical whitish deposits of calcium pyrophosphate are visible superotemporally on ophthalmoscopy and retinal photography but are actually located beneath the retina in the sclerochoroid. Optical coherence tomography is even more sensitive for their detection. These deposits increase in size with time, but the rate of progression slows with long-term correction of the hypomagnesemia. Calcification may be complicated by atrophy of the overlying retina and visual loss. The deposits often correlate with ectopic calcification in the aorta and coronary and cerebral vessels. Chondrocalcinosis occurs in the large joints such as the knees. Ectopic calcification in Gitelman syndrome indicates the need for more aggressive management of Mg levels. Calcification is much less common in Bartter syndrome, which itself is rarer and associated less often with hypomagnesemia.
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Affiliation(s)
- Yeji Ham
- Department of Medicine, University of Melbourne, Melbourne Health and Northern Health, Royal Melbourne Hospital, Parkville, VIC, Australia
| | - Heather Mack
- Department of Ophthalmology, University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, VIC, Australia
| | - Deb Colville
- Department of Medicine, University of Melbourne, Melbourne Health and Northern Health, Royal Melbourne Hospital, Parkville, VIC, Australia
| | - Philip Harraka
- Department of Medicine, University of Melbourne, Melbourne Health and Northern Health, Royal Melbourne Hospital, Parkville, VIC, Australia
| | - Judy Savige
- Department of Medicine, University of Melbourne, Melbourne Health and Northern Health, Royal Melbourne Hospital, Parkville, VIC, Australia
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27
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Abstract
Mutations in approximately 80 genes have been implicated as the cause of various genetic kidney diseases. However, gene delivery to kidney cells from the blood is inefficient because of the natural filtering functions of the glomerulus, and research into and development of gene therapy directed toward kidney disease has lagged behind as compared with hepatic, neuromuscular, and ocular gene therapy. This lack of progress is in spite of numerous genetic mouse models of human disease available to the research community and many vectors in existence that can theoretically deliver genes to kidney cells with high efficiency. In the past decade, several groups have begun to develop novel injection techniques in mice, such as retrograde ureter, renal vein, and direct subcapsular injections to help resolve the issue of gene delivery to the kidney through the blood. In addition, the ability to retarget vectors specifically toward kidney cells has been underutilized but shows promise. This review discusses how recent advances in gene delivery to the kidney and the field of gene therapy can leverage the wealth of knowledge of kidney genetics to work toward developing gene therapy products for patients with kidney disease.
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29
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Tan RSG, Lee CHL, Dimke H, Todd Alexander R. The role of calcium-sensing receptor signaling in regulating transepithelial calcium transport. Exp Biol Med (Maywood) 2021; 246:2407-2419. [PMID: 33926258 DOI: 10.1177/15353702211010415] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The calcium-sensing receptor (CaSR) plays a critical role in sensing extracellular calcium (Ca2+) and signaling to maintain Ca2+ homeostasis. In the parathyroid, the CaSR regulates secretion of parathyroid hormone, which functions to increase extracellular Ca2+ levels. The CaSR is also located in other organs imperative to Ca2+ homeostasis including the kidney and intestine, where it modulates Ca2+ reabsorption and absorption, respectively. In this review, we describe CaSR expression and its function in transepithelial Ca2+ transport in the kidney and intestine. Activation of the CaSR leads to G protein dependent and independent signaling cascades. The known CaSR signal transduction pathways involved in modulating paracellular and transcellular epithelial Ca2+ transport are discussed. Mutations in the CaSR cause a range of diseases that manifest in altered serum Ca2+ levels. Gain-of-function mutations in the CaSR result in autosomal dominant hypocalcemia type 1, while loss-of-function mutations cause familial hypocalciuric hypercalcemia. Additionally, the putative serine protease, FAM111A, is discussed as a potential regulator of the CaSR because mutations in FAM111A cause Kenny Caffey syndrome type 2, gracile bone dysplasia, and osteocraniostenosis, diseases that are characterized by hypocalcemia, hypoparathyroidism, and bony abnormalities, i.e. share phenotypic features of autosomal dominant hypocalcemia. Recent work has helped to elucidate the effect of CaSR signaling cascades on downstream proteins involved in Ca2+ transport across renal and intestinal epithelia; however, much remains to be discovered.
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Affiliation(s)
- Rebecca Siu Ga Tan
- Department of Physiology, University of Alberta, Edmonton T6G 1C9, Canada.,Membrane Protein Disease Research Group, University of Alberta, Edmonton T6G 1C9, Canada
| | | | - Henrik Dimke
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense 5000, Denmark.,Department of Nephrology, Odense University Hospital, Odense 5000, Denmark
| | - R Todd Alexander
- Department of Physiology, University of Alberta, Edmonton T6G 1C9, Canada.,Membrane Protein Disease Research Group, University of Alberta, Edmonton T6G 1C9, Canada.,Department of Pediatrics, University of Alberta, Edmonton T6G 1C9, Canada
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30
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Simultaneous Homozygous Mutations in SLC12A3 and CLCNKB in an Inbred Chinese Pedigree. Genes (Basel) 2021; 12:genes12030369. [PMID: 33807568 PMCID: PMC7999423 DOI: 10.3390/genes12030369] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 02/23/2021] [Accepted: 03/01/2021] [Indexed: 11/30/2022] Open
Abstract
Gitelman syndrome (GS) and Bartter syndrome (BS) type III are both rare, recessively inherited salt-losing tubulopathies caused by SLC12A3 and CLCNKB mutations, respectively. We described a 48-year-old male patient with fatigue, carpopedal spasm, arthralgia, hypokalemic alkalosis, mild renal dysfunction, hypomagnesemia, hypocalciuria, hyperuricemia, normotension, hyperreninemia and chondrocalcinosis in knees and Achilles tendons. His parents are first cousin. Genetic analysis revealed simultaneous homozygous mutations in SLC12A3 gene with c.248G>A, p.Arg83Gln and CLCNKB gene with c.1171T>C, p.Trp391Arg. The second younger brother of the proband harbored the same simultaneous mutations in SLC12A3 and CLCNKB and exhibited similar clinical features except normomagnesemia and bilateral kidney stones. The first younger brother of the proband harbored the same homozygous mutations in CLCNKB and exhibited clinical features of hypokalemia, normomagnesemia, hypercalciuria and hyperuricemia. Potassium chloride, spironolactone and potassium magnesium aspartate were prescribed to the proband to correct electrolytic disturbances. Benzbromarone and febuxostat were prescribed to correct hyperuricemia. The dose of potassium magnesium aspartate was subsequently increased to alleviate arthralgia resulting from calcium pyrophosphate deposition disease (CPPD). To the best of our knowledge, we are the first to report an exceptionally rare case in an inbred Chinese pedigree with simultaneous homozygous mutations in SLC12A3 and CLCNKB. GS and BS type III have significant intrafamilial phenotype heterogeneity. When arthralgia is developed in patients with GS and BS, gout and CPPD should both be considered.
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Konrad M, Nijenhuis T, Ariceta G, Bertholet-Thomas A, Calo LA, Capasso G, Emma F, Schlingmann KP, Singh M, Trepiccione F, Walsh SB, Whitton K, Vargas-Poussou R, Bockenhauer D. Diagnosis and management of Bartter syndrome: executive summary of the consensus and recommendations from the European Rare Kidney Disease Reference Network Working Group for Tubular Disorders. Kidney Int 2021; 99:324-335. [PMID: 33509356 DOI: 10.1016/j.kint.2020.10.035] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 09/30/2020] [Accepted: 10/29/2020] [Indexed: 12/13/2022]
Abstract
Bartter syndrome is a rare inherited salt-losing renal tubular disorder characterized by secondary hyperaldosteronism with hypokalemic and hypochloremic metabolic alkalosis and low to normal blood pressure. The primary pathogenic mechanism is defective salt reabsorption predominantly in the thick ascending limb of the loop of Henle. There is significant variability in the clinical expression of the disease, which is genetically heterogenous with 5 different genes described to date. Despite considerable phenotypic overlap, correlations of specific clinical characteristics with the underlying molecular defects have been demonstrated, generating gene-specific phenotypes. As with many other rare disease conditions, there is a paucity of clinical studies that could guide diagnosis and therapeutic interventions. In this expert consensus document, the authors have summarized the currently available knowledge and propose clinical indicators to assess and improve quality of care.
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Affiliation(s)
- Martin Konrad
- Department of General Pediatrics, University Hospital Münster, Münster, Germany.
| | - Tom Nijenhuis
- Department of Nephrology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Gema Ariceta
- Pediatric Nephrology, Hospital Universitari Vall d'Hebron, Universitat Autonoma de Barcelona, Barcelona, Spain
| | | | - Lorenzo A Calo
- Department of Medicine (DIMED), Nephrology, Dialysis, Transplantation, University of Padova, Padua, Italy
| | - Giovambattista Capasso
- Division of Nephrology, Department of Translational Medical Sciences, School of Medicine, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Francesco Emma
- Division of Nephrology, Department of Pediatric Subspecialties, Bambino Gesù Children's Hospital IRCCS, Rome, Italy
| | - Karl P Schlingmann
- Department of General Pediatrics, University Hospital Münster, Münster, Germany
| | - Mandeep Singh
- Fetal Medicine Centre, Southend University Hospital NHS Foundation Trust, Essex, UK
| | - Francesco Trepiccione
- Division of Nephrology, Department of Translational Medical Sciences, School of Medicine, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Stephen B Walsh
- Department of Renal Medicine, University College London, London, United Kingdom
| | | | - Rosa Vargas-Poussou
- Hôpital Européen Georges Pompidou, Assistance Publique Hôpitaux de Paris, Centre d'Investigation Clinique, Paris, France; Centre de Référence des Maladies Rénales Héréditaires de l'Enfant et de l'Adulte, Paris, France
| | - Detlef Bockenhauer
- Department of Renal Medicine, University College London, London, United Kingdom; Department of Pediatric Nephrology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
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32
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Bamgbola OF, Ahmed Y. Differential diagnosis of perinatal Bartter, Bartter and Gitelman syndromes. Clin Kidney J 2020; 14:36-48. [PMID: 33564404 PMCID: PMC7857843 DOI: 10.1093/ckj/sfaa172] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 06/29/2020] [Indexed: 12/20/2022] Open
Abstract
The common finding of hypokalemic alkalosis in several unrelated disorders may confound the early diagnosis of salt-losing tubulopathy (SLT). Antenatal Bartter syndrome (BS) must be considered in idiopathic early-onset polyhydramnios. Fetal megabladder in BS may allow its distinction from third-trimester polyhydramnios that occurs in congenital chloride diarrhea (CCD). Fetal megacolon occurs in CCD while fecal chloride >90 mEq/L in infants is diagnostic. Failure-to-thrive, polydipsia and polyuria in early childhood are the hallmarks of classic BS. Unlike BS, there is low urinary chloride in hypokalemic alkalosis of intractable emesis and cystic fibrosis. Rarely, renal salt wasting may result from cystinosis, Dent disease, disorders of paracellular claudin-10b and Kir4.1 potassium-channel deficiency. Acquired BS may result from calcimimetic up-regulation of a calcium-sensing receptor or autoantibody inactivation of sodium chloride co-transporters in Sjögren syndrome. A relatively common event of heterozygous gene mutations for Gitelman syndrome increases the likelihood of its random occurrence in certain diseases of adult onset. Finally, diuretic abuse is the most common differential diagnosis of SLT. Unlike the persistent elevation in BS, urinary chloride concentration losses waxes and wanes on day-to-day assessment in patients with diuretic misuse.
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Affiliation(s)
- Oluwatoyin Fatai Bamgbola
- Department of Pediatrics, Division of Pediatric Nephrology, SUNY Downstate Medical Center, Brooklyn, NY, USA
| | - Youssef Ahmed
- Department of Pediatrics, Kings County Hospital, Brooklyn, NY, USA
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Murillo-de-Ozores AR, Chávez-Canales M, de Los Heros P, Gamba G, Castañeda-Bueno M. Physiological Processes Modulated by the Chloride-Sensitive WNK-SPAK/OSR1 Kinase Signaling Pathway and the Cation-Coupled Chloride Cotransporters. Front Physiol 2020; 11:585907. [PMID: 33192599 PMCID: PMC7606576 DOI: 10.3389/fphys.2020.585907] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 09/29/2020] [Indexed: 12/15/2022] Open
Abstract
The role of Cl– as an intracellular signaling ion has been increasingly recognized in recent years. One of the currently best described roles of Cl– in signaling is the modulation of the With-No-Lysine (K) (WNK) – STE20-Proline Alanine rich Kinase (SPAK)/Oxidative Stress Responsive Kinase 1 (OSR1) – Cation-Coupled Cl–Cotransporters (CCCs) cascade. Binding of a Cl– anion to the active site of WNK kinases directly modulates their activity, promoting their inhibition. WNK activation due to Cl– release from the binding site leads to phosphorylation and activation of SPAK/OSR1, which in turn phosphorylate the CCCs. Phosphorylation by WNKs-SPAK/OSR1 of the Na+-driven CCCs (mediating ions influx) promote their activation, whereas that of the K+-driven CCCs (mediating ions efflux) promote their inhibition. This results in net Cl– influx and feedback inhibition of WNK kinases. A wide variety of alterations to this pathway have been recognized as the cause of several human diseases, with manifestations in different systems. The understanding of WNK kinases as Cl– sensitive proteins has allowed us to better understand the mechanistic details of regulatory processes involved in diverse physiological phenomena that are reviewed here. These include cell volume regulation, potassium sensing and intracellular signaling in the renal distal convoluted tubule, and regulation of the neuronal response to the neurotransmitter GABA.
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Affiliation(s)
- Adrián Rafael Murillo-de-Ozores
- Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico.,Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - María Chávez-Canales
- Unidad de Investigación UNAM-INC, Instituto Nacional de Cardiología Ignacio Chávez and Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Paola de Los Heros
- Unidad de Investigación UNAM-INC, Research Division, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Gerardo Gamba
- Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico.,Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - María Castañeda-Bueno
- Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
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Radonsky V, Kizys MML, Dotto RP, Esper PLG, Heilberg IP, Dias-da-Silva MR, Lazaretti-Castro M. Hypomagnesemia with Hypercalciuria Leading to Nephrocalcinosis, Amelogenesis Imperfecta, and Short Stature in a Child Carrying a Homozygous Deletion in the CLDN16 Gene. Calcif Tissue Int 2020; 107:403-408. [PMID: 32710267 DOI: 10.1007/s00223-020-00726-y] [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: 05/14/2020] [Accepted: 07/08/2020] [Indexed: 10/23/2022]
Abstract
Familial hypomagnesemia with hypercalciuria and nephrocalcinosis (FHHNC) is a rare autosomal recessive disease caused by mutations in the CLDN16 or CLDN19 gene; however, few cases develop classical amelogenesis imperfecta. Herein, we report the case of a boy with early clinical renal manifestations that started at 1 year of age and presenting with dental hypoplasia and growth delay. The patient presented with vomiting, polyuria, and polydipsia. Apart from recurrent sterile leukocyturia, erroneously treated as infectious, he was normal, except for short stature and amelogenesis imperfecta with gradually discolored teeth. Laboratory tests revealed hyperparathyroidism, hypomagnesemia, severe hypercalciuria, and hypermagnesuria on 24-h urine testing. Helical computed tomography confirmed nephrocalcinosis. We performed whole-exome sequencing (WES) to test the hypothesis of FHHNC and oligogenic inheritance of amelogenesis. Analysis of the WES binary sequence alignment/map file revealed the presence of exon 1 of the CLDN16 and absence of the other exons [c.325_c918*? (E2_E5del)]. We confirmed a CLDN16 E2_E5 homozygous deletion by multiplex ligation-dependent probe amplification and polymerase chain reaction assays. Although most mutations causing FHHNC are missense and nonsense mutations in the CLDN16 or CLDN19 gene, large deletions occur and may be misled by WES, which is generally used for genetic screening of oligogenic disorders. The patient received cholecalciferol, magnesium oxide and potassium citrate. Later, the combination with hydrochlorothiazide plus amiloride was prescribed, with a good response during follow-up. Our report broadens the phenotype of FHHNC, including severe early-onset amelogenesis and short stature, and reinforces the phenotype-genotype correlation of the large deletion found in CLDN16.
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Affiliation(s)
- Vanessa Radonsky
- Division of Endocrinology, Escola Paulista de Medicina, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
| | - Marina Malta Letro Kizys
- Division of Endocrinology, Escola Paulista de Medicina, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
| | - Renata Pires Dotto
- Division of Endocrinology, Escola Paulista de Medicina, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
| | - Priscila Ligeiro Gonçalves Esper
- Division of Nephrology, Department of Medicine, Escola Paulista de Medicina, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
| | - Ita Pfeferman Heilberg
- Division of Nephrology, Department of Medicine, Escola Paulista de Medicina, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
| | - Magnus Regios Dias-da-Silva
- Division of Endocrinology, Escola Paulista de Medicina, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil.
- Laboratory of Molecular and Translational Endocrinology, Division of Endocrinology, Department of Medicine, Escola Paulista de Medicina, Universidade Federal de São Paulo, Rua Pedro de Toledo, 669, 11° andar, São Paulo, SP, 04039-032, Brazil.
| | - Marise Lazaretti-Castro
- Division of Endocrinology, Escola Paulista de Medicina, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
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35
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Wu X, Yang G, Chen S, Tang M, Jian S, Chen F, Wu X. Bartter syndrome with long-term follow-up: a case report. J Int Med Res 2020; 48:300060520947876. [PMID: 32857947 PMCID: PMC7705384 DOI: 10.1177/0300060520947876] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Bartter syndrome is a rare inherited disease caused by CLCNKB mutation, which results in inactivation of the chloride channel Kb protein. Bartter syndrome is characterized by extreme hypokalemia, hypochloremia, metabolic alkalosis, hyperrenin-induced angiotensinemia, hyperaldosteronemia, and normal blood pressure. We herein report a case of Bartter syndrome that manifested as vomiting, hypokalemia, metabolic alkalosis, normal blood pressure, and significant hyperrenin-induced angiotensinemia. The patient, a 5-month-old girl, carried two known heterozygous pathogenic mutations: c.88C > T (p.Arg30*), which she had inherited from her father, and c.1313G > A (p.Arg438His), which she had inherited from her mother. Treatment with indomethacin, a nonsteroidal anti-inflammatory drug, led to rapid improvement of the hypokalemia, and treatment was continued for 14 years. The indomethacin also induced a sustainable reduction in the hypokalemia and metabolic alkalosis.
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Affiliation(s)
- Xueling Wu
- Department of Respiratory Medicine, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China
| | - Gang Yang
- Department of Cardiology, the Second Affiliated Hospital of Chongqing Medical University, Chongqing, Sichuan, China
| | - Shiyu Chen
- Key Laboratory of Diagnostic Medicine designated by the Chinese Ministry of Education, Chongqing Medical University, Chongqing, Sichuan, China
| | - Min Tang
- Key Laboratory of Diagnostic Medicine designated by the Chinese Ministry of Education, Chongqing Medical University, Chongqing, Sichuan, China
| | - Shan Jian
- Department of Paediatrics, Peking Union Medical College Hospital, Beijing, China
| | - Fuhui Chen
- Department of Respiratory, the Second Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China
| | - Xiulin Wu
- Department of Geriatrics, Southwest Hospital, Military Medical University, Chongqing, China
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36
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Chavan TS, Cheng RC, Jiang T, Mathews II, Stein RA, Koehl A, Mchaourab HS, Tajkhorshid E, Maduke M. A CLC-ec1 mutant reveals global conformational change and suggests a unifying mechanism for the CLC Cl -/H + transport cycle. eLife 2020; 9:53479. [PMID: 32310757 PMCID: PMC7253180 DOI: 10.7554/elife.53479] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2019] [Accepted: 04/18/2020] [Indexed: 12/16/2022] Open
Abstract
Among coupled exchangers, CLCs uniquely catalyze the exchange of oppositely charged ions (Cl– for H+). Transport-cycle models to describe and explain this unusual mechanism have been proposed based on known CLC structures. While the proposed models harmonize with many experimental findings, gaps and inconsistencies in our understanding have remained. One limitation has been that global conformational change – which occurs in all conventional transporter mechanisms – has not been observed in any high-resolution structure. Here, we describe the 2.6 Å structure of a CLC mutant designed to mimic the fully H+-loaded transporter. This structure reveals a global conformational change to improve accessibility for the Cl– substrate from the extracellular side and new conformations for two key glutamate residues. Together with DEER measurements, MD simulations, and functional studies, this new structure provides evidence for a unified model of H+/Cl– transport that reconciles existing data on all CLC-type proteins. Cells are shielded from harmful molecules and other threats by a thin, flexible layer called the membrane. However, this barrier also prevents chloride, sodium, protons and other ions from moving in or out of the cell. Channels and transporters are two types of membrane proteins that form passageways for these charged particles. Channels let ions flow freely from one side of the membrane to the other. To do so, these proteins change their three-dimensional shape to open or close as needed. On the other hand, transporters actively pump ions across the membrane to allow the charged particles to accumulate on one side. The shape changes needed for that type of movement are different: the transporters have to open a passageway on one side of the membrane while closing it on the other side, alternating openings to one side or the other. In general, channels and transporters are not related to each other, but one exception is a group called CLCs proteins. Present in many organisms, this family contains a mixture of channels and transporters. For example, humans have nine CLC proteins: four are channels that allow chloride ions in and out, and five are ‘exchange transporters’ that make protons and chloride ions cross the membrane in opposite directions. These proteins let one type of charged particle move freely across the membrane, which generates energy that the transporter then uses to actively pump the other ion in the direction needed by the cell. Yet, the exact three-dimensional changes required for CLC transporters and channels to perform their roles are still unknown. To investigate this question, Chavan, Cheng et al. harnessed a technique called X-ray crystallography, which allows scientists to look at biological molecules at the level of the atom. This was paired with other methods to examine a CLC mutant that adopts the shape of a normal CLC transporter when it is loaded with a proton. The experiments revealed how various elements in the transporter move relative to each other to adopt a structure that allows protons and chloride ions to enter the protein from opposite sides of the membrane, using separate pathways. While obtained on a bacterial CLC, these results can be applied to other CLC channels and transporters (including those in humans), shedding light on how this family transports charged particles across membranes. From bone diseases to certain types of seizures, many human conditions are associated with poorly functioning CLCs. Understanding the way these structures change their shapes to perform their roles could help to design new therapies for these health problems.
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Affiliation(s)
- Tanmay S Chavan
- Department of Molecular & Cellular Physiology, Stanford University School of Medicine, Stanford, United States
| | - Ricky C Cheng
- Department of Molecular & Cellular Physiology, Stanford University School of Medicine, Stanford, United States
| | - Tao Jiang
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, United States
| | - Irimpan I Mathews
- Stanford Synchrotron Radiation Lightsource, Stanford University, Menlo Park, United States
| | - Richard A Stein
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, United States
| | - Antoine Koehl
- Department of Molecular & Cellular Physiology, Stanford University School of Medicine, Stanford, United States
| | - Hassane S Mchaourab
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, United States
| | - Emad Tajkhorshid
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, United States
| | - Merritt Maduke
- Department of Molecular & Cellular Physiology, Stanford University School of Medicine, Stanford, United States
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37
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Sahbani D, Strumbo B, Tedeschi S, Conte E, Camerino GM, Benetti E, Montini G, Aceto G, Procino G, Imbrici P, Liantonio A. Functional Study of Novel Bartter's Syndrome Mutations in ClC-Kb and Rescue by the Accessory Subunit Barttin Toward Personalized Medicine. Front Pharmacol 2020; 11:327. [PMID: 32256370 PMCID: PMC7092721 DOI: 10.3389/fphar.2020.00327] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 03/05/2020] [Indexed: 12/12/2022] Open
Abstract
Type III and IV Bartter syndromes (BS) are rare kidney tubulopathies caused by loss-of-function mutations in the CLCNKB and BSND genes coding respectively for the ClC-Kb chloride channels and accessory subunit barttin. ClC-K channels are expressed in the Henle's loop, distal convoluted tubule, and cortical collecting ducts of the kidney and contribute to chloride absorption and urine concentration. In our Italian cohort, we identified two new mutations in CLCNKB, G167V and G289R, in children affected by BS and previously reported genetic variants, A242E, a chimeric gene and the deletion of the whole CLCNKB. All the patients had hypokalemia and metabolic alkalosis, increased serum renin and aldosterone levels and were treated with a symptomatic therapy. In order to define the molecular mechanisms responsible for BS, we co-expressed ClC-Kb wild type and channels with point mutations with barttin in HEK 293 cells and characterized chloride currents through the patch-clamp technique. In addition, we attempted to revert the functional defect caused by BS mutations through barttin overexpression. G167V and A242E channels showed a drastic current reduction compared to wild type, likely suggesting compromised expression of mutant channels at the plasma membrane. Conversely, G289R channel was similar to wild type raising the doubt that an additional mutation in another gene or other mechanisms could account for the clinical phenotype. Interestingly, increasing ClC-K/barttin ratio augmented G167V and A242E mutants' chloride current amplitudes towards wild type levels. These results confirm a genotype-phenotype correlation in BS and represent a preliminary proof of concept that molecules functioning as molecular chaperones can restore channel function in expression-defective ClC-Kb mutants.
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Affiliation(s)
- Dalila Sahbani
- Department of Pharmacy-Drug Sciences, University of Bari "Aldo Moro", Bari, Italy
| | - Bice Strumbo
- Laboratory of Medical Genetics, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Silvana Tedeschi
- Laboratory of Medical Genetics, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Elena Conte
- Department of Pharmacy-Drug Sciences, University of Bari "Aldo Moro", Bari, Italy
| | | | - Elisa Benetti
- Nephrology, Dialysis and Transplant Unit, Department of Women's and Children's Health, University-Hospital of Padova, Padova, Italy
| | - Giovanni Montini
- Pediatric Nephrology, Dialysis, and Transplant Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.,Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | | | - Giuseppe Procino
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari "Aldo Moro", Bari, Italy
| | - Paola Imbrici
- Department of Pharmacy-Drug Sciences, University of Bari "Aldo Moro", Bari, Italy
| | - Antonella Liantonio
- Department of Pharmacy-Drug Sciences, University of Bari "Aldo Moro", Bari, Italy
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38
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Iancu D, Ashton E. Inherited Renal Tubulopathies-Challenges and Controversies. Genes (Basel) 2020; 11:genes11030277. [PMID: 32150856 PMCID: PMC7140864 DOI: 10.3390/genes11030277] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 02/29/2020] [Accepted: 02/29/2020] [Indexed: 12/23/2022] Open
Abstract
Electrolyte homeostasis is maintained by the kidney through a complex transport function mostly performed by specialized proteins distributed along the renal tubules. Pathogenic variants in the genes encoding these proteins impair this function and have consequences on the whole organism. Establishing a genetic diagnosis in patients with renal tubular dysfunction is a challenging task given the genetic and phenotypic heterogeneity, functional characteristics of the genes involved and the number of yet unknown causes. Part of these difficulties can be overcome by gathering large patient cohorts and applying high-throughput sequencing techniques combined with experimental work to prove functional impact. This approach has led to the identification of a number of genes but also generated controversies about proper interpretation of variants. In this article, we will highlight these challenges and controversies.
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Affiliation(s)
- Daniela Iancu
- UCL-Centre for Nephrology, Royal Free Campus, University College London, Rowland Hill Street, London NW3 2PF, UK
- Correspondence: ; Tel.: +44-2381204172; Fax: +44-020-74726476
| | - Emma Ashton
- Rare & Inherited Disease Laboratory, London North Genomic Laboratory Hub, Great Ormond Street Hospital for Children National Health Service Foundation Trust, Levels 4-6 Barclay House 37, Queen Square, London WC1N 3BH, UK;
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39
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Besouw MTP, Kleta R, Bockenhauer D. Bartter and Gitelman syndromes: Questions of class. Pediatr Nephrol 2020; 35:1815-1824. [PMID: 31664557 PMCID: PMC7501116 DOI: 10.1007/s00467-019-04371-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 08/28/2019] [Accepted: 09/17/2019] [Indexed: 12/30/2022]
Abstract
Bartter and Gitelman syndromes are rare inherited tubulopathies characterized by hypokalaemic, hypochloraemic metabolic alkalosis. They are caused by mutations in at least 7 genes involved in the reabsorption of sodium in the thick ascending limb (TAL) of the loop of Henle and/or the distal convoluted tubule (DCT). Different subtypes can be distinguished and various classifications have been proposed based on clinical symptoms and/or the underlying genetic cause. Yet, the clinical phenotype can show remarkable variability, leading to potential divergences between classifications. These problems mostly relate to uncertainties over the role of the basolateral chloride exit channel CLCNKB, expressed in both TAL and DCT and to what degree the closely related paralogue CLCNKA can compensate for the loss of CLCNKB function. Here, we review what is known about the physiology of the transport proteins involved in these disorders. We also review the various proposed classifications and explain why a gene-based classification constitutes a pragmatic solution.
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Affiliation(s)
- Martine T. P. Besouw
- Department of Pediatric Nephrology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Robert Kleta
- Renal Unit, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK ,Department of Renal Medicine, University College London, London, UK
| | - Detlef Bockenhauer
- Renal Unit, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK ,Department of Renal Medicine, University College London, London, UK
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40
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Thakore P, Anderson M, Yosypiv IV. Classic Bartter Syndrome: A Cause of Severe Hypokalemic Metabolic Alkalosis. Clin Pediatr (Phila) 2019; 58:1557-1561. [PMID: 31230456 DOI: 10.1177/0009922819857535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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41
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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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Deng Z, Li W, Alahdal M, Zhang N, Xie J, Hu X, Chen Y, Fang H, Duan L, Gu L, Wang D. Overexpression of ClC-3 Chloride Channel in Chondrosarcoma: An In Vivo Immunohistochemical Study with Tissue Microarray. Med Sci Monit 2019; 25:5044-5053. [PMID: 31281178 PMCID: PMC6637820 DOI: 10.12659/msm.917382] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Background Recently, ClC-3 chloride channel expression has been noted to be high in some tumors. In chondrosarcoma, which is a malignant tumor with a high incidence in the bone, there has been no previous literature regarding ClC-3 chloride channel expression. Here we evaluated the expression of ClC-3 chloride channel in chondrosarcoma and explored its clinical significance. Material/Methods In this study, 75 chondrosarcoma and 5 normal cartilage tissues were collected. Thereafter, tissue microarray was performed. Immunohistochemistry was also used to observe the level of ClC-3 chloride channel expression between normal and chondrosarcoma tissues. Results Results showed that the expression of ClC-3 chloride channel in the normal chondrocyte was thinner, since it showed distinct differentiation among chondrosarcoma specimens. Interestingly, we noticed that the moderately-differentiated chondrosarcoma (MDC) and the poorly-differentiated chondrosarcoma (PDC) exhibited 94.44% of ClC-3 chloride channel. Besides, the subcellular localization of ClC-3 chloride channel was changed in association with malignant degree changes. The subcellular localization of ClC-3 chloride channel in the MDC and PDC tissue was localized in the cytoplasm and both nucleus and cytoplasm: 83.33% (5 out of 6 cases) and 91.66% (11 out of 12 cases) respectively. On the other hand, we noticed that patient age and gender could have a relation with ClC-3 chloride channel expression; 30- to 60-year-old males showed more expression. Conclusions These results demonstrated a high frequency of ClC-3 chloride channel overexpression and subcellular localization differences in MDC and PDC tissue, suggesting a specific role of ClC-3 chloride channel in the pathogenesis of chondrosarcoma.
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Affiliation(s)
- Zhiqin Deng
- Department of Microsurgery and Orthopedic Trauma, The First Affiliated Hospital of Sun Yat-sen University, Sun Yat-sen University, Guangzhou, Guangdong, China (mainland).,Guangdong Provincial Research Center for Artificial Intelligence and Digital Orthopedic Technology, Hand and Foot Surgery Department, Shenzhen Second People's Hospital (The First Hospital Affiliated to Shenzhen University), Shenzhen, Guangdong, China (mainland)
| | - Wencui Li
- Guangdong Provincial Research Center for Artificial Intelligence and Digital Orthopedic Technology, Hand and Foot Surgery Department, Shenzhen Second People's Hospital (The First Hospital Affiliated to Shenzhen University), Shenzhen, Guangdong, China (mainland)
| | - Murad Alahdal
- Guangdong Provincial Research Center for Artificial Intelligence and Digital Orthopedic Technology, Hand and Foot Surgery Department, Shenzhen Second People's Hospital (The First Hospital Affiliated to Shenzhen University), Shenzhen, Guangdong, China (mainland)
| | - Ningfeng Zhang
- Guangdong Provincial Research Center for Artificial Intelligence and Digital Orthopedic Technology, Hand and Foot Surgery Department, Shenzhen Second People's Hospital (The First Hospital Affiliated to Shenzhen University), Shenzhen, Guangdong, China (mainland)
| | - Junxiong Xie
- Guangdong Provincial Research Center for Artificial Intelligence and Digital Orthopedic Technology, Hand and Foot Surgery Department, Shenzhen Second People's Hospital (The First Hospital Affiliated to Shenzhen University), Shenzhen, Guangdong, China (mainland)
| | - Xiaotian Hu
- Guangdong Provincial Research Center for Artificial Intelligence and Digital Orthopedic Technology, Hand and Foot Surgery Department, Shenzhen Second People's Hospital (The First Hospital Affiliated to Shenzhen University), Shenzhen, Guangdong, China (mainland)
| | - Yang Chen
- Guangdong Provincial Research Center for Artificial Intelligence and Digital Orthopedic Technology, Hand and Foot Surgery Department, Shenzhen Second People's Hospital (The First Hospital Affiliated to Shenzhen University), Shenzhen, Guangdong, China (mainland)
| | - Huankun Fang
- Guangdong Provincial Research Center for Artificial Intelligence and Digital Orthopedic Technology, Hand and Foot Surgery Department, Shenzhen Second People's Hospital (The First Hospital Affiliated to Shenzhen University), Shenzhen, Guangdong, China (mainland)
| | - Li Duan
- Guangdong Provincial Research Center for Artificial Intelligence and Digital Orthopedic Technology, Hand and Foot Surgery Department, Shenzhen Second People's Hospital (The First Hospital Affiliated to Shenzhen University), Shenzhen, Guangdong, China (mainland)
| | - Liqiang Gu
- Department of Microsurgery and Orthopedic Trauma, The First Affiliated Hospital of Sun Yat-sen University, Sun Yat-sen University, Guangzhou, Guangdong, China (mainland)
| | - Daping Wang
- Guangdong Provincial Research Center for Artificial Intelligence and Digital Orthopedic Technology, Hand and Foot Surgery Department, Shenzhen Second People's Hospital (The First Hospital Affiliated to Shenzhen University), Shenzhen, Guangdong, China (mainland)
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Li Y, Wu C, Gu J, Li D, Yang Y. A novel mutation associated with Type III Bartter syndrome: A report of five cases. Mol Med Rep 2019; 20:65-72. [PMID: 31115572 DOI: 10.3892/mmr.2019.10255] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 02/06/2019] [Indexed: 11/05/2022] Open
Abstract
The clinical, biochemical and mutation spectra of Chinese patients with Type III Bartter syndrome (type III BS), a rare autosomal recessive disorder, were investigated. A total of five unrelated Chinese patients aged 8 months to 24 years were diagnosed with type III BS via analysis of biochemical markers, including chloride, potassium and calcium, and genetic sequencing. The levels of insulin‑like growth factor‑1 (IGF‑1) were evaluated via ELISA and a mutation study of cultured amniocytes was conducted for prenatal diagnosis. The child patients were admitted for polydipsia, polyuria, myasthenia and developmental delay, whereas the adult patients were hospitalized for limb numbness, polydipsia and polyuria. Nine variants in the chloride voltage‑gated channel Kb (CLCNKB) gene were detected, including eight sequence variants and one whole CLCNKB gene deletion. One sequence variant (c.1967T>C) was novel, whereas the remaining variants (c.595G>T, c.908A>C, c.1004T>C, c.1312C>T, c.1334_1335delCT and c.1718C>A) and the whole gene deletion had been previously reported. The whole gene deletion was frequently observed in patients with early‑onset type III BS in the present study. Two patients showed IGF‑1 deficiency with normal growth hormone level. All patients were treated with potassium supplementation and indometacin. The mother of one patient underwent amniocentesis during her second pregnancy; the fetus was not affected by type III BS based on screening for sequence variants, and normal development and blood electrolyte analysis following birth confirmed the diagnosis. In conclusion, five cases of type III BS in patients from mainland China were reported. Large deletions were frequently detected, particularly in early‑onset patients; isolated IGF‑1 deficiency was found, one novel sequence variant was identified. Prenatal diagnosis was successfully established using genetic analysis of cultured amniocytes, and may facilitate the prevention of congenital defect of type III BS in the next pregnancy.
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Affiliation(s)
- Yanhan Li
- Department of Laboratory Animal Center, Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300020, P.R. China
| | - Chengcheng Wu
- Department of Cardiology, General Hospital of Tianjin Medical University, Tianjin 300052, P.R. China
| | - Jie Gu
- Department of Laboratory Animal Center, Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300020, P.R. China
| | - Dong Li
- Department of Nephrology, General Hospital of Tianjin Medical University, Tianjin 300052, P.R. China
| | - Yanling Yang
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, P.R. China
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Kong Y, Xu K, Yuan K, Zhu J, Gu W, Liang L, Wang C. Digenetic inheritance of SLC12A3 and CLCNKB genes in a Chinese girl with Gitelman syndrome. BMC Pediatr 2019; 19:114. [PMID: 30999883 PMCID: PMC6471809 DOI: 10.1186/s12887-019-1498-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2018] [Accepted: 04/09/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Gitelman syndrome (GS) is an autosomal recessive disorder and mild variant of classic Bartter syndrome. The latter is caused by defects in the genes CLCNKB and/or CLCNKA (chloride voltage-gated channel Ka and Kb). Patients with GS usually have loss-of-function mutations in SLC12A3. No patient has been reported with compound heterozygous mutations in these genes. We report a girl with GS with a paternally inherited heterozygous mutation in SLC12A3, and maternally inherited heterozygous variants in both CLCNKB and CLCNKA. CASE PRESENTATION In this report, we reported a female patient (8 y and 10 mo) who had growth retardation (111.8 cm, - 1.62 standard deviation height for age) and normal blood pressure, with persistent hypokalemia, hypomagnesemia, hypocalciuria, hypochloremic alkalosis, and elevated levels of plasma renin and aldosterone. Her younger brother, father, and paternal grandmother all had histories of mild low levels of plasma potassium (3.0-3.5 mmol/L), which were rectified by potassium-rich foods. The genomic DNA of the patient, younger brother, parents, and grandparents were screened for gene variations and pedigree analysis using trio whole exome sequencing (WES). The candidate variants were validated by Sanger sequencing. Protein-protein interaction analysis utilized the following databases: Biogrid, MINT, HPRD, STRING, IntAct, iRefIndex, and ppiTrim. The trio WES screening showed that the patient has paternally inherited SLC12A3 p.N359K, and maternally inherited CLCNKB p.L94I. The paternal grandmother and younger brother are both carriers of SLC12A3 p.N359K. According to the STRING database, SLC12A3 and CLCNKB proteins may interact or coexpress with proteins associated with GS. CONCLUSIONS Based on clinical phenotypes, genetic evidence of the pedigree, and previous reported studies, this case of GS indicates a digenetic inheritance of SLC12A3 and CLCNKB that resulted in renal tubular dysfunction perhaps, due to a genetic double-hit mechanism. The putative pathogenicity of the CLCNKB p.L94I variant requires confirmation.
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Affiliation(s)
- Yuanmei Kong
- The First Affiliated Hospital of Zhejiang University, Hangzhou, China
| | - Ke Xu
- Chigene Translational Medicine Research Center, Beijing, China
| | - Ke Yuan
- The First Affiliated Hospital of Zhejiang University, Hangzhou, China
| | - Jianfang Zhu
- The First Affiliated Hospital of Zhejiang University, Hangzhou, China
| | - Weiyue Gu
- Chigene Translational Medicine Research Center, Beijing, China
| | - Li Liang
- The First Affiliated Hospital of Zhejiang University, Hangzhou, China
| | - Chunlin Wang
- The First Affiliated Hospital of Zhejiang University, Hangzhou, China.
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Najafi M, Kordi-Tamandani DM, Behjati F, Sadeghi-Bojd S, Bakey Z, Karimiani EG, Schüle I, Azarfar A, Schmidts M. Mimicry and well known genetic friends: molecular diagnosis in an Iranian cohort of suspected Bartter syndrome and proposition of an algorithm for clinical differential diagnosis. Orphanet J Rare Dis 2019; 14:41. [PMID: 30760291 PMCID: PMC6375149 DOI: 10.1186/s13023-018-0981-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2018] [Accepted: 12/14/2018] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Bartter Syndrome is a rare, genetically heterogeneous, mainly autosomal recessively inherited condition characterized by hypochloremic hypokalemic metabolic alkalosis. Mutations in several genes encoding for ion channels localizing to the renal tubules including SLC12A1, KCNJ1, BSND, CLCNKA, CLCNKB, MAGED2 and CASR have been identified as underlying molecular cause. No genetically defined cases have been described in the Iranian population to date. Like for other rare genetic disorders, implementation of Next Generation Sequencing (NGS) technologies has greatly facilitated genetic diagnostics and counseling over the last years. In this study, we describe the clinical, biochemical and genetic characteristics of patients from 15 Iranian families with a clinical diagnosis of Bartter Syndrome. RESULTS Age range of patients included in this study was 3 months to 6 years and all patients showed hypokalemic metabolic alkalosis. 3 patients additionally displayed hypercalciuria, with evidence of nephrocalcinosis in one case. Screening by Whole Exome Sequencing (WES) and long range PCR revealed that 12/17 patients (70%) had a deletion of the entire CLCNKB gene that was previously identified as the most common cause of Bartter Syndrome in other populations. 4/17 individuals (approximately 25% of cases) were found to suffer in fact from pseudo-Bartter syndrome resulting from congenital chloride diarrhea due to a novel homozygous mutation in the SLC26A3 gene, Pendred syndrome due to a known homozygous mutation in SLC26A4, Cystic Fibrosis (CF) due to a novel mutation in CFTR and apparent mineralocorticoid excess syndrome due to a novel homozygous loss of function mutation in HSD11B2 gene. 1 case (5%) remained unsolved. CONCLUSIONS Our findings demonstrate deletion of CLCNKB is the most common cause of Bartter syndrome in Iranian patients and we show that age of onset of clinical symptoms as well as clinical features amongst those patients are variable. Further, using WES we were able to prove that nearly 1/4 patients in fact suffered from Pseudo-Bartter Syndrome, reversing the initial clinical diagnosis with important impact on the subsequent treatment and clinical follow up pathway. Finally, we propose an algorithm for clinical differential diagnosis of Bartter Syndrome.
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Affiliation(s)
- Maryam Najafi
- Genome Research Division, Human Genetics department, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525KL, Nijmegen, The Netherlands.,Departement of Biology, University of Sistan and Baluchestan, Zahedan, Iran
| | | | - Farkhondeh Behjati
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Simin Sadeghi-Bojd
- Children and Adolescents Health Research Center, resistant tuberculosis institute, Zahedan University of Medical Sciences, Zahedan, Iran
| | - Zeineb Bakey
- Genome Research Division, Human Genetics department, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525KL, Nijmegen, The Netherlands.,Center for Pediatrics and Adolescent Medicine, Freiburg University Hospital, Freiburg University Faculty of Medicine, Mathildenstrasse 1, 79112, Freiburg, Germany
| | - Ehsan Ghayoor Karimiani
- Razavi Cancer Research, Razavi Hospital, Imam Reza International University, Mashhad, Iran.,Next Generation Genetic Polyclinic, Mashhad, Iran
| | - Isabel Schüle
- Center for Pediatrics and Adolescent Medicine, Freiburg University Hospital, Freiburg University Faculty of Medicine, Mathildenstrasse 1, 79112, Freiburg, Germany
| | - Anoush Azarfar
- Department of Pediatrics, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Miriam Schmidts
- Genome Research Division, Human Genetics department, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525KL, Nijmegen, The Netherlands. .,Center for Pediatrics and Adolescent Medicine, Freiburg University Hospital, Freiburg University Faculty of Medicine, Mathildenstrasse 1, 79112, Freiburg, Germany. .,Center for Pediatrics and Adolescent Medicine, University Hospital Freiburg, 79112, Freiburg, Germany.
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Abstract
Bartter and Gitelman syndromes are conditions characterized by renal salt-wasting. Clinical presentations range from severe antenatal disease to asymptomatic with incidental diagnosis. Hypokalemic hypochloremic metabolic alkalosis is the common feature. Bartter variants may be associated with polyuria and weakness. Gitelman syndrome is often subtle, and typically diagnosed later life with incidental hypokalemia and hypomagnesemia. Treatment may involve fluid and electrolyte replenishment, prostaglandin inhibition, and renin-angiotensin-aldosterone system axis disruption. Investigators have identified causative mutations but genotypic-phenotypic correlations are still being characterized. Collaborative registries will allow improved classification schema and development of effective treatments.
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Affiliation(s)
- Rosanna Fulchiero
- Department of Pediatrics, Inova Children's Hospital, 3300 Gallows Road, Falls Church, VA 22042, USA
| | - Patricia Seo-Mayer
- Department of Pediatrics, Inova Children's Hospital, 3300 Gallows Road, Falls Church, VA 22042, USA; Division of Nephrology and Hypertension, Pediatric Specialists of Virginia, 3023 Hamaker Court, Suite 600, Fairfax, VA 22031, USA; Virginia Commonwealth School of Medicine, Richmond, VA, USA.
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Abstract
PURPOSE OF REVIEW Antenatal Bartter's syndrome (aBS) is the most severe form of Bartter's syndrome, requiring close follow-up, in particular during the neonatal period, primarily because of prematurity. The recent identification of a novel and very severe form of aBS merits an update on this topic. RECENT FINDING Despite the identification of several genes involved in Bartter's syndrome, about 20% of patients clinically diagnosed with aBS remained without genetic explanation for decades. We recently identified mutations in MAGED2 as a cause of an X-linked form of aBS characterized by a very early onset of severe polyhydramnios and extreme prematurity leading to high mortality. Remarkably, all symptoms in surviving patients with MAGE-D2 mutations resolve spontaneously, within weeks after preterm birth. Interestingly, MAGE-D2 affects the expression of the sodium chloride cotransporters NKCC2 and NCC, explaining thereby the severity of the disease. Importantly, a more recent analysis of MAGED2 in a large French cohort of patients with aBS confirmed our data and showed that females can also be affected. SUMMARY MAGE-D2 is critical for renal salt reabsorption in the fetus, amniotic fluid volume regulation, and maintenance of pregnancy. Most importantly, MAGED2 must be included in the genetic screening of every form of aBS.
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Teulon J, Planelles G, Sepúlveda FV, Andrini O, Lourdel S, Paulais M. Renal Chloride Channels in Relation to Sodium Chloride Transport. Compr Physiol 2018; 9:301-342. [DOI: 10.1002/cphy.c180024] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Abstract
Bartter syndrome is an inherited renal tubular disorder caused by a defective salt reabsorption in the thick ascending limb of loop of Henle, resulting in salt wasting, hypokalemia, and metabolic alkalosis. Mutations of several genes encoding the transporters and channels involved in salt reabsorption in the thick ascending limb cause different types of Bartter syndrome. A poor phenotype-genotype relationship due to the interaction with other cotransporters and different degrees of compensation through alternative pathways is currently reported. However, phenotypic identification still remains the first step to guide the suspicion of Bartter syndrome. Given the rarity of the syndrome, and the lack of genetic characterization in most cases, limited clinical evidence for treatment is available and the therapy is based mainly on the comprehension of renal physiology and relies on the physician's personal experiences. A better understanding of the mutated channels and transporters could possibly generate targets for specific treatment in the future, also encompassing drugs aiming to correct deficiencies in folding or plasma membrane expression of the mutated proteins.
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Affiliation(s)
- Tamara da Silva Cunha
- Nephrology Division, Universidade Federal de São Paulo (UNIFESP), Escola Paulista de Medicina, São Paulo, Brazil,
| | - Ita Pfeferman Heilberg
- Nephrology Division, Universidade Federal de São Paulo (UNIFESP), Escola Paulista de Medicina, São Paulo, Brazil,
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Wang C, Chen Y, Zheng B, Zhu M, Fan J, Wang J, Jia Z, Huang S, Zhang A. Novel compound heterozygous CLCNKB gene mutations (c.1755A>G/c.848_850delTCT) cause classic Bartter syndrome. Am J Physiol Renal Physiol 2018; 315:F844-F851. [PMID: 29442545 DOI: 10.1152/ajprenal.00077.2017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Inactivated variants in CLCNKB gene encoding the basolateral chloride channel ClC-Kb cause classic Bartter syndrome characterized by hypokalemic metabolic alkalosis and hyperreninemic hyperaldosteronism. Here, we identified two cBS siblings presenting hypokalemia in a Chinese family due to novel compound heterozygous CLCNKB mutations (c.848_850delTCT/c.1755A>G). Compound heterozygosity was confirmed by amplifying and sequencing the patient's genomic DNA. The synonymous mutation c.1755A>G (Thr585Thr) was located at +2 bp from the 5' splice donor site in exon 15. Further transcript analysis demonstrated that this single nucleotide mutation causes exclusion of exon 15 in the cDNA from the proband and his mother. Furthermore, we investigated the expression and protein trafficking change of c.848_850delTCT (ΔTCT) and exon 15 deletion (ΔE15) mutation in vitro. The ΔE15 mutation markedly decreased the expression of ClC-Kb and resulted in a low-molecular-weight band (~55 kDa) trapping in the endoplasmic reticulum, while the ΔTCT mutant only decreased the total and plasma membrane ClC-Kb protein expression but did not affect the subcellular localization. Finally, we studied the physiological functions of mutations by using whole cell patch-clamp and found that the ΔE15 or ΔTCT mutation decreased the current of the ClC-Kb/barttin channel. These results suggested that the compound defective mutations of the CLCNKB gene are the molecular mechanism of the two cBS siblings.
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Affiliation(s)
- Chunli Wang
- Nanjing Key Laboratory of Pediatrics, Children's Hospital of Nanjing Medical University , Nanjing , China
| | - Ying Chen
- Department of Nephrology, Children's Hospital of Nanjing Medical University , Nanjing , China
| | - Bixia Zheng
- Nanjing Key Laboratory of Pediatrics, Children's Hospital of Nanjing Medical University , Nanjing , China
| | - Mengshu Zhu
- Nanjing Key Laboratory of Pediatrics, Children's Hospital of Nanjing Medical University , Nanjing , China
| | - Jia Fan
- Department of Physiology, Nanjing Medical University , Nanjing , China
| | - Juejin Wang
- Department of Physiology, Nanjing Medical University , Nanjing , China
| | - Zhanjun Jia
- Nanjing Key Laboratory of Pediatrics, Children's Hospital of Nanjing Medical University , Nanjing , China
| | - Songming Huang
- Department of Nephrology, Children's Hospital of Nanjing Medical University , Nanjing , China.,Jiangsu Key Laboratory of Pediatrics, Nanjing Medical University , Nanjing , China
| | - Aihua Zhang
- Department of Nephrology, Children's Hospital of Nanjing Medical University , Nanjing , China.,Jiangsu Key Laboratory of Pediatrics, Nanjing Medical University , Nanjing , China
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