1
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Greenberg D, Rosenblum ND, Tonelli M. The multifaceted links between hearing loss and chronic kidney disease. Nat Rev Nephrol 2024; 20:295-312. [PMID: 38287134 DOI: 10.1038/s41581-024-00808-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/04/2024] [Indexed: 01/31/2024]
Abstract
Hearing loss affects nearly 1.6 billion people and is the third-leading cause of disability worldwide. Chronic kidney disease (CKD) is also a common condition that is associated with adverse clinical outcomes and high health-care costs. From a developmental perspective, the structures responsible for hearing have a common morphogenetic origin with the kidney, and genetic abnormalities that cause familial forms of hearing loss can also lead to kidney disease. On a cellular level, normal kidney and cochlea function both depend on cilial activities at the apical surface, and kidney tubular cells and sensory epithelial cells of the inner ear use similar transport mechanisms to modify luminal fluid. The two organs also share the same collagen IV basement membrane network. Thus, strong developmental and physiological links exist between hearing and kidney function. These theoretical considerations are supported by epidemiological data demonstrating that CKD is associated with a graded and independent excess risk of sensorineural hearing loss. In addition to developmental and physiological links between kidney and cochlear function, hearing loss in patients with CKD may be driven by specific medications or treatments, including haemodialysis. The associations between these two common conditions are not commonly appreciated, yet have important implications for research and clinical practice.
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Affiliation(s)
- Dina Greenberg
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, Temerty Faculty of Medicine, Toronto, Ontario, Canada
| | - Norman D Rosenblum
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, Temerty Faculty of Medicine, Toronto, Ontario, Canada
- Department of Paediatrics, Temerty Faculty of Medicine, Toronto, Ontario, Canada
| | - Marcello Tonelli
- Department of Medicine, University of Calgary, Calgary, Alberta, Canada.
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2
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Koo KC, Halawani A, Wong VK, Lange D, Chew BH. Monogenic features of urolithiasis: A comprehensive review. Asian J Urol 2024; 11:169-179. [PMID: 38680588 PMCID: PMC11053333 DOI: 10.1016/j.ajur.2023.03.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Accepted: 03/28/2023] [Indexed: 05/01/2024] Open
Abstract
Objective Urolithiasis formation has been attributed to environmental and dietary factors. However, evidence is accumulating that genetic background can contribute to urolithiasis formation. Advancements in the identification of monogenic causes using high-throughput sequencing technologies have shown that urolithiasis has a strong heritable component. Methods This review describes monogenic factors implicated in a genetic predisposition to urolithiasis. Peer-reviewed journals were evaluated by a PubMed search until July 2023 to summarize disorders associated with monogenic traits, and discuss clinical implications of identification of patients genetically susceptible to urolithiasis formation. Results Given that more than 80% of urolithiases cases are associated with calcium accumulation, studies have focused mainly on monogenetic contributors to hypercalciuric urolithiases, leading to the identification of receptors, channels, and transporters involved in the regulation of calcium renal tubular reabsorption. Nevertheless, available candidate genes and linkage methods have a low resolution for evaluation of the effects of genetic components versus those of environmental, dietary, and hormonal factors, and genotypes remain undetermined in the majority of urolithiasis formers. Conclusion The pathophysiology underlying urolithiasis formation is complex and multifactorial, but evidence strongly suggests the existence of numerous monogenic causes of urolithiasis in humans.
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Affiliation(s)
- Kyo Chul Koo
- Department of Urology, Yonsei University College of Medicine, Seoul, Republic of Korea
| | | | - Victor K.F. Wong
- Department of Urological Sciences, University of British Columbia, Stone Centre at Vancouver General Hospital, Vancouver, British Columbia, Canada
| | - Dirk Lange
- Department of Urological Sciences, University of British Columbia, Stone Centre at Vancouver General Hospital, Vancouver, British Columbia, Canada
| | - Ben H. Chew
- Department of Urological Sciences, University of British Columbia, Stone Centre at Vancouver General Hospital, Vancouver, British Columbia, Canada
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3
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Woo HA, Lee H, Choi YH, Min J, Kang HG, Ahn YH, Lee HK. Clinical outcomes of nephrocalcinosis in preschool-age children: association between nephrocalcinosis improvement and long-term kidney function. Front Pediatr 2023; 11:1214704. [PMID: 37900686 PMCID: PMC10603223 DOI: 10.3389/fped.2023.1214704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Accepted: 09/25/2023] [Indexed: 10/31/2023] Open
Abstract
Background We evaluated the long-term clinical outcomes of nephrocalcinosis (NC) according to etiology and grade in preschool-age children with NC. Methods We retrospectively analyzed the clinical outcomes and disease grade of children with NC classified into three groups according to etiology: prematurity, tubular disorders, and others. Results Overall, 67 children were diagnosed with NC [median age, 0.76 years; interquartile range (IQR) 0.46-2.14 years]. The etiologies of NC included prematurity (28.4%), tubular disorders (25.4%), and others (46.3%). Moreover, 56 (83.6%) children were asymptomatic and diagnosed accidentally through kidney ultrasonography. Newly diagnosed underlying diseases were greater in the tubular disorders group than in the other two groups (P = 0.001). Significantly more newly diagnosed NCs were grade 3 than grade 1 (P = 0.003). The median estimated glomerular filtration rate (eGFR) changed from 96.1 (IQR 68.8-119.2) ml/min/1.72 m2 at diagnosis to 90.9 (IQR 76.4-106.4) ml/min/1.72 m2 at the last follow-up, without a significant difference (P = 0.096). Changes in the kidney function did not differ according to etiology. However, patients without improvement in NC grade showed a decrease in eGFR from 98.1 (IQR 71.1-132.9) to 87.4 (IQR 74.0-104.1) ml/min/1.73 m2 (P = 0.023), while patients with improved NC grade did not show any change in the kidney function. Conclusions Early recognition, especially in NC grade 3, can help uncover further diagnoses, such as tubular disorders. Long-term kidney function depends on whether the NC grade improves.
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Affiliation(s)
- Hyun Ah Woo
- Department of Pediatrics, Seoul National University Children’s Hospital, Seoul, Republic of Korea
| | - Hyeonju Lee
- Department of Pediatrics, Seoul National University Children’s Hospital, Seoul, Republic of Korea
| | - Young Hun Choi
- Department of Radiology, Seoul National University Hospital, Seoul, Republic of Korea
| | - Jeesu Min
- Department of Pediatrics, Chungnam National University Sejong Hospital, Sejong, Republic of Korea
| | - Hee Gyung Kang
- Department of Pediatrics, Seoul National University Children’s Hospital, Seoul, Republic of Korea
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Republic of Korea
- Kidney Research Institute, Seoul National University Medical Research Center, Seoul, Republic of Korea
| | - Yo Han Ahn
- Department of Pediatrics, Seoul National University Children’s Hospital, Seoul, Republic of Korea
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Republic of Korea
- Kidney Research Institute, Seoul National University Medical Research Center, Seoul, Republic of Korea
| | - Hyun Kyung Lee
- Department of Pediatrics, Kangwon National University Children's Hospital, Chuncheon, Republic of Korea
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4
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Guo W, Ji P, Xie Y. Genetic Diagnosis and Treatment of Inherited Renal Tubular Acidosis. KIDNEY DISEASES (BASEL, SWITZERLAND) 2023; 9:371-383. [PMID: 37901710 PMCID: PMC10601937 DOI: 10.1159/000531556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 06/12/2023] [Indexed: 10/31/2023]
Abstract
Background Renal tubular acidosis (RTA) is caused by various disruptions to the secretion of H+ by distal renal tubules and/or dysfunctional reabsorption of HCO3- by proximal renal tubules, which causes renal acidification dysfunction, ultimately leading to a clinical syndrome characterized by hyperchloremic metabolic acidosis with a normal anion gap. With the development of molecular genetics and gene sequencing technology, inherited RTA has also attracted attention, and an increasing number of RTA-related pathogenic genes have been discovered and reported. Summary This paper focuses on the latest progress in the research of inherited RTA and systematically reviews the pathogenic genes, protein functions, clinical manifestations, internal relationship between genotypes and clinical phenotypes, diagnostic clues, differential diagnosis, and treatment strategies associated with inherited RTA. This paper aims to deepen the understanding of inherited RTA and reduce the missed diagnosis and misdiagnosis of RTA. Key Messages This review systematically summarizes the pathogenic genes, pathophysiological mechanisms, differential diagnosis, and treatment of different types of inherited RTA, which has good clinical value for guiding the diagnosis and treatment of inherited RTA.
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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, China
- School of Medicine, Nankai University, Tianjin, 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, 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, China
- School of Medicine, Nankai University, Tianjin, China
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5
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Indrawinata K, Argiropoulos P, Sugita S. Structural and functional understanding of disease-associated mutations in V-ATPase subunit a1 and other isoforms. Front Mol Neurosci 2023; 16:1135015. [PMID: 37465367 PMCID: PMC10352029 DOI: 10.3389/fnmol.2023.1135015] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Accepted: 06/09/2023] [Indexed: 07/20/2023] Open
Abstract
The vacuolar-type ATPase (V-ATPase) is a multisubunit protein composed of the cytosolic adenosine triphosphate (ATP) hydrolysis catalyzing V1 complex, and the integral membrane complex, Vo, responsible for proton translocation. The largest subunit of the Vo complex, subunit a, enables proton translocation upon ATP hydrolysis, mediated by the cytosolic V1 complex. Four known subunit a isoforms (a1-a4) are expressed in different cellular locations. Subunit a1 (also known as Voa1), the neural isoform, is strongly expressed in neurons and is encoded by the ATP6V0A1 gene. Global knockout of this gene in mice causes embryonic lethality, whereas pyramidal neuron-specific knockout resulted in neuronal cell death with impaired spatial and learning memory. Recently reported, de novo and biallelic mutations of the human ATP6V0A1 impair autophagic and lysosomal activities, contributing to neuronal cell death in developmental and epileptic encephalopathies (DEE) and early onset progressive myoclonus epilepsy (PME). The de novo heterozygous R740Q mutation is the most recurrent variant reported in cases of DEE. Homology studies suggest R740 deprotonates protons from specific glutamic acid residues in subunit c, highlighting its importance to the overall V-ATPase function. In this paper, we discuss the structure and mechanism of the V-ATPase, emphasizing how mutations in subunit a1 can lead to lysosomal and autophagic dysfunction in neurodevelopmental disorders, and how mutations to the non-neural isoforms, a2-a4, can also lead to various genetic diseases. Given the growing discovery of disease-causing variants of V-ATPase subunit a and its function as a pump-based regulator of intracellular organelle pH, this multiprotein complex warrants further investigation.
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Affiliation(s)
- Karen Indrawinata
- Division of Translational and Experimental Neuroscience, Krembil Brain Institute, University Health Network, Toronto, ON, Canada
| | - Peter Argiropoulos
- Division of Translational and Experimental Neuroscience, Krembil Brain Institute, University Health Network, Toronto, ON, Canada
| | - Shuzo Sugita
- Division of Translational and Experimental Neuroscience, Krembil Brain Institute, University Health Network, Toronto, ON, Canada
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
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6
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Huang L, Qi C, Zhu G, Ding J, Yuan L, Sun J, He X, Wang X. Genetic testing enables a precision medicine approach for nephrolithiasis and nephrocalcinosis in pediatrics: a single-center cohort. Mol Genet Genomics 2022; 297:1049-1061. [PMID: 35612621 PMCID: PMC9250473 DOI: 10.1007/s00438-022-01897-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Accepted: 01/14/2022] [Indexed: 11/11/2022]
Abstract
Objective Hereditary factors are the main cause of pediatric nephrolithiasis (NL)/nephrocalcinosis (NC). We summarized the genotype–phenotype correlation of hereditary NL/NC in our center, to evaluate the role of genetic testing in early diagnosis. Methods The clinical data of 32 NL/NC cases, which were suspected to have an inherited basis, were retrospectively analyzed from May 2017 to August 2020. The trio-whole exome sequencing was used as the main approach for genetic testing, variants were confirmed by Sanger sequencing, and pathogenicity analysis according to protein function was predicted with custom-developed software. Results Causative monogenic mutations were detected in 24 of 32 NL/NC patients, and copy number variation was detected in one patient. A summary of manifestations in patients with inherited diseases revealed a significant degree of growth retardation, increased urinary excretion of the low-molecular weight protein, hypercalciuria, electrolyte imbalances, and young age of onset to be common in heredity disease. In addition, some patients had abnormal renal function (3 ppm 25). The most frequent pathology identified was distal renal tubular acidosis (with inclusion of SLC4A1, ATP6V1B1, and ATP6VOA4 genes), followed by Dent disease (CLCN5 and OCRL1 genes), primary hyperoxaluria (PH) (AGXT and HOGA1 genes) and Kabuki syndrome (KMT2D gene), which was more likely to present as NC or recurrent stone and having a higher correlation with a specific biochemical phenotype and extrarenal phenotype. Conclusion The etiology of NL/NC is heterogeneous. This study explored in depth the relationship between phenotype and genotype in 32 patients, and confirmed that genetic testing and clinical phenotype evaluation enable the precision medicine approach to treating patients. Supplementary Information The online version contains supplementary material available at 10.1007/s00438-022-01897-z.
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Affiliation(s)
- Lin Huang
- Department of Nephrology, Wuhan Children's Hospital (Wuhan Maternal and Child Healthcare Hospital), Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430000, China
| | - Chang Qi
- Department of Nephrology, Wuhan Children's Hospital (Wuhan Maternal and Child Healthcare Hospital), Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430000, China
| | - Gaohong Zhu
- Department of Nephrology, Wuhan Children's Hospital (Wuhan Maternal and Child Healthcare Hospital), Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430000, China
| | - Juanjuan Ding
- Department of Nephrology, Wuhan Children's Hospital (Wuhan Maternal and Child Healthcare Hospital), Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430000, China
| | - Li Yuan
- Department of Ultrasonic Imaging, Wuhan Children's Hospital (Wuhan Maternal and Child Healthcare Hospital), Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430000, China
| | - Jie Sun
- Department of Ultrasonic Imaging, Wuhan Children's Hospital (Wuhan Maternal and Child Healthcare Hospital), Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430000, China
| | - Xuelian He
- Department of Central Laboratory, Wuhan Children's Hospital (Wuhan Maternal and Child Healthcare Hospital), Tongji Medical College, Huazhong University of Science and Technology, 100 Hong Kong Road, Wuhan, 430014, Hubei, China
| | - Xiaowen Wang
- Department of Nephrology, Wuhan Children's Hospital (Wuhan Maternal and Child Healthcare Hospital), Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430000, China.
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7
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Singh P, Harris PC, Sas DJ, Lieske JC. The genetics of kidney stone disease and nephrocalcinosis. Nat Rev Nephrol 2022; 18:224-240. [PMID: 34907378 DOI: 10.1038/s41581-021-00513-4] [Citation(s) in RCA: 49] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/17/2021] [Indexed: 12/15/2022]
Abstract
Kidney stones (also known as urinary stones or nephrolithiasis) are highly prevalent, affecting approximately 10% of adults worldwide, and the incidence of stone disease is increasing. Kidney stone formation results from an imbalance of inhibitors and promoters of crystallization, and calcium-containing calculi account for over 80% of stones. In most patients, the underlying aetiology is thought to be multifactorial, with environmental, dietary, hormonal and genetic components. The advent of high-throughput sequencing techniques has enabled a monogenic cause of kidney stones to be identified in up to 30% of children and 10% of adults who form stones, with ~35 different genes implicated. In addition, genome-wide association studies have implicated a series of genes involved in renal tubular handling of lithogenic substrates and of inhibitors of crystallization in stone disease in the general population. Such findings will likely lead to the identification of additional treatment targets involving underlying enzymatic or protein defects, including but not limited to those that alter urinary biochemistry.
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Affiliation(s)
- Prince Singh
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA
| | - Peter C Harris
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA.,Division of Molecular Biology and Biochemistry, Mayo Clinic, Rochester, MN, USA
| | - David J Sas
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA.,Division of Pediatric Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA
| | - John C Lieske
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA. .,Division of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA.
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8
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Zhang R, Chen Z, Song Q, Wang S, Liu Z, Zhao X, Shi X, Guo W, Lang Y, Bottillo I, Shao L. Identification of seven exonic variants in the SLC4A1, ATP6V1B1, and ATP6V0A4 genes that alter RNA splicing by minigene assay. Hum Mutat 2021; 42:1153-1164. [PMID: 34157794 DOI: 10.1002/humu.24246] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 06/02/2021] [Accepted: 06/19/2021] [Indexed: 12/25/2022]
Abstract
Primary distal renal tubular acidosis (dRTA) is a rare tubular disease associated with variants in SLC4A1, ATP6V0A4, ATP6V1B1, FOXⅠ1, or WDR72 genes. Currently, there is growing evidence that all types of exonic variants can alter splicing regulatory elements, affecting the precursor messenger RNA (pre-mRNA) splicing process. This study was to determine the consequences of variants associated with dRTA on pre-mRNA splicing combined with predictive bioinformatics tools and minigene assay. As a result, among the 15 candidate variants, 7 variants distributed in SLC4A1 (c.1765C>T, p.Arg589Cys), ATP6V1B1 (c.368G>T, p.Gly123Val; c.370C>T, p.Arg124Trp; c.484G>T, p.Glu162* and c.1102G>A, p.Glu368Lys) and ATP6V0A4 genes (c.322C>T, p.Gln108* and c.1572G>A, p.Pro524Pro) were identified to result in complete or incomplete exon skipping by either disruption of exonic splicing enhancers (ESEs) and generation of exonic splicing silencers, or interference with the recognition of the classic splicing site, or both. To our knowledge, this is the first study on pre-mRNA splicing of exonic variants in the dRTA-related genes. These results highlight the importance of assessing the effects of exonic variants at the mRNA level and suggest that minigene analysis is an effective tool for evaluating the effects of splicing on variants in vitro.
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Affiliation(s)
- Ruixiao Zhang
- Department of Nephrology, The Affiliated Qingdao Municipal Hospital of Qingdao University, Qingdao, China
| | - Zeqing Chen
- Academy for Engineering and Technology, Fudan University, Shanghai, China
| | - Qijing Song
- Emergency Center, People's Hospital of Jimo District, Qingdao, China
| | - Sai Wang
- Department of Nephrology, The Affiliated Qingdao Municipal Hospital of Qingdao University, Qingdao, China.,Department of Dermatology, Peking University First Hospital, Beijing, China
| | - Zhiying Liu
- Department of Nephrology, The Affiliated Qingdao Municipal Hospital of Qingdao University, Qingdao, China
| | - Xiangzhong Zhao
- Central Laboratory, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Xiaomeng Shi
- Department of Nephrology, The Affiliated Qingdao Municipal Hospital of Qingdao University, Qingdao, China
| | - Wencong Guo
- Department of Nephrology, The Affiliated Qingdao Municipal Hospital of Qingdao University, Qingdao, China
| | - Yanhua Lang
- Department of Nephrology, The Affiliated Qingdao Municipal Hospital of Qingdao University, Qingdao, China
| | - Irene Bottillo
- Division of Medical Genetics, Department of Molecular Medicine, San Camillo-Forlanini Hospital, Sapienza University, Rome, Italy
| | - Leping Shao
- Department of Nephrology, The Affiliated Qingdao Municipal Hospital of Qingdao University, Qingdao, China
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9
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Trepiccione F, Walsh SB, Ariceta G, Boyer O, Emma F, Camilla R, Ferraro PM, Haffner D, Konrad M, Levtchenko E, Lopez-Garcia SC, Santos F, Stabouli S, Szczepanska M, Tasic V, Topaloglu R, Vargas-Poussou R, Wlodkowski T, Bockenhauer D. Distal Renal Tubular Acidosis: ERKNet/ESPN Clinical Practice Points. Nephrol Dial Transplant 2021; 36:1585-1596. [PMID: 33914889 DOI: 10.1093/ndt/gfab171] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Indexed: 12/15/2022] Open
Abstract
Distal renal tubular acidosis (dRTA) is characterised by an impaired ability of the distal tubule to excrete acid, leading to metabolic acidosis. Associated complications include bone disease, growth failure, urolithiasis and hypokalaemia. Due to its rarity, there is a limited evidence to guide diagnosis and management, however, available data strongly suggest that metabolic control of the acidosis by alkali supplementation can halt or revert almost all complications. Despite this, cohort studies show that adequate metabolic control is present in only about half of patients, highlighting problems with treatment provision or adherence. With these clinical practice points the authors, part of the working groups tubulopathies in the European Rare Kidney Disease Reference network (ERKnet) and inherited kidney diseases of the European Society for Paediatric Nephrology (ESPN) aim to provide guidance for the management of patients with dRTA to facilitate adequate treatment and establish an initial best practice standard against which treatment of patients can be audited.
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Affiliation(s)
- Francesco Trepiccione
- Department of Translational Medical Sciences, University of Campania "L. Vanvitelli", Naples, Italy
| | - Steven B Walsh
- Department of Renal Medicine, University College London, UK
| | - Gema Ariceta
- Division of Pediatric Nephrology. Hospital Universitario Vall d' Hebron. Universitat Autonoma de Barcelona. Barcelona, Spain
| | - Olivia Boyer
- Pediatric Nephrology, Necker Hospital, APHP, MARHEA, Imagine Institute, Paris University, Paris, France
| | - Francesco Emma
- Division of Nephrology, Bambino Gesu Children's Hospital - IRCCS, Rome, Italy
| | - Roberta Camilla
- Nephrology, Dialysis, Transplantation, Regina Margherita University Hospital, Turin, Italy
| | - Pietro Manuel Ferraro
- U.O.S. Terapia Conservativa della Malattia Renale Cronica, U.O.C. Nefrologia, Dipartimento di Scienze Mediche e Chirurgiche, Fondazione Policlinico Universitario A. Gemelli IRCCS, Roma, Italy.,Dipartimento Universitario di Medicina e Chirurgia Traslazionale, Università Cattolica del Sacro Cuore, Roma, Italy
| | - Dieter Haffner
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School Children's Hospital, Hannover, Germany
| | - Martin Konrad
- Department of General Pediatrics, University Children's Hospital, Muenster, Germany
| | - Elena Levtchenko
- Division of Pediatric Nephrology, University Hospitals Leuven; Department of Development & Regeneration, Katholieke Universiteit Leuven, Belgium
| | - Sergio Camilo Lopez-Garcia
- Department of Renal Medicine, University College London, UK.,Renal Unit, Great Ormond Street Hospital for Children, NHS Foundation Trust, London, UK
| | - Fernando Santos
- Department of Pediatrics, Hospital Universitario Central de Asturias and Área de Pediatría, Dpto. de Medicina, Universidad de Oviedo, Oviedo, Spain
| | - Stella Stabouli
- 1st Department of Pediatrics, Aristotle University, Thessaloniki, Greece
| | | | - Velibor Tasic
- University Children's Hospital, Medical School, Skopje, Macedonia
| | - Rezan Topaloglu
- Department of Pediatric Nephrology, Hacettepe University Faculty of Medicine, Hacettepe University, Ankara, Turkey
| | - Rosa Vargas-Poussou
- Department of Genetics, Centre de Références MARHEA, Hôpital Européen Georges Pompidou Assistance Publique Hôpitaux de Paris, Paris France
| | - Tanja Wlodkowski
- Department of Paediatric Nephrology, University Children's Hospital, Heidelberg, Germany
| | - Detlef Bockenhauer
- Department of General Pediatrics, University Children's Hospital, Muenster, Germany.,Division of Pediatric Nephrology, University Hospitals Leuven; Department of Development & Regeneration, Katholieke Universiteit Leuven, Belgium
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10
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Dawman L, Tiewsoh K, Barman P, Pratyusha K, Chaakchhuak L, Sharawat IK. Phenotype and Genotype Profile of Children with Primary Distal Renal Tubular Acidosis: A 10-Year Experience from a North Indian Teaching Institute. J Pediatr Genet 2021; 11:221-226. [DOI: 10.1055/s-0041-1724114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 01/13/2021] [Indexed: 10/22/2022]
Abstract
AbstractPrimary distal renal tubular acidosis (dRTA) or Type 1 RTA in children is caused by a genetic defect (involved genes ATP6V0A4, ATP6V1B1, SLC4A1, FOXI1, or WDR72), which causes tubular transport defects characterized by an inability to appropriately acidify urine with resultant persistent hyperchloremic metabolic acidosis. Retrospective analysis of 28 children (14 males) under the age of 14 years with dRTA seen from 2010 to 2019 was reviewed, and detailed clinic records were analyzed. The clinical features, investigations, and response to treatment were recorded. The median age of the children at presentation was 30 months (range: 9.25–72 months), and the median age at onset of symptoms was 2 months. All the children had growth failure, polyuria, and polydipsia at presentation. Mean serum potassium, pH, bicarbonate, and anion gap at presentation was 2.3 ± 0.5 mmol/L, 7.22 ± 0.09, 13.28 ± 4.37 mmol/L, and 9.3 ± 2.18, respectively. Mean serum potassium, pH, bicarbonate at follow-up was 3.88 ± 0.6 mmol/L, 7.35 ± 0.06, and 20.13 ± 4.17 mmol/L, respectively. The median z-score for the weight for age and height for age at initial presentation was −4.77 (–7.68 to –3.74) and –4.21 (–5.42 to –2.37) and at follow-up was –3.35 (–5.29 to –1.55) and –3.84 (–5.36 to –1.63), respectively. Twenty-two (78.6%) children had medullary nephrocalcinosis. Four children had sensorineural hearing loss. Seven children had genetic testing done, and six had pathogenic or likely pathogenic variants in ATP6V1B1 and ATP6V0A4 gene. Children with dRTA have a guarded prognosis and ATP6V1B1 and ATP6V0A4 mutations are the most common implicated genetic defect in Indian children with distal RTA.
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Affiliation(s)
- Lesa Dawman
- Department of Pediatrics, Advanced Pediatrics Centre, Post Graduate Institute of Medical Education and Research, Chandigarh, India
| | - Karalanglin Tiewsoh
- Department of Pediatrics, Advanced Pediatrics Centre, Post Graduate Institute of Medical Education and Research, Chandigarh, India
| | - Prabal Barman
- Department of Pediatrics, Advanced Pediatrics Centre, Post Graduate Institute of Medical Education and Research, Chandigarh, India
| | - Kambagiri Pratyusha
- Department of Pediatrics, Advanced Pediatrics Centre, Post Graduate Institute of Medical Education and Research, Chandigarh, India
| | - Lalawmpuia Chaakchhuak
- Department of Pediatrics, Advanced Pediatrics Centre, Post Graduate Institute of Medical Education and Research, Chandigarh, India
| | - Indar Kumar Sharawat
- Department of Pediatrics, All India Institute of Medical Sciences, Rishikesh, Uttarakhand, India
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11
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Bertholet-Thomas A, Guittet C, Manso-Silván MA, Castang A, Baudouin V, Cailliez M, Di Maio M, Gillion-Boyer O, Golubovic E, Harambat J, Klein A, Knebelmann B, Nobili F, Novo R, Podracka L, Roussey-Kesler G, Stylianou C, Granier LA. Efficacy and safety of an innovative prolonged-release combination drug in patients with distal renal tubular acidosis: an open-label comparative trial versus standard of care treatments. Pediatr Nephrol 2021; 36:83-91. [PMID: 32712761 PMCID: PMC7701073 DOI: 10.1007/s00467-020-04693-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 06/16/2020] [Accepted: 06/25/2020] [Indexed: 11/30/2022]
Abstract
BACKGROUND Distal renal tubular acidosis (dRTA), due to impaired acid secretion in the urine, can lead to severe long-term consequences. Standard of care (SoC) oral alkalizers, requiring several daily intakes, are currently used to restore normal plasma bicarbonate levels. A new prolonged-release formulation, ADV7103, has been developed to achieve a sustained effect with an improved dosing scheme. METHODS In a multicenter, open-label, non-inferiority trial (n = 37), patients with dRTA were switched from SoC to ADV7103. Mean plasma bicarbonate values and proportion of responders during steady state therapy with both treatments were compared, as were other blood and urine parameters, as well as acceptability, tolerability, and safety. RESULTS When switching from SoC to ADV7103, the number of daily intakes was reduced from a median of three to twice daily. Mean plasma bicarbonate was increased and non-inferiority of ADV7103 was demonstrated (p < 0.0001, per protocol), as was statistical superiority (p = 0.0008, intention to treat [ITT]), and the response rate increased from 43 to 90% with ADV7103 (p < 0.001, ITT). Urine calcium/citrate ratio was reduced below the threshold for risk of lithogenesis with ADV7103 in 56% of previously non-responders with SoC (p = 0.021, ITT). Palatability was improved (difference [95% CI] of 25 [10.7, 39.2] mm) and gastrointestinal discomfort was reduced (difference [95% CI] of - 14.2 [- 25.9, - 2.6] mm) with ADV7103. CONCLUSIONS Plasma bicarbonate levels and response rate were significantly higher with ADV7103 than with SoC. Urine calcium/citrate ratio, palatability, and gastrointestinal safety were significantly improved, supporting the use of ADV7103 as first-line treatment for dRTA. TRIAL REGISTRATION Registered as EudraCT 2013-002988-25 on the 1st July 2013 Graphical abstract.
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Affiliation(s)
- Aurélia Bertholet-Thomas
- Centre de Référence des Maladies Rénales Rares - Néphrogones - Hôpital Femme Mère Enfant - Filière ORKiD, Hospices Civils de Lyon, Bron, France.
| | | | | | | | | | - Mathilde Cailliez
- Service de Pédiatrie Multidisciplinaire, Hôpital de la Timone, AP-HM, Marseille, France
| | - Massimo Di Maio
- Service de Réanimation Néonatale et Néonatologie, CHU de Nîmes, Nîmes, France
| | - Olivia Gillion-Boyer
- Service de Néphrologie Pédiatrique, Centre de Référence des Maladies Rénales Héréditaires de l'Enfant et de l'Adulte (MARHEA), Institut Imagine, Hôpital Necker-Enfants Malades, Université de Paris, Paris, France
| | - Emilija Golubovic
- Klinički Centar Niš, Klinika za dečije interne bolesti - Odeljenje za nefrologiju, Niš, Serbia
| | - Jérôme Harambat
- Service de Pédiatrie, CHU de Bordeaux, Hôpital Pellegrin-Enfants, Bordeaux, France
| | - Alexandre Klein
- Service de Néphrologie, Pôle DIACOR, Hôpitaux Civils de Colmar, Colmar, France
| | | | - François Nobili
- Service de Pédiatrie 2, Hôpital Jean Minjoz, CHU de Besançon, Besançon, France
| | - Robert Novo
- Service de Néphrologie Pédiatrique, Hôpital Jeanne de Flandre, CHRU de Lille, Lille, France
| | - Ludmila Podracka
- Department of Pediatrics, National Institute of Children's Health, Bratislava, Slovakia
| | - Gwenaëlle Roussey-Kesler
- Unité de Néphrologie et Hémodialyse Pédiatrique, Clinique Médicale Pédiatrique Hôpital Mère-Enfant, CHU de Nantes, Nantes, France
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12
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Atmis B, Cevizli D, Melek E, Bisgin A, Unal I, Anarat A, Bayazit AK. Evaluation of phenotypic and genotypic features of children with distal kidney tubular acidosis. Pediatr Nephrol 2020; 35:2297-2306. [PMID: 32613277 DOI: 10.1007/s00467-020-04685-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 06/16/2020] [Accepted: 06/18/2020] [Indexed: 11/28/2022]
Abstract
BACKGROUND The present study aimed to assess genotype-phenotype correlations with long-term prognosis in children with distal kidney tubular acidosis (dKTA). The kidney function of children with dKTA could be impaired in the long-term. METHODS Thirty-one children with dKTA from 23 families were included in the present study. Demographic features, growth parameters, clinical manifestations, follow-up results, and genetic analysis results of the patients were recorded. RESULTS Eighteen children (58.1%) were male. The median age at diagnosis was 3 months. The median follow-up period was 77 months and the longest was 23.5 years. Eight (28.8%) patients had chronic kidney disease (CKD) stage 2 or 3. Three patients aged 24, 23, and 19 years had CKD stage 3 with an estimated glomerular filtration rate of 54, 57, and 48 mL/min/1.73 m2, respectively. Thirteen patients had mutations in the ATP6V0A4 gene, eight had mutations in the ATP6V1B1 gene, and three had mutations in the SLC4A1 gene. There was no significant correlation between molecular diagnosis and CKD. Growth retardation with a height below a standard deviation (SD) score of - 2 was found in 14 patients (45.1%) at the time of diagnosis. The mean height SD score at the last visit was significantly higher in patients who had adequate metabolic control at > 75% of all visits as compared with that in patients who did not. CONCLUSION Patients with dKTA usually have a good clinical prognosis in childhood with appropriate treatment; however, dRTA is characterized by deterioration of kidney function in adulthood, particularly after puberty.
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Affiliation(s)
- Bahriye Atmis
- Department of Pediatric Nephrology, Cukurova University Faculty of Medicine, Adana, Turkey.
| | - Derya Cevizli
- Department of Pediatric Nephrology, Cukurova University Faculty of Medicine, Adana, Turkey
| | - Engin Melek
- Department of Pediatric Nephrology, Cukurova University Faculty of Medicine, Adana, Turkey
| | - Atil Bisgin
- Department of Medical Genetics, Faculty of Medicine, Cukurova University, Adana, Turkey.,Cukurova University AGENTEM (Adana Genetic Diseases Diagnosis and Treatment Center), Adana, Turkey
| | - Ilker Unal
- Department of Biostatistics, Cukurova University Faculty of Medicine, Adana, Turkey
| | - Ali Anarat
- Department of Pediatric Nephrology, Cukurova University Faculty of Medicine, Adana, Turkey
| | - Aysun K Bayazit
- Department of Pediatric Nephrology, Cukurova University Faculty of Medicine, Adana, Turkey
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13
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More TA, Kedar PS. Genotypic analysis of SLC4A1 A858D mutation in Indian population associated with distal renal tubular Acidosis (dRTA) coupled with hemolytic anemia. Gene 2020; 769:145241. [PMID: 33068675 DOI: 10.1016/j.gene.2020.145241] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 09/27/2020] [Accepted: 10/11/2020] [Indexed: 10/23/2022]
Abstract
INTRODUCTION Although distinctive, distal renal tubular acidosis (dRTA) and Hereditary Spherocytosis (HS) shares a common protein, the anion exchanger1 (AE1) encoded by SLC4A1gene. In spite of this, the co-existence of dRTA and HS has rarely been observed. To date, 23 mutations have been identified in SLC4A1 gene causing both autosomal recessive (AR) and autosomal dominant (AD) forms of dRTA. METHODS We have assessed the applicability of the High Resolution Melting curve (HRM) method for the detection of SLC4A1 (A858D) mutation in 12 Indian families having AR dRTA coupled with HS. The reliability of the HRM analysis was verified by comparing the results of the HRM method with those of conventional methods such as Polymerase Chain Reaction-Restriction Fragment-Length Polymorphism (PCR-RFLP) and Sanger sequencing thereby confirming the diagnosis. RESULTS We here described the clinical, hematological and genetic data of 16 individuals from 12 families having AR dRTA coupled with HS. All patients carried homozygous SLC4A1 (A858D) mutation, whereas their family members had heterozygous A858D obtained by HRM analysis and confirmed by RFLP and Sanger sequencing. CONCLUSION Our data indicates that a missense mutation of A858D in SLC4A1 gene is the most common cause of dRTA coupled with HS in the Indian population. HRM analysis can be used as a rapid screening method for common SLC4A1 mutations that cause AR dRTA in the Indian population.
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Affiliation(s)
- Tejashree Anil More
- Department of Hematogenetics, ICMR-National Institute of Immunohematology, KEM Hospital Campus, Parel, Mumbai 40012, India
| | - Prabhakar S Kedar
- Department of Hematogenetics, ICMR-National Institute of Immunohematology, KEM Hospital Campus, Parel, Mumbai 40012, India.
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14
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Abstract
Renal tubular acidosis (RTA) comprises a group of disorders characterized by low capacity for net acid excretion and persistent hyperchloremic metabolic acidosis, despite preserved glomerular filtration rate. RTA are classified into chiefly three types (1, 2 and 4) based on pathophysiology and clinical and laboratory characteristics. Most patients have primary RTA that presents in infancy with polyuria, growth retardation, rickets and/or hypotonia. Diagnosis requires careful evaluation, including exclusion of other entities that can cause acidosis. A variety of tests, administered stepwise, are useful for the diagnosis and characterization of RTA. A genetic or acquired basis can be determined in majority of patients through focused evaluation. Management involves correction of acidosis and dyselectrolytemia; patients with proximal RTA with Fanconi syndrome and rickets require additional supplements of phosphate and vitamin D.
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Affiliation(s)
- Arvind Bagga
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, 110029, India.
| | - Aditi Sinha
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, 110029, India
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15
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Bertocchio JP, Genetet S, Da Costa L, Walsh SB, Knebelmann B, Galimand J, Bessenay L, Guitton C, De Lafaille R, Vargas-Poussou R, Eladari D, Mouro-Chanteloup I. Red Blood Cell AE1/Band 3 Transports in Dominant Distal Renal Tubular Acidosis Patients. Kidney Int Rep 2020; 5:348-357. [PMID: 32154456 PMCID: PMC7056926 DOI: 10.1016/j.ekir.2019.12.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2019] [Revised: 11/26/2019] [Accepted: 12/31/2019] [Indexed: 11/30/2022] Open
Abstract
Introduction Anion exchanger 1 (AE1) (SLC4A1 gene product) is a membrane protein expressed in both kidney and red blood cells (RBCs): it exchanges extracellular bicarbonate (HCO3–) for intracellular chloride (Cl–) and participates in acid−base homeostasis. AE1 mutations in kidney α-intercalated cells can lead to distal renal tubular acidosis (dRTA). In RBC, AE1 (known as band 3) is also implicated in membrane stability: deletions can cause South Asian ovalocytosis (SAO). Methods We retrospectively collected clinical and biological data from patients harboring dRTA due to a SLC4A1 mutation and analyzed HCO3– and Cl– transports (by stopped-flow spectrophotometry) and expression (by flow cytometry, fluorescence activated cell sorting, and Coomassie blue staining) in RBCs, as well as RBC membrane stability (ektacytometry). Results Fifteen patients were included. All experience nephrolithiasis and/or nephrocalcinosis, 2 had SAO and dRTA (dRTA SAO+), 13 dominant dRTA (dRTA SAO−). The latter did not exert specific RBC membrane anomalies. Both HCO3– and Cl– transports were lower in patients with dRTA SAO+ than in those with dRTA SAO− or controls. Using 3 different extracellular probes, we report a decreased expression (by 52%, P < 0.05) in dRTA SAO+ patients by fluorescence activated cell sorting, whereas total amount of protein was not affected. Conclusion Band 3 transport function and expression in RBCs from dRTA SAO− patients is normal. However, in SAO RBCs, impaired conformation of AE1/band 3 corresponds to an impaired function. Thus, the driver of acid−base defect during dominant dRTA is probably an impaired membrane expression.
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Affiliation(s)
- Jean-Philippe Bertocchio
- Renal and Metabolic Diseases Unit, Assistance Publique-Hôpitaux de Paris, European Georges Pompidou Hospital, Paris, France.,Faculty of Medicine, Paris Descartes University, Paris, France.,Reference Center for Maladies Rénales Héréditaires de l'Enfant et de l'Adulte (MARHEA), Paris, France.,Genito-urinary Medical Oncology and Research Department, MD Anderson Cancer Center, Houston, Texas, USA
| | - Sandrine Genetet
- UMR_S1134, Integrated Red Globule Biology (IRGB), Inserm, University of Paris, Paris, France.,Team 1, Physiology of Normal and Pathologic Red Blood Cell, Institut National de la Transfusion Sanguine (INTS), Paris, France
| | - Lydie Da Costa
- UMR_S1134, Integrated Red Globule Biology (IRGB), Inserm, University of Paris, Paris, France.,UMR_S1134, Inserm, Paris, France.,Service d'Hématologie Biologique, Assistance Publique-Hôpitaux de Paris, Hôpital Robert Debré, Paris, France
| | - Stephen B Walsh
- Department of Renal Medicine, University College of London, London, UK
| | - Bertrand Knebelmann
- Nephrology Department, Assistance Publique-Hôpitaux de Paris, Necker-Enfants Malades Hospital, Paris, France
| | - Julie Galimand
- Service d'Hématologie Biologique, Assistance Publique-Hôpitaux de Paris, Hôpital Robert Debré, Paris, France
| | - Lucie Bessenay
- Pediatrics Department, University Hospital of Clermont-Ferrand, Clermont-Ferrand, France
| | - Corinne Guitton
- Pediatrics Department, Assistance Publique-Hôpitaux de Paris, Hôpital Bicêtre, Le Kremlin Bicêtre, France
| | - Renaud De Lafaille
- Nephrology Department, University Hospital of Bordeaux, Bordeaux, Aquitaine, France
| | - Rosa Vargas-Poussou
- Reference Center for Maladies Rénales Héréditaires de l'Enfant et de l'Adulte (MARHEA), Paris, France.,Institut National pour la Santé et la Recherche Médicale (INSERM), Unité Mixte de Recherche UMRS1138, Cordeliers Research Center, Paris, France.,Genetics Department, Assistance Publique-Hôpitaux de Paris, European Georges Pompidou Hospital, Paris, France
| | - Dominique Eladari
- Renal and Metabolic Diseases Department, CHU de la Réunion, Felix Guyon Hospital, Saint Denis, France.,INSERM, UMRS 1283-European Genomic Institute for Diabetes, Lille, France
| | - Isabelle Mouro-Chanteloup
- UMR_S1134, Integrated Red Globule Biology (IRGB), Inserm, University of Paris, Paris, France.,Team 1, Physiology of Normal and Pathologic Red Blood Cell, Institut National de la Transfusion Sanguine (INTS), Paris, France
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16
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Khan N, Akhtar N, Khan FF, Hussain S, Naeem M. Molecular Diagnosis and Identification of Genetic Variants Underlying Distal Renal Tubular Acidosis in Pakistani Patients Using Whole Exome Sequencing. Genet Test Mol Biomarkers 2020; 24:85-91. [PMID: 31999492 DOI: 10.1089/gtmb.2019.0195] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Introduction: Primary distal renal tubular acidosis (dRTA) is a rare genetic disorder characterized by an impaired urinary acidification process in distal nephrons that results in the production of alkaline urine. Loss of function variants in any of the three genes, ATP6V0A4, ATP6V1B1, or SLC4A1, which all play a role in normal acidification of urine by kidneys, may lead to dRTA. Objective: This study was designed to identify genetic variants underlying dRTA in Pakistani patients using whole exome sequencing, followed by confirmatory Sanger sequencing. Materials and Methods: Patients were identified following presentation with characteristic clinical features of dRTA including vomiting, dehydration, and highly alkaline urine with metabolic acidosis during the first few days of life. Whole exome sequencing and Sanger sequencing were employed for genetic analyses of the patients. In silico analyses of the identified variants were performed using web-based bioinfomatics programs. Results: Through whole exome sequencing, we identified two splice site variants (c.2257 + 1G>A and c.722 + 5G>A) in the ATP6V0A4 gene that likely underly the disease phenotype in the two families. Multiple in silico tools predicted these variants to affect the respective splice sites supporting their likely role in pathogenesis. Conclusion: The study extends the spectrum of ATP6V0A4 variants associated with dRTA and should benefit the genetic counseling and prenatal diagnosis of the affected families.
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Affiliation(s)
- Naima Khan
- Medical Genetics Research Laboratory, Department of Biotechnology, Quaid-i-Azam University, Islamabad, Pakistan
| | - Naureen Akhtar
- Department of Pediatric Nephrology, The Children's Hospital and The Institute of Child Health, Lahore, Pakistan
| | - Fehmida Farid Khan
- Medical Genetics Research Laboratory, Department of Biotechnology, Quaid-i-Azam University, Islamabad, Pakistan
| | - Sofia Hussain
- Medical Genetics Research Laboratory, Department of Biotechnology, Quaid-i-Azam University, Islamabad, Pakistan.,Department of Zoology, PMAS Arid Agriculture University, Rawalpindi, Pakistan
| | - Muhammad Naeem
- Medical Genetics Research Laboratory, Department of Biotechnology, Quaid-i-Azam University, Islamabad, Pakistan
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Saccharomyces cerevisiae: First Steps to a Suitable Model System To Study the Function and Intracellular Transport of Human Kidney Anion Exchanger 1. mSphere 2020; 5:5/1/e00802-19. [PMID: 31996424 PMCID: PMC6992373 DOI: 10.1128/msphere.00802-19] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Distal renal tubular acidosis (dRTA) is a common kidney dysfunction characterized by impaired acid secretion via urine. Previous studies revealed that α-intercalated cells of dRTA patients express mutated forms of human kidney anion exchanger 1 (kAE1) which result in inefficient plasma membrane targeting or diminished expression levels of kAE1. However, the precise dRTA-causing processes are inadequately understood, and alternative model systems are helpful tools to address kAE1-related questions in a fast and inexpensive way. In contrast to a previous study, we successfully expressed full-length kAE1 in Saccharomyces cerevisiae. Using advanced microscopy techniques as well as different biochemical and functionality assays, plasma membrane localization and biological activity were confirmed for the heterologously expressed anion transporter. These findings represent first important steps to use the potential of yeast as a model organism for studying trafficking, activity, and degradation of kAE1 and its mutant variants in the future. Saccharomyces cerevisiae has been frequently used to study biogenesis, functionality, and intracellular transport of various renal proteins, including ion channels, solute transporters, and aquaporins. Specific mutations in genes encoding most of these renal proteins affect kidney function in such a way that various disease phenotypes ultimately occur. In this context, human kidney anion exchanger 1 (kAE1) represents an important bicarbonate/chloride exchanger which maintains the acid-base homeostasis in the human body. Malfunctions in kAE1 lead to a pathological phenotype known as distal renal tubular acidosis (dRTA). Here, we evaluated the potential of baker's yeast as a model system to investigate different cellular aspects of kAE1 physiology. For the first time, we successfully expressed yeast codon-optimized full-length versions of tagged and untagged wild-type kAE1 and demonstrated their partial localization at the yeast plasma membrane (PM). Finally, pH and chloride measurements further suggest biological activity of full-length kAE1, emphasizing the potential of S. cerevisiae as a model system for studying trafficking, activity, and/or degradation of mammalian ion channels and transporters such as kAE1 in the future. IMPORTANCE Distal renal tubular acidosis (dRTA) is a common kidney dysfunction characterized by impaired acid secretion via urine. Previous studies revealed that α-intercalated cells of dRTA patients express mutated forms of human kidney anion exchanger 1 (kAE1) which result in inefficient plasma membrane targeting or diminished expression levels of kAE1. However, the precise dRTA-causing processes are inadequately understood, and alternative model systems are helpful tools to address kAE1-related questions in a fast and inexpensive way. In contrast to a previous study, we successfully expressed full-length kAE1 in Saccharomyces cerevisiae. Using advanced microscopy techniques as well as different biochemical and functionality assays, plasma membrane localization and biological activity were confirmed for the heterologously expressed anion transporter. These findings represent first important steps to use the potential of yeast as a model organism for studying trafficking, activity, and degradation of kAE1 and its mutant variants in the future.
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18
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Nephrocalcinosis: A Review of Monogenic Causes and Insights They Provide into This Heterogeneous Condition. Int J Mol Sci 2020; 21:ijms21010369. [PMID: 31935940 PMCID: PMC6981752 DOI: 10.3390/ijms21010369] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 01/01/2020] [Accepted: 01/02/2020] [Indexed: 12/19/2022] Open
Abstract
The abnormal deposition of calcium within renal parenchyma, termed nephrocalcinosis, frequently occurs as a result of impaired renal calcium handling. It is closely associated with renal stone formation (nephrolithiasis) as elevated urinary calcium levels (hypercalciuria) are a key common pathological feature underlying these clinical presentations. Although monogenic causes of nephrocalcinosis and nephrolithiasis are rare, they account for a significant disease burden with many patients developing chronic or end-stage renal disease. Identifying underlying genetic mutations in hereditary cases of nephrocalcinosis has provided valuable insights into renal tubulopathies that include hypercalciuria within their varied phenotypes. Genotypes affecting other enzyme pathways, including vitamin D metabolism and hepatic glyoxylate metabolism, are also associated with nephrocalcinosis. As the availability of genetic testing becomes widespread, we cannot be imprecise in our approach to nephrocalcinosis. Monogenic causes of nephrocalcinosis account for a broad range of phenotypes. In cases such as Dent disease, supportive therapies are limited, and early renal replacement therapies are necessitated. In cases such as renal tubular acidosis, a good renal prognosis can be expected providing effective treatment is implemented. It is imperative we adopt a precision-medicine approach to ensure patients and their families receive prompt diagnosis, effective, tailored treatment and accurate prognostic information.
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19
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Yuan J, Huang K, Wu W, Zhang L, Dong G. A novel homozygous deletion in ATP6V0A4 causes distal renal tubular acidosis: A case report. Medicine (Baltimore) 2019; 98:e16504. [PMID: 31348261 PMCID: PMC6709018 DOI: 10.1097/md.0000000000016504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
RATIONALE Autosomal recessive distal renal tubular acidosis (dRTA) is a rare condition, most cases of which are caused by genetic mutations. Several loss-of-function mutations in the ATP6V0A4 gene have been recently reported. PATIENT CONCERNS A 2-month, 24-day-old Chinese girl presenting with vomiting and diarrhea. DIAGNOSIS dRTA was established by metabolic acidosis and hypokalemia. Mutational analysis of the ATP6V0A4 gene revealed a homozygous deletion of exons 13 and 14. The father was found to have a heterozygous loss of both exons, whereas the mother was normal. INTERVENTIONS Patient was treated with potassium citrate. OUTCOMES The patient has shown normal pH and potassium levels. LESSONS This is the first case of a homozygous deletion in ATP6V0A4 reported in the literature. Although the initial auditory screening was normal in this case, this patient will nevertheless undergo long-term auditory testing.
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20
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Lashhab R, Ullah AS, Cordat E. Renal collecting duct physiology and pathophysiology. Biochem Cell Biol 2019; 97:234-242. [DOI: 10.1139/bcb-2018-0192] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Affiliation(s)
- Rawad Lashhab
- Department of Physiology and Membrane Protein and Disease Research Group, University of Alberta, Edmonton, AB T6G 2H7, Canada
- Department of Physiology and Membrane Protein and Disease Research Group, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - A.K.M. Shahid Ullah
- Department of Physiology and Membrane Protein and Disease Research Group, University of Alberta, Edmonton, AB T6G 2H7, Canada
- Department of Physiology and Membrane Protein and Disease Research Group, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Emmanuelle Cordat
- Department of Physiology and Membrane Protein and Disease Research Group, University of Alberta, Edmonton, AB T6G 2H7, Canada
- Department of Physiology and Membrane Protein and Disease Research Group, University of Alberta, Edmonton, AB T6G 2H7, Canada
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21
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Mikhaylenko DS, Prosyannikov MY, Baranova A, Nemtsova MV. [Genetic and biochemical features of the monogenic hereditary urolithiasis]. BIOMEDIT︠S︡INSKAI︠A︡ KHIMII︠A︡ 2018; 64:315-325. [PMID: 30135278 DOI: 10.18097/pbmc20186404315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Urolithiasis is a common urological problem. In most cases, this multifactorial pathology develops due to the combination of inherited low-penetrance gene variants and environment factors such as urinary tract infections and unbalanced diet. However, some cases are monogenic. These hereditary forms of urolithiasis manifest in childhood, and are characterized by multiple, bilateral and recurrent kidney stones and progress to chronic renal failure relatively early. Due to widening acceptance of exome and gene panel sequencing, substantially larger percentages of urolithiasis cases are now attributed to hereditary causes, up to 20% among patients of 18 years old or younger. Here we review genetic and biochemical mechanisms of urolithiasis, with an emphasis on its hereditary forms, including fermentopathies (primary hyperoxaluria, adenine phosphorobosyltransferase deficiency, phosphoribosyl-pyrophosphate-synthetase deficiency, xanthinuria, Lesch-Nihan syndrome) and these caused by membrane transport alterations (Dent's disease, familial hypomagnesia with hypercalciuria and nephrocalcinosis, hypophosphatemic urolithiasis, distal tubular acidosis, cystinuria, Bartter's syndrome). We suggest a comprehensive gene panel for NGS diagnostics of the hereditary urolithiasis. It is expected that accurate and timely diagnosis of hereditary forms of urolithiasis would enable the counselling of the carriers in affected families, and ensure personalized management of the patients with these conditions.
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Affiliation(s)
- D S Mikhaylenko
- Institute of Molecular Medicine of the Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia; Lopatkin Research Institute of Urology and Interventional Radiology - branch of the National Medical Research Center of Radiology, Moscow, Russia; Research Centre for Medical Genetics, Moscow, Russia
| | - M Y Prosyannikov
- Lopatkin Research Institute of Urology and Interventional Radiology - branch of the National Medical Research Center of Radiology, Moscow, Russia
| | - A Baranova
- Center for the Study of Chronic Metabolic and Rare Diseases, George Mason University, Fairfax, Virginia, USA
| | - M V Nemtsova
- Institute of Molecular Medicine of the Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia; Research Centre for Medical Genetics, Moscow, Russia
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