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Talukder MH, Takajo D, Kakkerala S, Kumar B. Case 2: Poor Weight Gain in a 9-month-old Girl. Pediatr Rev 2024; 45:333-337. [PMID: 38821892 DOI: 10.1542/pir.2022-005524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 07/11/2022] [Accepted: 07/12/2022] [Indexed: 06/02/2024]
Affiliation(s)
| | - Daiji Takajo
- Department of Pediatrics, Children's Hospital of Michigan, Detroit, MI
| | - Sushma Kakkerala
- Department of Pediatrics, Children's Hospital of Michigan, Detroit, MI
- Pediatric Hospitalists, Children's Hospital of Michigan, Central Michigan University, Mt Pleasant, MI
| | - Banu Kumar
- Department of Pediatrics, Children's Hospital of Michigan, Detroit, MI
- Pediatric Hospitalists, Children's Hospital of Michigan, Central Michigan University, Mt Pleasant, MI
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Yan X, Hu Y, Zhang X, Gao X, Zhao Y, Peng H, Ouyang L, Zhang C. Identification of a novel intronic mutation of MAGED2 gene in a Chinese family with antenatal Bartter syndrome. BMC Med Genomics 2024; 17:23. [PMID: 38238844 PMCID: PMC10795325 DOI: 10.1186/s12920-024-01797-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Accepted: 01/05/2024] [Indexed: 01/22/2024] Open
Abstract
BACKGROUND Antenatal Bartter syndrome is a life-threatening disease caused by a mutation in the MAGED2 gene located on chromosome Xp11. It is characterized by severe polyhydramnios and extreme prematurity. While most reported mutations are located in the exon region, variations in the intron region are rarely reported. METHODS In our study, we employed whole exome sequencing and Sanger sequencing to genotype members of this family. Additionally, a minigene assay was conducted to evaluate the impact of genetic variants on splicing. RESULTS Our findings reveal a novel intronic variant (NM_177433.3:c.1271 + 4_1271 + 7delAGTA) in intron 10 of the MAGED2 gene. Further analysis using the minigene assay demonstrated that this variant activated an intronic cryptic splice site, resulting in a 96 bp insertion in mature mRNA. CONCLUSIONS Our results indicate that the novel intronic variant (c.1271 + 4_1271 + 7delAGTA) in intron 10 of the MAGED2 gene is pathogenic. This expands the mutation spectrum of MAGED2 and highlights the significance of intronic sequence analysis.
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Affiliation(s)
- Xu Yan
- Reproductive Medicine Center, Renmin Hospital, Hubei University of Medicine, Shiyan, 442000, China
- Biomedical Engineering College, Hubei University of Medicine, Shiyan, 442000, China
- Hubei Clinical Research Center for Reproductive Medicine, Shiyan, China
- Hubei Key Laboratory of Embryonic Stem Cell Research, Hubei University of Medicine, Shiyan, China
| | - Yueyue Hu
- Reproductive Medicine Center, Renmin Hospital, Hubei University of Medicine, Shiyan, 442000, China
| | - Xin Zhang
- Reproductive Medicine Center, Renmin Hospital, Hubei University of Medicine, Shiyan, 442000, China
| | - Xia Gao
- Obstetrics, Renmin Hospital, Hubei University of Medicine, Shiyan, 442000, China
| | - Yang Zhao
- Neonatal Intensive Care, Renmin Hospital, Hubei University of Medicine, Shiyan, 442000, China
| | - Haiying Peng
- Reproductive Medicine Center, Renmin Hospital, Hubei University of Medicine, Shiyan, 442000, China
- Biomedical Engineering College, Hubei University of Medicine, Shiyan, 442000, China
| | - Liu Ouyang
- Obstetrics, Renmin Hospital, Hubei University of Medicine, Shiyan, 442000, China
| | - Changjun Zhang
- Reproductive Medicine Center, Renmin Hospital, Hubei University of Medicine, Shiyan, 442000, China.
- Biomedical Engineering College, Hubei University of Medicine, Shiyan, 442000, China.
- Hubei Clinical Research Center for Reproductive Medicine, Shiyan, China.
- Hubei Key Laboratory of Embryonic Stem Cell Research, Hubei University of Medicine, Shiyan, China.
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Yaprak D, Kara H, Calisici E, Karagöl BS, Altan M. A novel homozygous CLCNKB variant: An early presentation of classic Bartter syndrome in a neonate. Birth Defects Res 2023; 115:1674-1679. [PMID: 37587715 DOI: 10.1002/bdr2.2235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2023] [Revised: 06/21/2023] [Accepted: 07/24/2023] [Indexed: 08/18/2023]
Abstract
BACKGROUND Bartter syndrome (BS) is a rare congenital salt-losing renal tubular transport disorder, characterized by salt wasting, polyuria, biochemical abnormalities, and acid-base homeostasis imbalance. The syndrome has five different genetic forms, and novel mutations of CLCNKB gene lead to type 3 BS also known as classic BS. In this case, we report clinical and molecular findings from a newborn baby with BS. CASE A 10-day-old male infant born at 37 weeks of gestation by cesarean section following a pregnancy complicated with polyhydramnios, and fetal distress to a 30-year-old gravida 3, para 3 mother, with a 2500 g birth weight was brought to the pediatric emergency department due to weight loss and jaundice. The neonate was referred to the neonatal intensive care unit (NICU) with a preliminary diagnosis of hyponatremic dehydration (Na: 122 mmol/L, 10% dehydration) and hypokalemic hypochloremic metabolic alkalosis (K: 2.13 mmol/L, Cl: 63 mmol/L, pH: 7.62, pCO2 : 39 mmHg, HCO3 : 40.8 mmol/L, BE: 16.9 mmol/L), and hypocalcemia (ionized Ca: 0.72 mmol/L). On arrival to the NICU, symptomatic focal seizures, and polyuria complicated his course. Spot urine biochemistry revealed a renal salt wasting and hypercalciuria: Creatine 11.4 mg/dL Na: 51 mmol/L (54-150), K: 26 mmol/L (20-80), Cl: 164 mmol/L, fractional excretion of sodium (FENa): 3% (0.9-1.6), fractional excretion of chloride (FECl): 17% (<0.5%) and Ca/Cr: 0.33 (<0.2). Biochemical abnormalities disappeared through intravenous fluid and electrolyte therapy, but he could not achieve adequate weight gain, and polyuric urine output (6.5 cc/kg/h), and metabolic alkalosis continued as the enteral feedings advance. Patient's serum renin: 184 pg/mL (5-27 pg/mL) and aldosterone: 1670 pg/mL (1-180 ng/dL) were elevated. Polyuria, renal salt wasting, electrolyte and acid-base disturbances, and hyperreninemic hyperaldosteronism established the diagnosis as Bartter syndrome. An oral indomethacin (1 mg/kg/day) treatment, on the 8th day. ensured the weight gain, and normalized daily urine output. He achieved the goal of birth weight on the 30th day and he was 3520 g weight at discharge on day 42. The genetic tests of the patient as KCNJ1 SLC12A1 gene sequence analysis revealed a novel homozygous mutation in the 14th exon of the CLCNKB gene, the c.1334_1338del CTTTT (p. Ser445fs*4) variant was identified. DISCUSSION The diagnosis of BS should be considered in the presence of a medical history of severe polyhydramnios of fetal origin. Postnatally, polyuria, signs of dehydration, renal salt wasting, and hypokalemic-metabolic alkalosis should prompt the clinician to request genetic testing for BS in the neonatal period. This case is presented to emphasize that early diagnosis of BS should be considered in newborns presenting with electrolyte abnormalities and metabolic alkalosis accompanying dehydration and favorable growth results can be achieved by starting indomethacin treatment in the early neonatal period. The clinical exome sequencing illustrated a novel missense variant in the CLCNKB gene leading to the molecular diagnosis of BS type 3.
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Affiliation(s)
- Deniz Yaprak
- Gulhane Medicine Faculty, Department of Pediatrics, Division of Neonatology, University of Health Sciences, Ankara, Turkey
| | - Hüdaverdi Kara
- Gulhane Medicine Faculty, Department of Pediatrics, University of Health Sciences, Ankara, Turkey
| | - Erhan Calisici
- Gulhane Medicine Faculty, Department of Pediatrics, Division of Neonatology, University of Health Sciences, Ankara, Turkey
| | - Belma Saygılı Karagöl
- Gulhane Medicine Faculty, Department of Pediatrics, Division of Neonatology, University of Health Sciences, Ankara, Turkey
| | - Mustafa Altan
- Ankara Bilkent City Hospital, Department of Medical Genetics, University of Health Sciences, Ankara, Turkey
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Janchevska A, Tasic V, Jordanova O, Gucev Z, Jenkins L, Jovanovska N, Plaseska-Karanfilska D, Ashton E, Bockenhauer D. Two Brothers from Macedonia with Gitelman Syndrome. Balkan J Med Genet 2023; 26:69-74. [PMID: 37576796 PMCID: PMC10413880 DOI: 10.2478/bjmg-2023-0009] [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] [Indexed: 08/15/2023] Open
Abstract
Gitelman syndrome (GS) is a rare renal tubulopathy with an autosomal recessive mode of inheritance, caused by biallelic pathogenic variants in the SLC12A3 gene. The clinical features may overlap with other disorders, such as Bartter syndrome type 3, HNF1B nephropathy or even mitochondrial disease, but can be distinguished by molecular genetic analysis. Here we report on two preschool brothers, who presented with a several months' history of episodes of carpopedal spasms and muscle aches. The biochemical analyses revealed hypokalemia and hypomagnesemia without metabolic alkalosis. A 24-h urine sample demonstrated hypocalciuria. The molecular analyses showed that both patients were heterozygous for 3 (likely) pathogenic variants in SLC12A3: c.1805_1806del; p. (Tyr602Cysfs*31), c.2660+1G>A and c.2944 A>T; p. (Ile982Phe). Analysis of the parents showed that the mother was heterozygous for the c.2944 A>T p.(Ile982Phe) variant, and the father carried the other 2 variants (c.1805_1806del and c.2660+1G>A). Herein we present two children in a family from N. Macedonia with clinical manifestations and electrolyte imbalances suggestive of GS. The results of the tubulopathy next generation sequencing (NGS) panel confirmed the diagnosis. The boys are treated with a high salt diet and oral potassium and magnesium supplements.
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Affiliation(s)
- A Janchevska
- University Children’s hospital, Skopje, Rep. of N. Macedonia
| | - V Tasic
- University Children’s hospital, Skopje, Rep. of N. Macedonia
| | - O Jordanova
- University Children’s hospital, Skopje, Rep. of N. Macedonia
| | - Z Gucev
- University Children’s hospital, Skopje, Rep. of N. Macedonia
| | - L Jenkins
- North East Thames Regional Genetic Laboratory, Great Ormond Street Hospital for children, London, UK
| | - N Jovanovska
- Research Center for Genetic Engineering and Biotechnology “Georgi D Efremov”, Macedonian Academy of Sciences and Arts, Skopje, Rep. of N. Macedonia
| | - D Plaseska-Karanfilska
- Research Center for Genetic Engineering and Biotechnology “Georgi D Efremov”, Macedonian Academy of Sciences and Arts, Skopje, Rep. of N. Macedonia
| | - E Ashton
- North East Thames Regional Genetic Laboratory, Great Ormond Street Hospital for children, London, UK
| | - D Bockenhauer
- North East Thames Regional Genetic Laboratory, Great Ormond Street Hospital for children, London, UK
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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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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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Wan ER, Iancu D, Ashton E, Siew K, Mohidin B, Sung CC, Nagano C, Bockenhauer D, Lin SH, Nozu K, Walsh SB. Machine Learning to Identify Genetic Salt-Losing Tubulopathies in Hypokalemic Patients. Kidney Int Rep 2023; 8:556-565. [PMID: 36938092 PMCID: PMC10014379 DOI: 10.1016/j.ekir.2022.12.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 11/29/2022] [Accepted: 12/12/2022] [Indexed: 12/25/2022] Open
Abstract
Introduction Clinically distinguishing patients with the inherited salt-losing tubulopathies (SLTs), Gitelman or Bartter syndrome (GS or BS) from other causes of hypokalemia (LK) patients is difficult, and genotyping is costly. We decided to identify clinical characteristics that differentiate SLTs from LK. Methods A total of 66 hypokalemic patients with possible SLTs were recruited to a prospective observational cohort study at the University College London Renal Tubular Clinic, London. All patients were genotyped for pathogenic variants in genes which cause SLTs; 39 patients had pathogenic variants in genes causing SLTs. We obtained similar data sets from cohorts in Taipei and Kobe, as follows: the combined data set comprised 419 patients; 291 had genetically confirmed SLT. London and Taipei data sets were combined to train machine learning (ML) algorithms, which were then tested on the Kobe data set. Results Single biochemical variables (e.g., plasma renin) were significantly, but inconsistently, different between SLTs and LK in all cohorts. A decision table algorithm using serum bicarbonate and urinary sodium excretion (FENa) achieved a classification accuracy of 74%. This was superior to all the single biochemical variables identified previously. Conclusion ML algorithms can differentiate true SLT in the context of a specialist clinic with some accuracy. However, based on routine biochemistry, the accuracy is insufficient to make genotyping redundant.
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Affiliation(s)
- Elizabeth R. Wan
- Department of Renal Medicine, University College London, London, UK
| | - Daniela Iancu
- Department of Renal Medicine, University College London, London, UK
| | - Emma Ashton
- North East Thames Regional Genetics Service Laboratories, Great Ormond Street Hospital for Children National Health Service Foundation Trust, London, UK
| | - Keith Siew
- Department of Renal Medicine, University College London, London, UK
| | - Barian Mohidin
- Department of Renal Medicine, University College London, London, UK
| | - Chih-Chien Sung
- Division of Nephrology, Department of Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - China Nagano
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Detlef Bockenhauer
- Department of Renal Medicine, University College London, London, UK
- Department of Pediatric Nephrology, Great Ormond Street Hospital for Children National Health Service Foundation Trust, London, UK
| | - Shih-Hua Lin
- Division of Nephrology, Department of Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Kandai Nozu
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Stephen B. Walsh
- Department of Renal Medicine, University College London, London, UK
- Correspondence: Stephen B. Walsh, Department of Renal Medicine, University College London, 1st Floor Medical School, Royal Free Hospital, Rowland Hill Street, Hampstead, London, NW3 2PF, UK.
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Kermond R, Mallett A, McCarthy H. A clinical approach to tubulopathies in children and young adults. Pediatr Nephrol 2023; 38:651-662. [PMID: 35585366 PMCID: PMC9842573 DOI: 10.1007/s00467-022-05606-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 04/27/2022] [Accepted: 04/28/2022] [Indexed: 01/21/2023]
Abstract
Kidney tubules are responsible for the preservation of fluid, electrolyte and acid-base homeostasis via passive and active mechanisms. These physiological processes can be disrupted by inherited or acquired aetiologies. The net result is a tubulopathy. It is important to make a prompt and accurate diagnosis of tubulopathies in children and young adults. This allows timely and appropriate management, including disease-specific therapies, and avoids complications such as growth failure. Tubulopathies can present with a variety of non-specific clinical features which can be diagnostically challenging. In this review, we build from this common anatomical and physiological understanding to present a tangible appreciation of tubulopathies as they are likely to be clinically encountered among affected children and young adults.
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Affiliation(s)
- Rachael Kermond
- Department of Renal Medicine, Sydney Children’s Hospital Network, Sydney, NSW Australia
| | - Andrew Mallett
- Department of Renal Medicine, Townsville University Hospital, Douglas, QLD, Australia. .,College of Medicine and Dentistry, James Cook University, Douglas, QLD, Australia. .,Institute for Molecular Bioscience & Faculty of Medicine, The University of Queensland, Brisbane, QLD, Australia.
| | - Hugh McCarthy
- Department of Renal Medicine, Sydney Children's Hospital Network, Sydney, NSW, Australia. .,Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia. .,Centre for Kidney Research, The Children's Hospital at Westmead, Sydney, New South Wales, Australia.
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Choi N, Kang HG. Bartter Syndrome: Perspectives of a Pediatric Nephrologist. Electrolyte Blood Press 2022; 20:49-56. [PMID: 36688207 PMCID: PMC9827044 DOI: 10.5049/ebp.2022.20.2.49] [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: 10/20/2022] [Revised: 11/25/2022] [Accepted: 12/06/2022] [Indexed: 01/05/2023] Open
Abstract
Bartter syndrome (BS) is one of the most well-known hereditary tubular disorders, characterized by hypokalemic, hypochloremic metabolic alkalosis, and polyuria/polydipsia. This disease usually presents before or during infancy, and adult nephrologists often inherit the patients from pediatric nephrologists since this is a life-long condition. Here, a few case scenarios will be presented to recount how they first got diagnosed and how their clinical courses were during childhood until adulthood, in addition to a brief review of the disease and its treatment.
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Affiliation(s)
- Naye Choi
- Department of Pediatrics, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Hee Gyung Kang
- Department of Pediatrics, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Republic of Korea
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Yıldız G, Torun Bayram M, Çinleti T, Koç A, Soylu A, Kavukçu S. Late onset Bartter syndrome: Bartter syndrome type 2 presenting with isolated nephrocalcinosis and high parathyroid hormone levels mimicking primary hyperparathyroidism. J Pediatr Endocrinol Metab 2022; 35:1298-1301. [PMID: 35952717 DOI: 10.1515/jpem-2022-0154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Accepted: 07/24/2022] [Indexed: 11/15/2022]
Abstract
OBJECTIVES Nephrocalcinosis is associated with conditions that cause hypercalcemia and the increased urinary excretion of calcium, phosphate, and/or oxalate. A monogenic etiology is found in almost 30% of childhood-onset nephrocalcinosis which is also a common manifestation of primary hyperparathyroidism. We discuss a child with nephrocalcinosis and features mimicking primary hyperparathyroidism. CASE PRESENTATION A 7-year-old girl presented with nephrocalcinosis. Hypercalciuria, hyperphosphaturia, mild hypercalcemia, hypophosphatemia and elevated parathyroid hormone levels along with normal serum creatinine and absence of hypokalemic alkalosis suggested primary hyperparathyroidism. However, she was ultimately diagnosed with Bartter syndrome type 2 based on the presence of homozygous pathogenic variation in KCNJ1gene. CONCLUSIONS This is the second reported case of late-onset Bartter syndrome type 2 without hypokalemic alkalosis. Patients with Bartter syndrome may present with high parathyroid hormone levels and hypercalcemia in addition to hypercalciuria. Thus, the present case suggests that the KCNJ1 gene should be included in genetic analysis even in older children with isolated nephrocalcinosis.
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Affiliation(s)
- Gizem Yıldız
- Department of Pediatric Nephrology, Dokuz Eylül University Medical Faculty, Izmir, Turkey
| | - Meral Torun Bayram
- Department of Pediatric Nephrology, Dokuz Eylül University Medical Faculty, Izmir, Turkey
| | - Tayfun Çinleti
- Department of Pediatric Genetic, Dokuz Eylül University Medical Faculty, Izmir, Turkey
| | - Altuğ Koç
- Department of Medical Genetics, Dokuz Eylül University Medical Faculty, Izmir, Turkey
| | - Alper Soylu
- Department of Pediatric Nephrology and Rheumatology, Dokuz Eylül University Medical Faculty, Izmir, Turkey
| | - Salih Kavukçu
- Department of Pediatric Nephrology and Rheumatology, Dokuz Eylül University Medical Faculty, Izmir, Turkey
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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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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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13
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Clinical and Genetic Characterization of Patients with Bartter and Gitelman Syndrome. Int J Mol Sci 2022; 23:ijms23105641. [PMID: 35628451 PMCID: PMC9144947 DOI: 10.3390/ijms23105641] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 05/09/2022] [Accepted: 05/13/2022] [Indexed: 02/04/2023] Open
Abstract
Bartter (BS) and Gitelman (GS) syndrome are autosomal recessive inherited tubulopathies, whose clinical diagnosis can be challenging, due to rarity and phenotypic overlap. Genotype-phenotype correlations have important implications in defining kidney and global outcomes. The aim of our study was to assess the diagnostic rate of whole-exome sequencing (WES) coupled with a bioinformatic analysis of copy number variations in a population of 63 patients with BS and GS from a single institution, and to explore genotype-phenotype correlations. We obtained a diagnostic yield of 86% (54/63 patients), allowing disease reclassification in about 14% of patients. Although some clinical and laboratory features were more commonly reported in patients with BS or GS, a significant overlap does exist, and age at onset, preterm birth, gestational age and nephro-calcinosis are frequently misleading. Finally, chronic kidney disease (CKD) occurs in about 30% of patients with BS or GS, suggesting that the long-term prognosis can be unfavorable. In our cohort the features associated with CKD were lower gestational age at birth and a molecular diagnosis of BS, especially BS type 1. The results of our study demonstrate that WES is useful in dealing with the phenotypic heterogeneity of these disorders, improving differential diagnosis and genotype-phenotype correlation.
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14
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Alhasan K, D'Alessandri-Silva C, Mongia A, Topaloglu R, Tasic V, Filler G. Young Adults With Hereditary Tubular Diseases: Practical Aspects for Adult-Focused Colleagues. Adv Chronic Kidney Dis 2022; 29:292-307. [PMID: 36084976 DOI: 10.1053/j.ackd.2021.11.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 11/07/2021] [Accepted: 11/15/2021] [Indexed: 11/11/2022]
Abstract
Recent advances in the management of kidney tubular diseases have resulted in a significant cohort of adolescents and young adults transitioning from pediatric- to adult-focused care. Most of the patients under adult-focused care have glomerular diseases, whereas rarer tubular diseases form a considerable proportion of pediatric patients. The purpose of this review is to highlight the clinical signs and symptoms of tubular disorders, as well as their diagnostic workup, including laboratory findings and imaging, during young adulthood. We will then discuss more common disorders such as cystinosis, cystinuria, distal kidney tubular acidosis, congenital nephrogenic diabetes insipidus, Dent disease, rickets, hypercalciuria, and syndromes such as Bartter, Fanconi, Gitelman, Liddle, and Lowe. This review is a practical guide on the diagnostic and therapeutic approach of tubular conditions affecting young adults who are transitioning to adult-focused care.
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Affiliation(s)
- Khalid Alhasan
- Department of Pediatrics, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Cynthia D'Alessandri-Silva
- Department of Pediatrics, University of Connecticut School of Medicine, Farmington, and Nephrology, Connecticut Children's Medical Center, Hartford, CT
| | - Anil Mongia
- Department of Pediatrics, SUNY Downstate Medical Center, Brooklyn, NY
| | - Rezan Topaloglu
- Department of Paediatrics, Division of Pediatric Nephrology, Hacettepe University School of Medicine, Ankara, Turkey
| | - Velibor Tasic
- University Children's Hospital, Medical School, Skopje, North Macedonia
| | - Guido Filler
- Department of Paediatrics, Division of Pediatric Nephrology, Western University, London, ON, Canada; Department of Medicine, Western University, London, ON, Canada; Department of Pathology and Laboratory Medicine, Western University, London, ON, Canada.
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15
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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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16
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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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17
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Agarwal S, Sudhini YR, Polat OK, Reiser J, Altintas MM. Renal cell markers: lighthouses for managing renal diseases. Am J Physiol Renal Physiol 2021; 321:F715-F739. [PMID: 34632812 DOI: 10.1152/ajprenal.00182.2021] [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] [Indexed: 12/13/2022] Open
Abstract
Kidneys, one of the vital organs in our body, are responsible for maintaining whole body homeostasis. The complexity of renal function (e.g., filtration, reabsorption, fluid and electrolyte regulation, and urine production) demands diversity not only at the level of cell types but also in their overall distribution and structural framework within the kidney. To gain an in depth molecular-level understanding of the renal system, it is imperative to discern the components of kidney and the types of cells residing in each of the subregions. Recent developments in labeling, tracing, and imaging techniques have enabled us to mark, monitor, and identify these cells in vivo with high efficiency in a minimally invasive manner. In this review, we summarize different cell types, specific markers that are uniquely associated with those cell types, and their distribution in the kidney, which altogether make kidneys so special and different. Cellular sorting based on the presence of certain proteins on the cell surface allowed for the assignment of multiple markers for each cell type. However, different studies using different techniques have found contradictions in cell type-specific markers. Thus, the term "cell marker" might be imprecise and suboptimal, leading to uncertainty when interpreting the data. Therefore, we strongly believe that there is an unmet need to define the best cell markers for a cell type. Although the compendium of renal-selective marker proteins presented in this review is a resource that may be useful to researchers, we acknowledge that the list may not be necessarily exhaustive.
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Affiliation(s)
- Shivangi Agarwal
- Department of Internal Medicine, Rush University, Chicago, Illinois
| | | | - Onur K Polat
- Department of Internal Medicine, Rush University, Chicago, Illinois
| | - Jochen Reiser
- Department of Internal Medicine, Rush University, Chicago, Illinois
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18
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Schlingmann KP, Jouret F, Shen K, Nigam A, Arjona FJ, Dafinger C, Houillier P, Jones DP, Kleinerüschkamp F, Oh J, Godefroid N, Eltan M, Güran T, Burtey S, Parotte MC, König J, Braun A, Bos C, Ibars Serra M, Rehmann H, Zwartkruis FJ, Renkema KY, Klingel K, Schulze-Bahr E, Schermer B, Bergmann C, Altmüller J, Thiele H, Beck BB, Dahan K, Sabatini D, Liebau MC, Vargas-Poussou R, Knoers NV, Konrad M, de Baaij JH. mTOR-Activating Mutations in RRAGD Are Causative for Kidney Tubulopathy and Cardiomyopathy. J Am Soc Nephrol 2021; 32:2885-2899. [PMID: 34607910 PMCID: PMC8806087 DOI: 10.1681/asn.2021030333] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 07/07/2021] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Over the last decade, advances in genetic techniques have resulted in the identification of rare hereditary disorders of renal magnesium and salt handling. Nevertheless, approximately 20% of all patients with tubulopathy lack a genetic diagnosis. METHODS We performed whole-exome and -genome sequencing of a patient cohort with a novel, inherited, salt-losing tubulopathy; hypomagnesemia; and dilated cardiomyopathy. We also conducted subsequent in vitro functional analyses of identified variants of RRAGD, a gene that encodes a small Rag guanosine triphosphatase (GTPase). RESULTS In eight children from unrelated families with a tubulopathy characterized by hypomagnesemia, hypokalemia, salt wasting, and nephrocalcinosis, we identified heterozygous missense variants in RRAGD that mostly occurred de novo. Six of these patients also had dilated cardiomyopathy and three underwent heart transplantation. We identified a heterozygous variant in RRAGD that segregated with the phenotype in eight members of a large family with similar kidney manifestations. The GTPase RagD, encoded by RRAGD, plays a role in mediating amino acid signaling to the mechanistic target of rapamycin complex 1 (mTORC1). RagD expression along the mammalian nephron included the thick ascending limb and the distal convoluted tubule. The identified RRAGD variants were shown to induce a constitutive activation of mTOR signaling in vitro. CONCLUSIONS Our findings establish a novel disease, which we call autosomal dominant kidney hypomagnesemia (ADKH-RRAGD), that combines an electrolyte-losing tubulopathy and dilated cardiomyopathy. The condition is caused by variants in the RRAGD gene, which encodes Rag GTPase D; these variants lead to an activation of mTOR signaling, suggesting a critical role of Rag GTPase D for renal electrolyte handling and cardiac function.
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Affiliation(s)
- Karl P. Schlingmann
- Department of General Pediatrics, University Children’s Hospital, Münster, Germany
| | - François Jouret
- Division of Nephrology, Department of Internal Medicine, University of Liège Hospital, Liège, Belgium,Interdisciplinary Group of Applied Genoproteomics, Cardiovascular Sciences, University of Liège, Liège, Belgium
| | - Kuang Shen
- Whitehead Institute for Biomedical Research, Cambridge, Massachusetts,Department of Biology, Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, Massachusetts,Koch Institute for Integrative Cancer Research, Cambridge, Massachusetts,Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts,Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts
| | - Anukrati Nigam
- Department of Genetics, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Francisco J. Arjona
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Claudia Dafinger
- Department of Pediatrics and Center for Molecular Medicine Cologne, Faculty of Medicine, University of Cologne and University Hospital Cologne, Cologne, Germany,Department II of Internal Medicine and Center for Molecular Medicine Cologne, Faculty of Medicine, University of Cologne and University Hospital Cologne, Cologne, Germany
| | - Pascal Houillier
- Cordeliers Research Center, Centre National de la Recherche Scientifique (CNRS), ERL8228, Institut National de la Santé et de la Recherche Médicale (INSERM), Sorbonne University, University of Paris, Paris, France,Department of Physiology, Assistance Publique-Hôpitaux de Paris (AP-HP), European Hospital Georges Pompidou, Paris, France,Reference Center for Hereditary Renal Diseases in Children and Adults (MARHEA), Paris, France
| | - Deborah P. Jones
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Felix Kleinerüschkamp
- Department of Pediatric Cardiology, University Children’s Hospital, Münster, Germany
| | - Jun Oh
- Department of Pediatrics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Nathalie Godefroid
- Division of Pediatric Nephrology, Saint-Luc University Clinics, Catholic University of Louvain, Brussels, Belgium
| | - Mehmet Eltan
- Department of Pediatric Endocrinology and Diabetes, School of Medicine, Marmara University, Istanbul, Turkey
| | - Tülay Güran
- Department of Pediatric Endocrinology and Diabetes, School of Medicine, Marmara University, Istanbul, Turkey
| | - Stéphane Burtey
- Center for Nephrology and Renal Transplantation, Assistance Publique-Hôpitaux de Marseille, Aix-Marseille University, Marseille, France
| | - Marie-Christine Parotte
- Division of Nephrology-Dialysis, Department of Internal Medicine, CHR Verviers East Belgium, Verviers, Belgium
| | - Jens König
- Department of General Pediatrics, University Children’s Hospital, Münster, Germany
| | - Alina Braun
- Department of Pediatrics and Center for Molecular Medicine Cologne, Faculty of Medicine, University of Cologne and University Hospital Cologne, Cologne, Germany,Department II of Internal Medicine and Center for Molecular Medicine Cologne, Faculty of Medicine, University of Cologne and University Hospital Cologne, Cologne, Germany
| | - Caro Bos
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Maria Ibars Serra
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Holger Rehmann
- Department of Molecular Cancer Research, Center for Molecular Medicine, Oncode Institute, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Fried J.T. Zwartkruis
- Department of Molecular Cancer Research, Center for Molecular Medicine, Oncode Institute, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Kirsten Y. Renkema
- Department of Genetics, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Karin Klingel
- Cardiopathology, Institute for Pathology and Neuropathology, University Hospital Tübingen, Tübingen, Germany
| | - Eric Schulze-Bahr
- Institute for Genetics of Heart Diseases (IfGH), Department of Cardiovascular Medicine, University Hospital Münster, Münster, Germany
| | - Bernhard Schermer
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, Faculty of Medicine, University of Cologne and University Hospital Cologne, Cologne, Germany,CECAD, Faculty of Medicine, University of Cologne and University Hospital Cologne, Cologne, Germany
| | - Carsten Bergmann
- Limbach Genetics, Medizinische Genetik Mainz, Mainz, Germany,Division of Nephrology, Department of Medicine, University Hospital Freiburg, Breisgau, Germany
| | - Janine Altmüller
- Cologne Center for Genomics, University of Cologne, Cologne, Germany
| | - Holger Thiele
- Cologne Center for Genomics, University of Cologne, Cologne, Germany
| | - Bodo B. Beck
- Institute of Human Genetics, University Hospital Cologne and University of Cologne, Faculty of Medicine, Cologne, Germany,Center for Molecular Medicine Cologne, University of Cologne, Faculty of Medicine, University Hospital Cologne, Cologne, Germany,Center for Rare Diseases, Medical Faculty, University of Cologne and University Hospital Cologne, Cologne, Germany
| | - Karin Dahan
- Center of Human Genetics, Gosselies, Belgium,Division of Nephrology, Saint-Luc University Clinics, Catholic University of Louvain, Brussels, Belgium
| | - David Sabatini
- Whitehead Institute for Biomedical Research, Cambridge, Massachusetts,Department of Biology, Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, Massachusetts,Koch Institute for Integrative Cancer Research, Cambridge, Massachusetts,Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Max C. Liebau
- Department of Pediatrics and Center for Molecular Medicine Cologne, Faculty of Medicine, University of Cologne and University Hospital Cologne, Cologne, Germany,Department II of Internal Medicine and Center for Molecular Medicine Cologne, Faculty of Medicine, University of Cologne and University Hospital Cologne, Cologne, Germany,Center for Rare Diseases, Medical Faculty, University of Cologne and University Hospital Cologne, Cologne, Germany
| | - Rosa Vargas-Poussou
- Department of Genetics, AP-HP, European Hospital Georges Pompidou, Paris, France
| | - Nine V.A.M. Knoers
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Martin Konrad
- 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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19
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Nuñez-Gonzalez L, Carrera N, Garcia-Gonzalez MA. Molecular Basis, Diagnostic Challenges and Therapeutic Approaches of Bartter and Gitelman Syndromes: A Primer for Clinicians. Int J Mol Sci 2021; 22:11414. [PMID: 34768847 PMCID: PMC8584233 DOI: 10.3390/ijms222111414] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 10/13/2021] [Accepted: 10/14/2021] [Indexed: 12/18/2022] Open
Abstract
Gitelman and Bartter syndromes are rare inherited diseases that belong to the category of renal tubulopathies. The genes associated with these pathologies encode electrolyte transport proteins located in the nephron, particularly in the Distal Convoluted Tubule and Ascending Loop of Henle. Therefore, both syndromes are characterized by alterations in the secretion and reabsorption processes that occur in these regions. Patients suffer from deficiencies in the concentration of electrolytes in the blood and urine, which leads to different systemic consequences related to these salt-wasting processes. The main clinical features of both syndromes are hypokalemia, hypochloremia, metabolic alkalosis, hyperreninemia and hyperaldosteronism. Despite having a different molecular etiology, Gitelman and Bartter syndromes share a relevant number of clinical symptoms, and they have similar therapeutic approaches. The main basis of their treatment consists of electrolytes supplements accompanied by dietary changes. Specifically for Bartter syndrome, the use of non-steroidal anti-inflammatory drugs is also strongly supported. This review aims to address the latest diagnostic challenges and therapeutic approaches, as well as relevant recent research on the biology of the proteins involved in disease. Finally, we highlight several objectives to continue advancing in the characterization of both etiologies.
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Affiliation(s)
- Laura Nuñez-Gonzalez
- Grupo de Xenetica e Bioloxia do Desenvolvemento das Enfermidades Renais, Laboratorio de Nefroloxia (No. 11), Instituto de Investigacion Sanitaria de Santiago (IDIS), Complexo Hospitalario de Santiago de Compostela (CHUS), 15706 Santiago de Compostela, Spain;
- Grupo de Medicina Xenomica, Complexo Hospitalario de Santiago de Compostela (CHUS), 15706 Santiago de Compostela, Spain
| | - Noa Carrera
- Grupo de Xenetica e Bioloxia do Desenvolvemento das Enfermidades Renais, Laboratorio de Nefroloxia (No. 11), Instituto de Investigacion Sanitaria de Santiago (IDIS), Complexo Hospitalario de Santiago de Compostela (CHUS), 15706 Santiago de Compostela, Spain;
- Grupo de Medicina Xenomica, Complexo Hospitalario de Santiago de Compostela (CHUS), 15706 Santiago de Compostela, Spain
- RedInRen (Red en Investigación Renal) RETIC (Redes Temáticas de Investigación Cooperativa en Salud), ISCIII (Instituto de Salud Carlos III), 28029 Madrid, Spain
| | - Miguel A. Garcia-Gonzalez
- Grupo de Xenetica e Bioloxia do Desenvolvemento das Enfermidades Renais, Laboratorio de Nefroloxia (No. 11), Instituto de Investigacion Sanitaria de Santiago (IDIS), Complexo Hospitalario de Santiago de Compostela (CHUS), 15706 Santiago de Compostela, Spain;
- Grupo de Medicina Xenomica, Complexo Hospitalario de Santiago de Compostela (CHUS), 15706 Santiago de Compostela, Spain
- RedInRen (Red en Investigación Renal) RETIC (Redes Temáticas de Investigación Cooperativa en Salud), ISCIII (Instituto de Salud Carlos III), 28029 Madrid, Spain
- Fundación Pública Galega de Medicina Xenomica—SERGAS, Complexo Hospitalario de Santiago de Compotela (CHUS), 15706 Santiago de Compostela, Spain
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Iio K, Mori T, Bessho S, Imai Y, Hatanaka M, Omori H, Kouhara H, Chiga M, Sohara E, Uchida S, Kaimori JY. Gitelman syndrome with a novel frameshift variant in SLC12A3 gene accompanied by chronic kidney disease and type 2 diabetes mellitus. CEN Case Rep 2021; 11:191-195. [PMID: 34617250 DOI: 10.1007/s13730-021-00652-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 09/28/2021] [Indexed: 11/28/2022] Open
Abstract
Gitelman syndrome is an autosomal recessive genetic disease caused by pathogenic variants in SLC12A3 resulting in the loss of function of the Na-Cl co-transporter (NCC) in the distal tubules. Hypokalemia and diuretic effects can cause secondary type 2 diabetes and renal function decline. Here, we present the case of a 49-year-old male patient with chronic persistent treatment-resistant hypokalemia for the past 13 years who had been receiving treatment for type 2 diabetes mellitus for 6 years. He was referred to our department due to the presence of urinary protein, impaired renal function, high renin activity, and hyperaldosteronism. Laboratory test results showed hypokalemia, hypomagnesemia, hypocalciuria, and metabolic alkalosis. Using next-generation and Sanger sequencing, we identified a novel stop-gain variant (NM_000339.3:c.137del [p.His47fs]) and a missense variant (NM_000339.3:c.2927C > T [p.Ser976Phe]) in the SLC12A3 gene. This novel pathogenic variant was located at the intracellular N-terminus of the NCC. Based on these findings, the patient was diagnosed with Gitelman syndrome. The use of next-generation sequencing facilitated the exclusion of diseases with similar clinical symptoms.
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Affiliation(s)
- Kenichiro Iio
- Department of Nephrology, National Hospital Organization Osaka Minami Medical Center, 2-1 Kidohigashimachi, Kawachinagano, Osaka, 586-8521, Japan.
| | - Takayasu Mori
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8510, Japan
| | - Saki Bessho
- Department of Nephrology, National Hospital Organization Osaka Minami Medical Center, 2-1 Kidohigashimachi, Kawachinagano, Osaka, 586-8521, Japan
| | - Yosuke Imai
- Department of Nephrology, National Hospital Organization Osaka Minami Medical Center, 2-1 Kidohigashimachi, Kawachinagano, Osaka, 586-8521, Japan
| | - Masaki Hatanaka
- Department of Nephrology, National Hospital Organization Osaka Minami Medical Center, 2-1 Kidohigashimachi, Kawachinagano, Osaka, 586-8521, Japan
| | - Hiroki Omori
- Department of Nephrology, National Hospital Organization Osaka Minami Medical Center, 2-1 Kidohigashimachi, Kawachinagano, Osaka, 586-8521, Japan
| | - Haruhiko Kouhara
- Department of Endocrinology and Metabolism, Osaka Minami Medical Center, 2-1 Kidohigashimachi, Kawachinagano, Osaka, 586-8521, Japan
| | - Motoko Chiga
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8510, Japan
| | - Eisei Sohara
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8510, Japan
| | - Shinichi Uchida
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8510, Japan
| | - Jun-Ya Kaimori
- Department of Inter-Organ Communication Research in Kidney Disease, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, 565-0871, Japan
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21
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Bockenhauer D, Kleta R. Tubulopathy meets Sherlock Holmes: biochemical fingerprinting of disorders of altered kidney tubular salt handling. Pediatr Nephrol 2021; 36:2553-2561. [PMID: 34143300 PMCID: PMC8260524 DOI: 10.1007/s00467-021-05098-5] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 04/27/2021] [Indexed: 11/19/2022]
Abstract
Evolution moves in mysterious ways. Excretion of waste products by glomerular filtration made perfect sense when life evolved in the ocean. Yet, the associated loss of water and solutes became a problem when life moved onto land: a serious design change was needed and this occurred in the form of ever more powerful tubules that attached to the glomerulus. By reabsorbing typically more than 99% of the glomerular filtrate, the tubules not only minimise urinary losses, but, crucially, also maintain homeostasis: tubular reabsorption and secretion are adjusted so as to maintain an overall balance, in which urine volume and composition matches intake and environmental stressors. A whole orchestra of highly specialised tubular transport proteins is involved in this process and dysfunction of one or more of these results in the so-called kidney tubulopathies, characterised by specific patterns of clinical and biochemical abnormalities. In turn, recognition of these patterns helps establish a specific diagnosis and pinpoints the defective transport pathway. In this review, we will discuss these clinical and biochemical "fingerprints" of tubular disorders of salt-handling and how sodium handling affects volume homeostasis but also handling of other solutes.
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Affiliation(s)
- Detlef Bockenhauer
- Department of Renal Medicine, University College London, NW3 2PF, London, UK. .,Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK.
| | - Robert Kleta
- Department of Renal Medicine, University College London, NW3 2PF, London, UK.,Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
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22
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Schlingmann KP, Renigunta A, Hoorn EJ, Forst AL, Renigunta V, Atanasov V, Mahendran S, Barakat TS, Gillion V, Godefroid N, Brooks AS, Lugtenberg D, Lake J, Debaix H, Rudin C, Knebelmann B, Tellier S, Rousset-Rouvière C, Viering D, de Baaij JHF, Weber S, Palygin O, Staruschenko A, Kleta R, Houillier P, Bockenhauer D, Devuyst O, Vargas-Poussou R, Warth R, Zdebik AA, Konrad M. Defects in KCNJ16 Cause a Novel Tubulopathy with Hypokalemia, Salt Wasting, Disturbed Acid-Base Homeostasis, and Sensorineural Deafness. J Am Soc Nephrol 2021; 32:1498-1512. [PMID: 33811157 PMCID: PMC8259640 DOI: 10.1681/asn.2020111587] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 02/04/2021] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND The transepithelial transport of electrolytes, solutes, and water in the kidney is a well-orchestrated process involving numerous membrane transport systems. Basolateral potassium channels in tubular cells not only mediate potassium recycling for proper Na+,K+-ATPase function but are also involved in potassium and pH sensing. Genetic defects in KCNJ10 cause EAST/SeSAME syndrome, characterized by renal salt wasting with hypokalemic alkalosis associated with epilepsy, ataxia, and sensorineural deafness. METHODS A candidate gene approach and whole-exome sequencing determined the underlying genetic defect in eight patients with a novel disease phenotype comprising a hypokalemic tubulopathy with renal salt wasting, disturbed acid-base homeostasis, and sensorineural deafness. Electrophysiologic studies and surface expression experiments investigated the functional consequences of newly identified gene variants. RESULTS We identified mutations in the KCNJ16 gene encoding KCNJ16, which along with KCNJ15 and KCNJ10, constitutes the major basolateral potassium channel of the proximal and distal tubules, respectively. Coexpression of mutant KCNJ16 together with KCNJ15 or KCNJ10 in Xenopus oocytes significantly reduced currents. CONCLUSIONS Biallelic variants in KCNJ16 were identified in patients with a novel disease phenotype comprising a variable proximal and distal tubulopathy associated with deafness. Variants affect the function of heteromeric potassium channels, disturbing proximal tubular bicarbonate handling as well as distal tubular salt reabsorption.
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Affiliation(s)
- Karl P. Schlingmann
- Department of General Pediatrics, Pediatric Nephrology, University Children’s Hospital, Munster, Germany
| | - Aparna Renigunta
- Department of Pediatric Nephrology, Marburg Kidney Research Center, Philipps University, Marburg, Germany
| | - Ewout J. Hoorn
- Division of Nephrology and Transplantation, Department of Internal Medicine, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Anna-Lena Forst
- Department of Physiology, Medical Cell Biology, University of Regensburg, Regensburg, Germany
| | - Vijay Renigunta
- Department of Neurophysiology, Institute of Physiology and Pathophysiology, Philipps University, Marburg, Germany
| | - Velko Atanasov
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | - Sinthura Mahendran
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | | | - Valentine Gillion
- Division of Nephrology, Saint-Luc Academic Hospital, Université Catholique Louvain, Brussels, Belgium
| | - Nathalie Godefroid
- Division of Pediatric Nephrology, Saint-Luc Academic Hospital, Université Catholique Louvain, Brussels, Belgium
| | - Alice S. Brooks
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Dorien Lugtenberg
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jennifer Lake
- Department of Physiology, Mechanism of Inherited Kidney Disorders, University of Zurich, Zurich, Switzerland
| | - Huguette Debaix
- Department of Physiology, Mechanism of Inherited Kidney Disorders, University of Zurich, Zurich, Switzerland
| | - Christoph Rudin
- Department of Pediatric Nephrology, University Children’s Hospital, Basel, Switzerland
| | - Bertrand Knebelmann
- Department of Nephrology-Transplantation, Assistance Publique Hôpitaux de Paris, Hôpital Necker, Paris, France,Reference Center for Hereditary Kidney and Childhood Diseases (MAladies Renales Hereditaires de l'Enfant et de l'Adulte), Paris, France
| | - Stephanie Tellier
- Department of Pediatric Nephrology, and Rheumatology, French Reference Center of Rare Renal Diseases (SORARE), CHU Toulouse, Toulouse, France,Division of Rheumatology, Department of Pediatrics, Centre Hospitalier Universitaire de Toulouse, Toulouse, France
| | - Caroline Rousset-Rouvière
- Department of Multidisciplinary Pediatrics, Pediatric Nephrology Unit, La Timone, University Hospital of Marseille, Marseille, France
| | - Daan Viering
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jeroen H. F. de Baaij
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Stefanie Weber
- Department of Pediatric Nephrology, Marburg Kidney Research Center, Philipps University, Marburg, Germany
| | - Oleg Palygin
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Alexander Staruschenko
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin,Clement J. Zablocki Veterans Affairs Medical Center, Milwaukee, Wisconsin
| | - Robert Kleta
- Department of Renal Medicine, University College London, London, United Kingdom,Department of Paediatric Nephrology, Great Ormond Street Hospital for Children National Health Service Foundation Trust, London, United Kingdom
| | - Pascal Houillier
- Reference Center for Hereditary Kidney and Childhood Diseases (MAladies Renales Hereditaires de l'Enfant et de l'Adulte), Paris, France,Department of Physiology, Assistance Publique Hôpitaux de Paris, Hôpital Européen Georges-Pompidou, Paris, France,Department of Renal Physiology, Centre de Recherche des Cordeliers, Institut National de la Santé et de la Recherche Médicale, Sorbonne Université, Université de Paris, Centre National de la Recherche Scientifique, Paris, France
| | - Detlef Bockenhauer
- Department of Renal Medicine, University College London, London, United Kingdom,Department of Paediatric Nephrology, Great Ormond Street Hospital for Children National Health Service Foundation Trust, London, United Kingdom
| | - Olivier Devuyst
- Division of Nephrology, Saint-Luc Academic Hospital, Université Catholique Louvain, Brussels, Belgium,Department of Physiology, Mechanism of Inherited Kidney Disorders, University of Zurich, Zurich, Switzerland
| | - Rosa Vargas-Poussou
- Reference Center for Hereditary Kidney and Childhood Diseases (MAladies Renales Hereditaires de l'Enfant et de l'Adulte), Paris, France,Department of Renal Physiology, Centre de Recherche des Cordeliers, Institut National de la Santé et de la Recherche Médicale, Sorbonne Université, Université de Paris, Centre National de la Recherche Scientifique, Paris, France,Department of Genetics, Assistance Publique Hôpitaux de Paris, Hôpital Européen Georges-Pompidou, Paris, France
| | - Richard Warth
- Department of Physiology, Medical Cell Biology, University of Regensburg, Regensburg, Germany
| | - Anselm A. Zdebik
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom,Department of Renal Medicine, University College London, London, United Kingdom
| | - Martin Konrad
- Department of General Pediatrics, Pediatric Nephrology, University Children’s Hospital, Munster, Germany
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23
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Riaño Ondiviela A, Meseguer González D, Ruiz Arroyo JR. Malignant ventricular arrhythmias in a patient with Gitelman syndrome. Med Clin (Barc) 2021; 157:550. [PMID: 33743984 DOI: 10.1016/j.medcli.2020.12.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 12/01/2020] [Accepted: 12/03/2020] [Indexed: 11/16/2022]
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24
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Singhal A, Vishnu Tewari V. Case 1: A Preterm Neonate with Polyhydramnios, Polyuria, and Hearing Loss. Neoreviews 2021; 22:e189-e193. [PMID: 33649091 DOI: 10.1542/neo.22-3-e189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- Amit Singhal
- Department of Pediatrics, Army Hospital (Referral and Research), New Delhi, India
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25
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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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26
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Franken GAC, Adella A, Bindels RJM, Baaij JHF. Mechanisms coupling sodium and magnesium reabsorption in the distal convoluted tubule of the kidney. Acta Physiol (Oxf) 2021; 231:e13528. [PMID: 32603001 PMCID: PMC7816272 DOI: 10.1111/apha.13528] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 05/29/2020] [Accepted: 06/22/2020] [Indexed: 02/06/2023]
Abstract
Hypomagnesaemia is a common feature of renal Na+ wasting disorders such as Gitelman and EAST/SeSAME syndrome. These genetic defects specifically affect Na+ reabsorption in the distal convoluted tubule, where Mg2+ reabsorption is tightly regulated. Apical uptake via TRPM6 Mg2+ channels and basolateral Mg2+ extrusion via a putative Na+ -Mg2+ exchanger determines Mg2+ reabsorption in the distal convoluted tubule. However, the mechanisms that explain the high incidence of hypomagnesaemia in patients with Na+ wasting disorders of the distal convoluted tubule are largely unknown. In this review, we describe three potential mechanisms by which Mg2+ reabsorption in the distal convoluted tubule is linked to Na+ reabsorption. First, decreased activity of the thiazide-sensitive Na+ /Cl- cotransporter (NCC) results in shortening of the segment, reducing the Mg2+ reabsorption capacity. Second, the activity of TRPM6 and NCC are determined by common regulatory pathways. Secondary effects of NCC dysregulation such as hormonal imbalance, therefore, might disturb TRPM6 expression. Third, the basolateral membrane potential, maintained by the K+ permeability and Na+ -K+ -ATPase activity, provides the driving force for Na+ and Mg2+ extrusion. Depolarisation of the basolateral membrane potential in Na+ wasting disorders of the distal convoluted tubule may therefore lead to reduced activity of the putative Na+ -Mg2+ exchanger SLC41A1. Elucidating the interconnections between Mg2+ and Na+ transport in the distal convoluted tubule is hampered by the currently available models. Our analysis indicates that the coupling of Na+ and Mg2+ reabsorption may be multifactorial and that advanced experimental models are required to study the molecular mechanisms.
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Affiliation(s)
- Gijs A. C. Franken
- Department of Physiology Radboud Institute for Molecular Life SciencesRadboud University Medical Center Nijmegen the Netherlands
| | - Anastasia Adella
- Department of Physiology Radboud Institute for Molecular Life SciencesRadboud University Medical Center Nijmegen the Netherlands
| | - René J. M. Bindels
- Department of Physiology Radboud Institute for Molecular Life SciencesRadboud University Medical Center Nijmegen the Netherlands
| | - Jeroen H. F. Baaij
- Department of Physiology Radboud Institute for Molecular Life SciencesRadboud University Medical Center Nijmegen the Netherlands
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27
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Ortiz A. Ckj consolidation among Q1 Urology and Nephrology journals. Clin Kidney J 2020; 13:723-727. [PMID: 33123351 PMCID: PMC7577766 DOI: 10.1093/ckj/sfaa197] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 09/02/2020] [Indexed: 12/21/2022] Open
Abstract
The Clinical Kidney Journal (ckj) impact factor from Clarivate’s Web of Science for 2019 was 3.388. This consolidates ckj among journals in the top 25% (first quartile, Q1) in the Urology and Nephrology field according to the journal impact factor. The manuscripts contributing the most to the impact factor focused on chronic kidney disease (CKD) epidemiology and evaluation, CKD complications and their management, cost-efficiency of renal replacement therapy, pathogenesis of CKD, familial kidney disease and the environment–genetics interface, onconephrology, technology, SGLT2 inhibitors and outcome prediction. We provide here an overview of the hottest and most impactful topics for 2017–19.
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Affiliation(s)
- Alberto Ortiz
- IIS-Fundación Jiménez Diaz, Department of Medicine, School of Medicine, Universidad Autónoma de Madrid, Madrid, Spain.,Red de Investigación Renal (REDINREN), Instituto Carlos III-FEDER, Madrid, Spain
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28
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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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29
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Elfert KA, Geller DS, Nelson-Williams C, Lifton RP, Al-Malki H, Nauman A. Late-Onset Bartter Syndrome Type II Due to a Homozygous Mutation in KCNJ1 Gene: A Case Report and Literature Review. AMERICAN JOURNAL OF CASE REPORTS 2020; 21:e924527. [PMID: 32997650 PMCID: PMC7534490 DOI: 10.12659/ajcr.924527] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
BACKGROUND Bartter syndrome is a rare genetic disease characterized by hypokalemia, metabolic alkalosis, and hyperreninemic hyperaldosteronism. Five different subtypes have been described based on the genetic defect identified. Bartter syndrome type II is caused by homozygous or compound heterozygous loss-of-function mutations in the KCNJ1 gene encoding ROMK. This subtype is typically described as a severe antenatal form of the disease, often presenting with polyhydramnios before childbirth. CASE REPORT Here, we describe the case of a 26-year-old man who presented with generalized body weakness and hypokalemia and was ultimately diagnosed with Bartter syndrome type II based on his clinical features coupled with the identification of a homozygous missense mutation in KCNJ1. CONCLUSIONS To the best of our knowledge, this is the fifth case of late-onset Bartter syndrome type II. Interestingly, the mutation identified in our patient has been previously described in patients with antenatal Bartter's Syndrome. The late presentation in our patient suggests a surprising degree of phenotypic variability, even in patients carrying the identical disease-causing mutation.
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Affiliation(s)
- Khaled A Elfert
- Department of Internal Medicine, Hamad Medical Corporation, Doha, Qatar
| | - David S Geller
- Department of Nephrology, Yale University School of Medicine, New Haven, CT, USA.,Department of Nephrology, West Haven VA Hospital, West Haven, CT, USA
| | | | - Richard P Lifton
- Department of Genetics, Yale University School of Medicine, New Haven, CT, USA
| | - Hassan Al-Malki
- Department of Nephrology, Hamad Medical Corporation, Doha, Qatar
| | - Awais Nauman
- Department of Nephrology, Hamad Medical Corporation, Doha, Qatar
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He G, Gang X, Sun Z, Wang P, Wang G, Guo W. Type 2 diabetes mellitus caused by Gitelman syndrome-related hypokalemia: A case report. Medicine (Baltimore) 2020; 99:e21123. [PMID: 32702863 PMCID: PMC7373581 DOI: 10.1097/md.0000000000021123] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [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
INTRODUCTION Gitelman syndrome (GS) is an autosomal-recessive disease caused by SLC12A3 gene mutations. It is characterized by hypokalemic metabolic alkalosis in combination with hypomagnesemia and hypocalciuria. Recently, patients with GS are found at an increased risk for developing type 2 diabetes mellitus (T2DM). However, diagnosis of hyperglycemia in GS patients has not been thoroughly investigated, and family studies on SLC12A3 mutations and glucose metabolism are rare. Whether treatment including potassium and magnesium supplements, and spironolactone can ameliorate impaired glucose tolerance in GS patients, also needs to be investigated. PATIENT CONCERNS We examined a 55-year-old Chinese male with intermittent fatigue and persistent hypokalemia for 17 years. DIAGNOSES Based on the results of the clinical data, including electrolytes, oral glucose tolerance test (OGTT), and genetic analysis of the SLC12A3 gene, GS and T2DM were newly diagnosed in the patient. Two mutations of the SLC12A3 gene were found in the patient, one was a missense mutation p.N359K in exon 8, and the other was a novel insert mutation p.I262delinsIIGVVSV in exon 6. SLC12A3 genetic analysis and OGTT of 9 other family members within 3 generations were also performed. Older brother, youngest sister, and son of the patient carried the p.N359K mutation in exon 8. The older brother and the youngest sister were diagnosed with T2DM and impaired glucose tolerance by OGTT, respectively. INTERVENTIONS The patient was prescribed potassium and magnesium (potassium magnesium aspartate, potassium chloride) oral supplements and spironolactone. The patient was also suggested to maintain a high potassium diet. Acarbose was used to maintain the blood glucose levels. OUTCOMES The electrolyte imbalance including hypokalemia and hypomagnesemia, and hyperglycemia were improved with a remission of the clinical manifestations. CONCLUSION GS is one of the causes for manifestation of hypokalemia. SLC12A3 genetic analysis plays an important role in diagnosis of GS. Chinese male GS patients characterized with heterozygous SLC12A3 mutation should be careful toward occurrence of T2DM. Moreover, the patients with only 1 SLC12A3 mutant allele should pay regular attention to blood potassium and glucose levels. GS treatment with potassium and magnesium supplements, and spironolactone can improve impaired glucose metabolism.
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Affiliation(s)
- Guangyu He
- Department of Endocrinology and Metabolism
| | | | | | - Ping Wang
- Department of Otolaryngology-Head and Neck Surgery, The First Hospital of Jilin University, Changchun, Jilin, P.R. China
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Giri D, Bockenhauer D, Deshpande C, Achermann JC, Taylor NF, Rumsby G, Morgan H, Senniappan S, Ajzensztejn M. Co-Existence of Congenital Adrenal Hyperplasia and Bartter Syndrome due to Maternal Uniparental Isodisomy of HSD3B2 and CLCNKB Mutations. Horm Res Paediatr 2020; 93:137-142. [PMID: 32506065 DOI: 10.1159/000507577] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Accepted: 03/25/2020] [Indexed: 01/02/2023] Open
Abstract
INTRODUCTION We present a patient with co-existence of 3β-hydroxysteroid dehydrogenase type 2 (HSD3B2) deficiency and Bartter syndrome, a unique dual combination of opposing pathologies that has not been reported previously in the literature. CASE A female infant (46,XX) born at 34/40 weeks' gestation, weighing 2.67 kg (-1.54 standard deviation score) to non-consanguineous parents presented on day 4 of life with significant weight loss. Subsequent investigations revealed hyponatraemia, hypochloraemia, metabolic alkalosis, elevated 17-hydroxyprogesterone, ACTH, and renin. Urine steroid profile suggested HSD3B2 deficiency, which was confirmed by the identification of a homozygous HSD3B2 mutation. Due to the persistence of the hypochlo-raemic and hypokalemic alkalosis, an underlying renal tubulopathy was suspected. Sequence analysis of a targeted tubulopathy gene panel revealed a homozygous deletion in CLCNKB, consistent with Bartter syndrome type 3. The mother was found to be heterozygous for both mutations in -HSD3B2 and CLCNKB, and the father was negative for both. Single-nucleotide polymorphism microarray analysis confirmed 2 segments of homozygosity on chromosome 1 of maternal ancestry, encompassing both HSD3B2 and CLCKNB. DISCUSSION Identification of a homozygous rare mutation in an offspring of non-consanguineous parents should raise suspicion of uniparental disomy, especially if the phenotype is unusual, potentially encompassing more than one disorder. The persistence of hypokalemic alkalosis, the biochemical fingerprint of hyperaldosteronism in a child with a form of CAH in which aldosterone production is severely impaired, challenges our current understanding of mineralocorticoid-mediated effects in the collecting duct.
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Affiliation(s)
- Dinesh Giri
- Bristol Royal Hospital for Children, University Hospitals Bristol NHS Foundation Trust, Bristol, United Kingdom,
- Department of Translational Health Sciences, University of Bristol, Bristol, United Kingdom,
| | - Detlef Bockenhauer
- Great Ormond Street Hospital for Children NHS Foundation Trust, London, United Kingdom
| | - Charu Deshpande
- Guy's and St Thomas' Hospital NHS Foundation Trust, London, United Kingdom
| | - John C Achermann
- UCL GOS Institute of Child Health, University College of London, London, United Kingdom
| | - Norman F Taylor
- King's College Hospital NHS Foundation Trust, London, United Kingdom
| | - Gill Rumsby
- University College of London Hospital NHS Foundation Trust, London, United Kingdom
| | - Henry Morgan
- Alder Hey Children's Hospital NHS Foundation Trust, Liverpool, United Kingdom
| | - Senthil Senniappan
- Alder Hey Children's Hospital NHS Foundation Trust, Liverpool, United Kingdom
| | - Michal Ajzensztejn
- Guy's and St Thomas' Hospital NHS Foundation Trust, London, United Kingdom
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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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Khandelwal P, Sabanadesan J, Sinha A, Hari P, Bagga A. Isolated nephrocalcinosis due to compound heterozygous mutations in renal outer medullary potassium channel. CEN Case Rep 2020; 9:232-236. [PMID: 32185747 DOI: 10.1007/s13730-020-00464-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 03/03/2020] [Indexed: 02/06/2023] Open
Abstract
Identification of a monogenic etiology is possible in a proportion of patients with childhood-onset nephrolithiasis or nephrocalcinosis. Bartter syndrome (BS), a hereditary tubulopathy characterized by polyuria, hypokalemic alkalosis and growth retardation that rarely presents with isolated nephrocalcinosis. Patients with defect in renal outer medullary potassium channel, encoded by the KCNJ1 gene causing BS type 2, typically present during the neonatal period. We describe a 14-year-old girl with mild late-onset BS type 2 with reported pathogenic compound heterozygous variations in exon 2 of KCNJ1 (c.146G > A and c.657C > G). This patient presented with isolated medullary nephrocalcinosis due to hypercalciuria; absence of hypokalemia and metabolic alkalosis was unique. This case highlights the importance of screening the KCNJ1 gene in patients with hypercalciuria and nephrocalcinosis, even in older children.
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Affiliation(s)
- Priyanka Khandelwal
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029, India
| | - Jasintha Sabanadesan
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029, India
| | - Aditi Sinha
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029, India
| | - Pankaj Hari
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029, India
| | - Arvind Bagga
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029, India.
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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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35
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Wang X, Ding Y, Liu Q, Yang G. A novel compound heterozygous mutation of SLC12A3 gene in a Chinese pedigree with Gitelman syndrome. Endocrine 2020; 67:673-677. [PMID: 31808035 DOI: 10.1007/s12020-019-02152-z] [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: 11/08/2019] [Accepted: 11/26/2019] [Indexed: 11/28/2022]
Abstract
PURPOSE Gitelman syndrome (GS) is an autosomal recessive renal tubular disorder characterized by salt wasting and hypokalemia resulting from loss-of-function mutations in the solute carrier family 12A3 (SLC12A3) gene encoding the thiazide-sensitive NaCl cotransporter (NCC). Here, we investigated the clinical manifestations and genetic features of a Chinese pedigree with GS. METHODS Next-generation sequencing and Sanger sequencing analysis were performed to define and confirm the SLC12A3 gene mutations of the patient (proband II:1) and this pedigree. Clinical manifestations and biochemical parameters were collected and analyzed. RESULTS Genetic analysis of the SLC12A3 gene identified two novel mutations in the proband, heterozygous (c.2842delT) and heterozygous (c.1569_1586del) mutation, respectively. Additionally, heterozygous (c.2842delT) mutation in SLC12A3 gene was found in his father and younger brother. The other heterozygous (c.1569_1586del) mutation in SLC12A3 gene was carried by his mother. CONCLUSIONS Two novel mutations may be related to the occurrence of the GS in the pedigree. However, additional studies are particularly required to explore the underlying molecular mechanisms.
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Affiliation(s)
- Xin Wang
- Department of Rheumatology, Shaoxing People's Hospital (Shaoxing Hospital, Zhejiang University School of Medicine), 312000, Shaoxing, People's Republic of China
| | - Yu Ding
- Central Laboratory, Hangzhou First People's Hospital, Zhejiang University School of Medicine, 310006, Hangzhou, People's Republic of China
| | - Qi Liu
- Department of Transfusion, Shaoxing People's Hospital (Shaoxing Hospital, Zhejiang University School of Medicine), 312000, Shaoxing, People's Republic of China.
| | - Guocan Yang
- Department of Transfusion, Shaoxing People's Hospital (Shaoxing Hospital, Zhejiang University School of Medicine), 312000, Shaoxing, People's Republic of China.
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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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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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Hsiao PJ, Liao CY, Kao YH, Chan JS, Lin YF, Chuu CP, Chen JS. Comparison of fractional excretion of electrolytes in patients at different stages of chronic kidney disease: A cross-sectional study. Medicine (Baltimore) 2020; 99:e18709. [PMID: 31914079 PMCID: PMC6959939 DOI: 10.1097/md.0000000000018709] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Kidney handling of electrolytes varies in different stages of chronic kidney disease (CKD). Diabetes mellitus (DM) plays an important role in CKD. Fractional excretion (FE) is an important means in clinical practice. The relationship between FE of electrolytes in patients at different stages of CKD is worth further investigating.We designed a cross-sectional study in 1 teaching hospital, consecutive CKD patients were enrolled between February 2016 and January 2017. Including clinical demographic features, laboratory examination including spot urine electrolytes, blood biochemistries, and relevant medications were determined.A total of 762 CKD patients completed the study. Of these, 218 (28.6%) had DM. Participants were grouped according to estimated glomerular filtration rate into 7 categories: hyperfiltration (HF), CKD1, CKD2, CKD3a, CKD3b, CKD4, and CKD5. Groups HF, CKD1, 2, 3a, 3b, 4 and 5 contained 83, 143, 192, 94, 82, 82, and 86 patients, respectively. FE of electrolytes tended to increase along with the decline of renal function (CKD1-CKD5) (P < .001). The relationship was similar between the DM and non-DM groups. Diabetic patients demonstrated higher FE of magnesium compared with non-DM subjects at CKD2 and CKD5 (P < .05).CKD patients showed a progressive increase in the FE of electrolytes; FE of magnesium seemed to increase more among diabetic patients with CKD, and could be a potential predictor of CKD progression.
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Affiliation(s)
- Po-Jen Hsiao
- Division of Nephrology, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei
- Division of Nephrology, Department of Internal Medicine, Taoyuan Armed Forces General Hospital, Taiwan
- Division of Nephrology, Department of Medicine, Fu Jen Catholic University Hospital, School of Medicine, Fu Jen Catholic University
- Department of Life Sciences, National Central University, Taoyuan City
| | - Chen-Yi Liao
- Division of Nephrology, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei
- Division of Nephrology, Department of Medicine, Kaohsiung Armed Forces General Hospital
| | - Yung-Hsi Kao
- Department of Life Sciences, National Central University, Taoyuan City
| | - Jenq-Shyong Chan
- Division of Nephrology, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei
- Division of Nephrology, Department of Internal Medicine, Taoyuan Armed Forces General Hospital, Taiwan
| | - Yuh-Feng Lin
- Division of Nephrology, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei
- Division of Nephrology, Department of Internal Medicine, Shuang Ho Hospital
- Graduate Institute of Clinical Medicine, Taipei Medical University, Taipei
| | - Chih-Pin Chuu
- Institute of Cellular and System Medicine, National Health Research Institutes
- Graduate Program for Aging, China Medical University, Taichung City
| | - Jin-Shuen Chen
- Division of Nephrology, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei
- Department of Medical Education and Research
- Division of Nephrology, Department of Medicine, Kaohsiung Veterans General Hospital, Kaohsiung City, Taiwan, Republic of China
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Chinen T, Saeki E, Mori T, Sohara E, Uchida S, Akimoto T. A case of Gitelman syndrome: our experience with a patient treated in clinical practice on a local island. J Rural Med 2019; 14:258-262. [PMID: 31788154 PMCID: PMC6877917 DOI: 10.2185/jrm.3014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 05/31/2019] [Indexed: 12/28/2022] Open
Abstract
Background: Gitelman syndrome (GS) is an autosomal recessive salt-losing
renal tubulopathy resulting from mutations in the thiazide-sensitive Na-Cl cotransporter
(NCC) gene. Notably, lack of awareness regarding GS and difficulty with
prompt diagnosis are observed in clinical practice, particularly in rural settings. Case presentation: We report a case of a 48-year-old man with GS who
presented to a local clinic on a remote island. Occasional laboratory investigations
incidentally revealed a reduced serum potassium level of 2.6 mmol/L. A careful medical
interview revealed episodes of intermittent paralysis of the lower extremities and
muscular weakness for >30 years. Subsequent laboratory investigations revealed
hypomagnesemia, hypocalciuria, and hypokalemic metabolic alkalosis. Based on the patient’s
history, clinical presentation, and laboratory investigations, we suspected GS. Genetic
testing revealed a rare homozygous in-frame 18 base insertion in the NCC
gene that might have resulted from the founder effect, consequent to his topographically
isolated circumstances. Conclusion: More case studies similar to our study need to be added to the
literature to gain a deeper understanding of the functional consequences of this mutation
and to establish optimal management strategies for this condition, particularly in rural
clinical settings.
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Affiliation(s)
- Takashi Chinen
- Department of Clinical Oncology, Jichi Medical University, Japan.,Setouchi-Cho Hekichi Clinic, Japan
| | - Eiji Saeki
- Division of Nephrology, Department of Internal Medicine, Amami Central Hospital, Japan
| | - Takayasu Mori
- Department of Nephrology, Tokyo Medical and Dental University, Japan
| | - Eisei Sohara
- Department of Nephrology, Tokyo Medical and Dental University, Japan
| | - Shinichi Uchida
- Department of Nephrology, Tokyo Medical and Dental University, Japan
| | - Tetsu Akimoto
- Division of Nephrology, Department of Internal Medicine, Jichi Medical University, Japan
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Halperin D, Dolgin V, Geylis M, Drabkin M, Yogev Y, Wormser O, Schreiber R, Shalev H, Landau D, Birk OS. A novel SLC12A1 mutation in Bedouin kindred with antenatal Bartter syndrome type I. Ann Hum Genet 2019; 83:361-366. [PMID: 30977917 DOI: 10.1111/ahg.12317] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 02/18/2019] [Accepted: 03/26/2019] [Indexed: 12/01/2022]
Abstract
Four affected individuals of consanguineous kindred presented at infancy with an apparently autosomal recessive syndrome of polyuria and hypokalemic metabolic alkalosis, following maternal polyhydramnios and premature delivery, culminating in severe failure to thrive. Hypercalciuria, nephrocalcinosis, and hyperaldosteronism were further apparent as well as an unusual finding of intermittent hypernatremia. Additionally, all patients demonstrated variable micrognathia with upper respiratory airway abnormalities. As neither postnatal hyperkalemia nor permanent hearing deficits were shown, clinical assessment was consistent with antenatal Bartter syndrome (ABS) type I, which was never described before in the Israeli Bedouin population. Through genome-wide linkage analysis, we identified a single ∼3.3 Mbp disease-associated locus on chromosome 15q21.1, segregating within the pedigree. Whole-exome sequencing revealed a single novel homozygous missense mutation within this locus, in SLC12A1, encoding the Na-K-Cl cotransporter, NKCC2, in accordance with the clinical diagnosis. In this concise study, we report a novel missense mutation within the SLC12A1 gene, causing a severe form of ABS type I, the first to be described in Israeli Bedouins, with unusual clinical features of hypernatremia caused by nephrogenic diabetes insipidus and putatively related micrognathia with upper airway abnormalities .
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Affiliation(s)
- Daniel Halperin
- The Morris Kahn Laboratory of Human Genetics, National Institute for Biotechnology in the Negev and Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Vadim Dolgin
- The Morris Kahn Laboratory of Human Genetics, National Institute for Biotechnology in the Negev and Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Michael Geylis
- Pediatric Nephrology Clinic, Soroka University Medical Center and Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Max Drabkin
- The Morris Kahn Laboratory of Human Genetics, National Institute for Biotechnology in the Negev and Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Yuval Yogev
- The Morris Kahn Laboratory of Human Genetics, National Institute for Biotechnology in the Negev and Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Ohad Wormser
- The Morris Kahn Laboratory of Human Genetics, National Institute for Biotechnology in the Negev and Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Ruth Schreiber
- Pediatric Nephrology Clinic, Soroka University Medical Center and Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Hanna Shalev
- Pediatric Nephrology Clinic, Soroka University Medical Center and Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Daniel Landau
- Pediatrics Department A, Soroka University Medical Center and Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel.,Pediatrics Department B, Schneider Children's Medical Center, Petah Tikva, Israel
| | - Ohad S Birk
- The Morris Kahn Laboratory of Human Genetics, National Institute for Biotechnology in the Negev and Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel.,Genetics Institute, Soroka University Medical Center, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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Ortiz A, Vinck C. The new Clinical Kidney Journal, 4 years later. Clin Kidney J 2019; 12:1-5. [PMID: 30746126 PMCID: PMC6366135 DOI: 10.1093/ckj/sfy139] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Accepted: 12/31/2018] [Indexed: 12/13/2022] Open
Abstract
The February 2015 issue of ckj started a new era with renewed efforts to be useful to the training and practicing nephrologists and a new focus on Clinical and Translational Nephrology. Four years later, it has become a truly global journal with contributors and readers from all over the world. The increase in quality of the published material has resulted in a nearly exponential growth of citations. Since 2016, ckj is listed in the new Emerging Sources Citation Index (ESCI) database from Clarivate Analytics and from January 2019 it will be listed in the full Science Citation Index. ckj will therefore receive its first official impact factor based upon 2018 citation to 2016 and 2017 articles. While no official impact factor was awarded for 2017, the estimated impact factors calculated from data available in Clarivate's Web of Science database rose to 2.987 in 2017, which would correspond to an estimated journal impact factor percentile of 72.4% in the Urology and Nephrology field.
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Affiliation(s)
- Alberto Ortiz
- Editor-in-Chief, Clinical Kidney Journal, IIS-Fundacion Jimenez Diaz, School of Medicine, Universidad Autonoma de Madrid; Fundacion Renal Iñigo Alvarez de Toledo-IRSIN and REDINREN, Madrid, Spain
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Kleta R, Bockenhauer D. Salt-Losing Tubulopathies in Children: What's New, What's Controversial? J Am Soc Nephrol 2018; 29:727-739. [PMID: 29237739 PMCID: PMC5827598 DOI: 10.1681/asn.2017060600] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Renal tubulopathies provide insights into the inner workings of the kidney, yet also pose therapeutic challenges. Because of the central nature of sodium in tubular transport physiology, disorders of sodium handling may affect virtually all aspects of the homeostatic functions of the kidney. Yet, owing to the rarity of these disorders, little clinical evidence regarding treatment exists. Consequently, treatment can vary widely between individual physicians and centers and is based mainly on understanding of renal physiology, reported clinical observations, and individual experiences. Salt-losing tubulopathies can affect all tubular segments, from the proximal tubule to the collecting duct. But the more frequently observed disorders are Bartter and Gitelman syndrome, which affect salt transport in the thick ascending limb of Henle's loop and/or the distal convoluted tubule, and these disorders generate the greatest controversies regarding management. Here, we review clinical and molecular aspects of salt-losing tubulopathies and discuss novel insights provided mainly by genetic investigations and retrospective clinical reviews. Additionally, we discuss controversial topics in the management of these disorders to highlight areas of importance for future clinical trials. International collaboration will be required to perform clinical studies to inform the treatment of these rare disorders.
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Affiliation(s)
- Robert Kleta
- UCL Centre for Nephrology and Great Ormond Street Hospital NHS Foundation Trust, London, United Kingdom
| | - Detlef Bockenhauer
- UCL Centre for Nephrology and Great Ormond Street Hospital NHS Foundation Trust, London, United Kingdom
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