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Yin Y, Li L, Yu S, Xin Y, Zhu L, Hu X, Chen K, Gu W, Mu Y, Zang L, Lyu Z. The first compound heterozygous mutations in SLC12A3 and PDX1 genes: a unique presentation of Gitelman syndrome with distinct insulin resistance and familial diabetes insights. Front Endocrinol (Lausanne) 2024; 14:1327729. [PMID: 38333726 PMCID: PMC10850558 DOI: 10.3389/fendo.2023.1327729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 12/27/2023] [Indexed: 02/10/2024] Open
Abstract
Background Gitelman Syndrome (GS) patients frequently exhibit disrupted glucose metabolism, attributed to hypokalemia, hypomagnesemia and heightened aldosterone. This study delved into the genetic underpinnings linked to insulin resistance and diabetes in a GS patient, contextualized within his family history. Methods The hydrochlorothiazide and furosemide loading test were performed to ascertain the presence of GS. Oral glucose tolerance test (OGTT) evaluated glucose metabolism and insulin sensitivity. Whole-exome sequencing, validated by Sanger sequencing, was employed to confirm gene mutations, which were then tracked among the patient's relatives. Results Symptoms and laboratory examination confirmed the clinical diagnosis of GS. Comprehensive whole-exome sequencing, augmented by Sanger sequencing validation, revealed a compound heterozygous mutation within the SLC12A3 gene (c.1108G>C in exon 9, c.676G>A in exon 5 and c.2398G>A in exon 20) in the patient. The OGTT affirmed diabetes and heightened insulin resistance, distinct from previous patients with GS we evaluated. Further genetic analysis identified a missense heterozygous mutation (c.97C>G in exon 1) within the PDX1 gene, inherited from the patient's diabetic mother without GS. Furthermore, the patient's brother, with impaired glucose tolerance but regular potassium levels, also bore this mutation, hinting at additional impacts of the PDX1 gene mutation on glucose metabolism regulation beyond the known impacts of GS. Conclusion This study unveils unprecedented compound heterozygous mutations in the SLC12A3 and PDX1 genes in a GS patient. These findings illuminate the potential complex genetic factors influencing glucose metabolism disruptions in GS. Take-home message This research uncovers a novel combination of SLC12A3 and PDX1 gene mutations in a Gitelman Syndrome patient, revealing intricate genetic factors that potentially disrupt glucose metabolism and shedding light on familial diabetes links.
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Affiliation(s)
- Yaqi Yin
- Department of Endocrinology, The First Medical Center of Chinese People’s Liberation Army General Hospital, Beijing, China
| | - Liqin Li
- Department of Endocrinology, Baoding No. 1 Central Hospital, Baoding, China
| | - Songyan Yu
- Department of Endocrinology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Yu Xin
- School of Medicine, Nankai University, Tianjin, China
| | - Lili Zhu
- Department of Endocrinology and Cardiology, TaiYuan No.8 People Hospital, Taiyuan, China
| | - Xiao Hu
- Department of Internal Medicine, The 63790th Hospital of Chinese People’s Liberation Army, Xichang, China
| | - Kang Chen
- Department of Endocrinology, The First Medical Center of Chinese People’s Liberation Army General Hospital, Beijing, China
| | - Weijun Gu
- Department of Endocrinology, The First Medical Center of Chinese People’s Liberation Army General Hospital, Beijing, China
| | - Yiming Mu
- Department of Endocrinology, The First Medical Center of Chinese People’s Liberation Army General Hospital, Beijing, China
| | - Li Zang
- Department of Endocrinology, The First Medical Center of Chinese People’s Liberation Army General Hospital, Beijing, China
| | - Zhaohui Lyu
- Department of Endocrinology, The First Medical Center of Chinese People’s Liberation Army General Hospital, Beijing, China
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Ying Q, Ye Z, Zhang W, Pan Y, Dai L, Lin K, Feng X, Dong X, He F. Novel SLC12A3 gene mutations and clinical characteristics in two pedigrees with Gitelman syndrome. Clin Endocrinol (Oxf) 2023; 99:474-480. [PMID: 36562655 DOI: 10.1111/cen.14870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 12/20/2022] [Accepted: 12/22/2022] [Indexed: 12/24/2022]
Abstract
OBJECTIVE Gitelman syndrome (GS) is an autosomal recessive tubulopathy resulting from inactivating mutations in the SLC12A3 gene that encodes the thiazide-sensitive sodium-chloride cotransporter (NCC). To date, more than 500 mutations have been identified in the SLC12A3 gene. In this study, we identified two new mutations in the SLC12A3 gene in two Chinese GS pedigrees. DESIGN, PATIENTS AND MEASUREMENTS The clinical characteristics and laboratory examination of two suspected GS patients in our hospital were analyzed. In addition, two pedigrees including 11 members and 2 patients underwent SLC12A3 gene analysis. RESULTS Both patients were middle-aged women with characteristics of hypokalemic metabolic alkalosis, hypomagnesemia, low level of urinary calcium and the elevated levels of renin-angiotensin-aldosterone system. So, they were clinically diagnosed as GS. Patient 2 also had type 2 diabetes and Graves' disease. Both patients were found to carry two mutations of SLC12A3 gene by Sanger direct sequencing, which were all compound heterozygous mutations. We identified three mutations in these two Chinese GS pedigrees, one of which was c.179C>T (Thr60Met). The novel c.2159G>T (p. Gly720Val) and c.2675T>C (p. Leu892Pro) mutations were strongly predicted to be pathogenic using four network programs-Polyphen-2, SIFT, Mutation Taster and LRT. CONCLUSIONS We identified two novel SLC12A3 genetic variant [c.2159G>T (p.Gly720Val) and c.2675T>C (p.Leu892Pro)] in two Chinese GS pedigrees. The discovery of new mutations has enriched the spectrum of SLC12A3 genotypes.
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Affiliation(s)
- Qiao Ying
- Department of Endocrinology and Metabolism, Taizhou Municipal Hospital, Taizhou, Zhejiang, People's Republic of China
| | - Zhinan Ye
- Department of Neurology, Taizhou Municipal Hospital, Taizhou, Zhejiang, People's Republic of China
| | - Wei Zhang
- Department of Endocrinology and Metabolism, Taizhou Municipal Hospital, Taizhou, Zhejiang, People's Republic of China
| | - Yingying Pan
- Department of Endocrinology and Metabolism, Taizhou Municipal Hospital, Taizhou, Zhejiang, People's Republic of China
| | - Linxiong Dai
- Department of Endocrinology and Metabolism, Taizhou Municipal Hospital, Taizhou, Zhejiang, People's Republic of China
| | - Kaisang Lin
- Department of Endocrinology and Metabolism, Taizhou Municipal Hospital, Taizhou, Zhejiang, People's Republic of China
| | - Xiaocheng Feng
- Department of Endocrinology and Metabolism, School of Medicine, Zhejiang University Affiliated Sir Run Shaw Hospital, Hangzhou, Zhejiang, People's Republic of China
| | - Xuehong Dong
- Department of Endocrinology and Metabolism, School of Medicine, Zhejiang University Affiliated Sir Run Shaw Hospital, Hangzhou, Zhejiang, People's Republic of China
| | - Fei He
- Department of Endocrinology and Metabolism, Taizhou Municipal Hospital, Taizhou, Zhejiang, People's Republic of China
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Tophaceous gout in a young man with Gitelman syndrome: a case report with an overview. Clin Rheumatol 2023; 42:285-291. [PMID: 36166102 DOI: 10.1007/s10067-022-06361-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 08/18/2022] [Accepted: 08/26/2022] [Indexed: 01/11/2023]
Abstract
Gitelman syndrome represents the clinical manifestations of inactivation of the Slc12a3 genes encoding the thiazide-sensitive sodium chloride cotransporter and the Trpm6-Mg genes encoding the magnesium transporters in the distal convoluted tubule. In fact, the biochemical findings resemble those with thiazide diuretics such as hypokalemia, hypomagnesaemia, hypocalciuria, metabolic alkalosis, and low normal blood pressure. He is usually associated with calcium pyrophosphate deposition. Serum uricemia level is rarely affected in Gitelman syndrome. We aimed to report a rare association of chronic gout with Gitelman syndrome, hence the interest of our case. We describe a 29-year-old male patient with a history of Gitelman syndrome associated with articular gout including pelvic localization. We provided pictorial evidence of extensive and diffuse monosodium urate deposition in articular and periarticular structures to confirm the gout origin. A literature review illustrates 4 reported cases of Gitelman syndrome associated with gout. The gender distribution was equal with a mean age of 40 years.
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Rosenbaek LL, Petrillo F, van Bemmelen MX, Staub O, Murali SK, Fenton RA. The E3 ubiquitin-protein ligase Nedd4-2 regulates the sodium chloride cotransporter NCC but is not required for a potassium-induced reduction of NCC expression. Front Physiol 2022; 13:971251. [PMID: 36160843 PMCID: PMC9490057 DOI: 10.3389/fphys.2022.971251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Accepted: 08/18/2022] [Indexed: 11/21/2022] Open
Abstract
Na+ and K+ balance is influenced by the activity of the sodium chloride cotransporter NCC in the distal convoluted tubule. NCC activity and abundance are reduced by high extracellular K+. The E3 ubiquitin ligase neural precursor cell expressed developmentally downregulated 4–2 (Nedd4-2) has been proposed as a modulator of NCC abundance. Here, we examined the functional role of Nedd4-2 on NCC regulation and whether Nedd4-2 is important for the effects of high extracellular K+ on NCC. Total and plasma membrane levels of ubiquitylated NCC were lower in NCC-expressing MDCKI cells after Nedd4-2 deletion. NCC and phosphorylated NCC (pT58-NCC) levels were higher after Nedd4-2 deletion, and NCC levels on the plasma membrane were elevated. No significant changes were seen after Nedd4-2 knockdown in the levels of SPAK and phosphorylated SPAK (pS373-SPAK), the major NCC regulatory kinase. Nedd4-2 deficiency had no effect on the internalization rate of NCC from the plasma membrane, but NCC protein half-life was increased. In ex vivo experiments with kidney tubule suspensions from Nedd4-2 knockout (KO) mice, high K+ reduced total and pT58-NCC regardless of genotype. We conclude that Nedd4-2 is involved in ubiquitylation of NCC and modulating its plasma membrane levels and degradation. However, Nedd4-2 does not appear to be important for K+ induced reductions in NCC abundance.
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Affiliation(s)
- Lena L. Rosenbaek
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
- Leducq Foundation Potassium in Hypertension International Network, Massachusetts, United States
| | | | - Miguel X. van Bemmelen
- Leducq Foundation Potassium in Hypertension International Network, Massachusetts, United States
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland
| | - Olivier Staub
- Leducq Foundation Potassium in Hypertension International Network, Massachusetts, United States
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland
| | - Sathish K. Murali
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
- Leducq Foundation Potassium in Hypertension International Network, Massachusetts, United States
- Department of Biomedical Sciences, University of Veterinary Medicine, Vienna, Austria
| | - Robert A. Fenton
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
- Leducq Foundation Potassium in Hypertension International Network, Massachusetts, United States
- *Correspondence: Robert A. Fenton,
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Rossanti R, Horinouchi T, Sakakibara N, Yamamura T, Nagano C, Ishiko S, Aoto Y, Kondo A, Nagai S, Awano H, Nagase H, Matsuo M, Iijima K, Nozu K. Detecting pathogenic deep intronic variants in Gitelman syndrome. Am J Med Genet A 2022; 188:2576-2583. [PMID: 35785516 DOI: 10.1002/ajmg.a.62885] [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: 01/28/2022] [Revised: 05/17/2022] [Accepted: 05/30/2022] [Indexed: 01/24/2023]
Abstract
Gitelman syndrome (GS) is a rare, autosomal recessive, salt-losing tubulopathy caused by loss of function in the SLC12A3 gene (NM_000339.2), which encodes the natrium chloride cotransporter. The detection of homozygous or compound heterozygous SLC12A3 variants is expected in GS, but 18%-40% of patients with clinical GS carry only one mutant allele. Previous reports identified some pathogenic deep intronic variants in SLC12A3. Here, we report the screening of SLC12A3 deep intronic variants in 13 patients with suspected GS carrying one mutated SLC12A3 allele. Variant screening used the HaloPlex Target Enrichment System Kit capturing whole introns and the promotor region of SLC12A3, followed by SureCall variant analysis. Rare intronic variants (<1% frequency) were identified, and pathogenicity evaluated by the minigene system. Deep intronic variant screening detected seven rare SLC12A3 variants from six patients. Only one variant showed pathogenicity in the minigene system (c.602-16G>A, intron 4) through activation of a cryptic acceptor site. No variants were detected in the promotor region. Deep intronic screening identified only one pathogenic variant in patients with suspected GS carrying monoallelic SLC12A3 variants. Our results suggest that deep intronic variants partially explain the cause of monoallelic variants in patients with GS.
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Affiliation(s)
- Rini Rossanti
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan.,Department of Child Health, Nephrology Division, Dr. Hasan Sadikin General Hospital/Faculty of Medicine, Universitas Padjadjaran, Bandung, Indonesia
| | - Tomoko Horinouchi
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Nana Sakakibara
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Tomohiko Yamamura
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - China Nagano
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Shinya Ishiko
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Yuya Aoto
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Atsushi Kondo
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Sadayuki Nagai
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Hiroyuki Awano
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Hiroaki Nagase
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Masafumi Matsuo
- Research Center for Locomotion Biology, Kobe Gakuin University, Kobe, Hyogo, Japan
| | - Kazumoto Iijima
- Hyogo Prefectural Kobe Children's Hospital, Kobe, Hyogo, Japan.,Department of Advanced Pediatric Medicine, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Kandai Nozu
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
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Huang CC, Chung CM, Yang CY, Leu HB, Huang PH, Lin LY, Wu TC, Lin SJ, Pan WH, Chen JW. SLC12A3 Variation and Renal Function in Chinese Patients With Hypertension. Front Med (Lausanne) 2022; 9:863275. [PMID: 35801212 PMCID: PMC9253539 DOI: 10.3389/fmed.2022.863275] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 04/19/2022] [Indexed: 11/29/2022] Open
Abstract
Objective SLC12A3 (solute carrier family 12 member 3) gene variants are associated with diabetic nephropathy; however, their association with hypertensive nephropathy remains unknown. We aimed to investigate the association between SLC12A3 gene polymorphisms and renal function in patients with hypertension. Methods Participants from three non-diabetic hypertensive cohorts, including young-onset hypertension (cohort 1, n = 882), treatment-naïve hypertension (cohort 2, n = 90), and follow-up cohort (cohort 3, n = 166), underwent genotyping for single nucleotide polymorphisms in SLC12A3. Renal events were defined as a >25 and >50% decline in estimated glomerular filtration rate (eGFR). Results In cohort 1, SLC12A3 rs16963397 C/C or C/G (P = 0.005), rs13334864 C/C or C/T (P = 0.020), and rs7187932 A/A or A/G polymorphisms (P = 0.014) had higher eGFRs compared to their counterparts, with similar findings observed in cohort 2. In cohort 3, over a mean follow-up of 5.8 ± 1.7 years, participants with either SLC12A3 rs16963397 C/C or rs13334864 C/C polymorphisms had more >25 and >50% eGFR decline than their counterparts (log-rank test, P = 0.058 and P = 0.038, respectively). Cox regression analysis revealed that SLC12A3 rs16963397 C/C and rs13334864 C/C polymorphisms were significantly associated with an increased risk of >25% [hazard ratio (HR), 3.294; 95% confidence interval (CI), 1.158–9.368; P = 0.025] and >50% decline in eGFR (HR, 18.630; 95% CI, 1.529–227.005, P = 0.022) than their counterparts. Conclusion SLC12A3 polymorphisms are associated with renal function in Chinese patients with hypertension.
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Affiliation(s)
- Chin-Chou Huang
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
- School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Institute of Pharmacology, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Cardiovascular Research Center, National Yang Ming Chiao Tung University, Taipei, Taiwan
- *Correspondence: Chin-Chou Huang ;
| | - Chia-Min Chung
- Center for Drug Abuse and Addiction, China Medical University Hospital, Taichung, Taiwan
- Graduate Institute of Biomedical Sciences, China Medical University, Taichung, Taiwan
| | - Chih-Yu Yang
- School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Institute of Clinical Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Division of Nephrology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Hsin-Bang Leu
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
- School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Cardiovascular Research Center, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Healthcare and Services Center, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Po-Hsun Huang
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
- Cardiovascular Research Center, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Institute of Clinical Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Department of Critical Care Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Liang-Yu Lin
- School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Cardiovascular Research Center, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Division of Endocrinology and Metabolism, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Tao-Cheng Wu
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
- School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Cardiovascular Research Center, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Shing-Jong Lin
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
- Cardiovascular Research Center, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Institute of Clinical Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Taipei Heart Institute, Taipei Medical University, Taipei, Taiwan
| | - Wen-Harn Pan
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
- Institute of Epidemiology, School of Public Health, National Taiwan University, Taipei, Taiwan
| | - Jaw-Wen Chen
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
- Institute of Pharmacology, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Cardiovascular Research Center, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Healthcare and Services Center, Taipei Veterans General Hospital, Taipei, Taiwan
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Li N, Gu HF. Genetic and Biological Effects of SLC12A3, a Sodium-Chloride Cotransporter, in Gitelman Syndrome and Diabetic Kidney Disease. Front Genet 2022; 13:799224. [PMID: 35591852 PMCID: PMC9111839 DOI: 10.3389/fgene.2022.799224] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 01/12/2022] [Indexed: 11/13/2022] Open
Abstract
The SLC12A3 (Solute carrier family 12 member 3) gene encodes a sodium-chloride cotransporter and mediates Na+ and Cl− reabsorption in the distal convoluted tubule of kidneys. An experimental study has previously showed that with knockdown of zebrafish ortholog, slc12a3 led to structural abnormality of kidney pronephric distal duct at 1-cell stage, suggesting that SLC12A3 may have genetic effects in renal disorders. Many clinical reports have demonstrated that the function-loss mutations in the SLC12A3 gene, mainly including Thr60Met, Asp486Asn, Gly741Arg, Leu859Pro, Arg861Cys, Arg913Gln, Arg928Cys and Cys994Tyr, play the pathogenic effects in Gitelman syndrome. This kidney disease is inherited as an autosomal recessive trait. In addition, several population genetic association studies have indicated that the single nucleotide variant Arg913Gln in the SLC12A3 gene is associated with diabetic kidney disease in type 2 diabetes subjects. In this review, we first summarized bioinformatics of the SLC12A3 gene and its genetic variation. We then described the different genetic and biological effects of SLC12A3 in Gitelman syndrome and diabetic kidney disease. We also discussed about further genetic and biological analyses of SLC12A3 as pharmacokinetic targets of diuretics.
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Affiliation(s)
- Nan Li
- Department of Endocrinology, Jiangsu Province Hospital of Traditional Chinese Medicine, The Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing, China
| | - Harvest F. Gu
- Laboratory of Molecular Medicine, School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing, China
- *Correspondence: Harvest F. Gu,
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KARAAHMETOĞLU S, COŞKUN MV. A Case of Gitelman Syndrome; Incidentally Diagnosed in Elderly. BEZMIALEM SCIENCE 2022. [DOI: 10.14235/bas.galenos.2020.4465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Zhang L, Huang K, Wang S, Fu H, Wang J, Shen H, Lu Z, Chen J, Bao Y, Feng C, Dong G, Mao J. Clinical and Genetic Features in 31 Serial Chinese Children With Gitelman Syndrome. Front Pediatr 2021; 9:544925. [PMID: 33996672 PMCID: PMC8116576 DOI: 10.3389/fped.2021.544925] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Accepted: 03/19/2021] [Indexed: 11/13/2022] Open
Abstract
Gitelman syndrome (GS, OMIM 263800) is a genetic congenital tubulopathy associated with salt loss, which is characterized by hypokalemic metabolic toxicity, hypocalciuria, and hypomagnesemia. GS, which is typically detected in adolescence or adulthood, has long been considered a benign tubular lesion; however, the disease is associated with a significant decrease in the quality of life. In this study, we assessed the genotype-phenotype correlations based on the medical histories, clinical symptoms, laboratory test results, and whole-exome sequencing profiles from pediatric patients with GS. Between January 2014 and December 2020, all 31 consecutively enrolled patients complained of fatigue, salt craving, and muscle weakness. Sixteen patients demonstrated growth retardation, and five patients presented with nocturia and constipation. All patients presented with hypokalemic metabolic alkalosis, normal blood pressure, hyperaldosteronism, and a preserved glomerular filtration rate, and 24 of the 31 (77.4%) patients had hypomagnesemia. Homozygous, compound heterozygous, and heterozygous mutations in SLC12A3 were detected in 4, 24, and 3 patients, respectively. GS patients often present with muscle weakness and fatigue caused by hypokalemia and hypomagnesemia. Therefore, early diagnosis of GS is important in young children to reduce the possibility of growth retardation, tetany, and seizures. Next-generation sequencing such as whole-exome or whole-genome sequencing provides a practical tool for the early diagnosis and improvement of GS prognosis. Further whole-genome sequencing is expected to reveal more variants in SLC123A among GS patients with single heterozygous mutations.
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Affiliation(s)
- Lingxia Zhang
- Department of Nephrology, The Children's Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Ke Huang
- Department of Endocrinology, The Children's Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Shugang Wang
- Chigene (Beijing) Translational Medical Research Center, Yizhuang, China
| | - Haidong Fu
- Department of Nephrology, The Children's Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Jingjing Wang
- Department of Nephrology, The Children's Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Huijun Shen
- Department of Nephrology, The Children's Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Zhihong Lu
- Department of Nephrology, The Children's Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Junyi Chen
- Department of Nephrology, The Children's Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Yu Bao
- Department of Nephrology, The Children's Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Chunyue Feng
- Department of Nephrology, The Children's Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Guanping Dong
- Department of Endocrinology, The Children's Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Jianhua Mao
- Department of Nephrology, The Children's Hospital of Zhejiang University School of Medicine, Hangzhou, China
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Alexandru M, Courbebaisse M, Le Pajolec C, Ménage A, Papon JF, Vargas-Poussou R, Nevoux J, Blanchard A. Investigation of Vestibular Function in Adult Patients with Gitelman Syndrome: Results of an Observational Study. J Clin Med 2020; 9:jcm9113790. [PMID: 33238651 PMCID: PMC7700665 DOI: 10.3390/jcm9113790] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 11/16/2020] [Accepted: 11/21/2020] [Indexed: 12/22/2022] Open
Abstract
Gitelman syndrome (GS) is a rare salt-losing tubulopathy caused by an inactivating mutation in the SLC12A3 gene, encoding the thiazide-sensitive sodium chloride cotransporter (NCC). Patients with GS frequently complain of vertigo, usually attributed to hypovolemia. Because NCC is also located in the endolymphatic sac, we hypothesized that patients with GS might have vestibular dysfunction. Between April 2013 and September 2016, 20 (22%) out of 90 patients followed at the reference center complained of vertigo in the absence of orthostatic hypotension. Sixteen of them were referred to an otology department for investigation of vestibular function. The vertigo was of short duration and triggered in half of them by head rotation. Seven patients (44%) had a vestibular syndrome. Vestibular syndrome was defined: (1) clinically, as nystagmus triggered by the head shaking test (n = 5); and/or (2) paraclinically, as an abnormal video head impulse test (n = 0), abnormal kinetic test (n = 4) and/or abnormal bithermal caloric test (n = 3). Five patients had associated auditory signs (tinnitus, aural fullness or hearing loss). In conclusion, we found a high frequency of vestibular disorder in GS patients suffering from vertigo, suggesting a role of NCC in the inner ear. Referent physicians of these patients should be aware of this extrarenal manifestation that requires specific investigations and treatment.
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Affiliation(s)
- Mihaela Alexandru
- AP-HP, Université Paris Saclay, Hôpital Bicêtre, Service d’Oto-Rhino-Laryngologie, 94270 Le Kremlin-Bicêtre, France; (M.A.); (C.L.P.); (A.M.); (J.-F.P.)
| | - Marie Courbebaisse
- AP-HP, Centre—Université de Paris, Hôpital Européen Georges-Pompidou, Service de Physiologie-Exploration Fonctionnelles Rénales, 75015 Paris, France;
- Faculté de Médecine Paris Descartes, Université de Paris, 75006 Paris, France
- INSERM, U1151-CNRS UMR8253, 75015 Paris, France
| | - Christine Le Pajolec
- AP-HP, Université Paris Saclay, Hôpital Bicêtre, Service d’Oto-Rhino-Laryngologie, 94270 Le Kremlin-Bicêtre, France; (M.A.); (C.L.P.); (A.M.); (J.-F.P.)
| | - Adeline Ménage
- AP-HP, Université Paris Saclay, Hôpital Bicêtre, Service d’Oto-Rhino-Laryngologie, 94270 Le Kremlin-Bicêtre, France; (M.A.); (C.L.P.); (A.M.); (J.-F.P.)
| | - Jean-François Papon
- AP-HP, Université Paris Saclay, Hôpital Bicêtre, Service d’Oto-Rhino-Laryngologie, 94270 Le Kremlin-Bicêtre, France; (M.A.); (C.L.P.); (A.M.); (J.-F.P.)
- Faculté de Médecine, Université Paris-Saclay, F-94275 Le Kremlin-Bicêtre, France
| | - Rosa Vargas-Poussou
- AP-HP, Centre—Université de Paris, Hôpital Européen Georges-Pompidou, Département de Génétique et Biologie Moléculaire, 75015 Paris, France;
- INSERM, UMRS 1138, Centre de Recherche des Cordeliers, 75006 Paris, France
- Centre de Référence des Maladies Rénales Héréditaires de l’Enfant et de l’Adulte (MARHEA), Hôpital Européen Georges-Pompidou, 75015 Paris, France
| | - Jérôme Nevoux
- AP-HP, Université Paris Saclay, Hôpital Bicêtre, Service d’Oto-Rhino-Laryngologie, 94270 Le Kremlin-Bicêtre, France; (M.A.); (C.L.P.); (A.M.); (J.-F.P.)
- Faculté de Médecine, Université Paris-Saclay, F-94275 Le Kremlin-Bicêtre, France
- INSERM, U1120, Institut Pasteur, 75724 Paris CEDEX 15, France
- Correspondence: (J.N.); (A.B.); Tel.: +33-1-4521-3688 (J.N.); +33-1-5609-2913 (A.B.)
| | - Anne Blanchard
- Faculté de Médecine Paris Descartes, Université de Paris, 75006 Paris, France
- INSERM, UMRS 1138, Centre de Recherche des Cordeliers, 75006 Paris, France
- Centre de Référence des Maladies Rénales Héréditaires de l’Enfant et de l’Adulte (MARHEA), Hôpital Européen Georges-Pompidou, 75015 Paris, France
- AP-HP, Hôpital Européen Georges-Pompidou, Centre d’Investigation Clinique 1418, 75015 Paris, France
- Correspondence: (J.N.); (A.B.); Tel.: +33-1-4521-3688 (J.N.); +33-1-5609-2913 (A.B.)
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van der Wijst J, Belge H, Bindels RJM, Devuyst O. Learning Physiology From Inherited Kidney Disorders. Physiol Rev 2019; 99:1575-1653. [PMID: 31215303 DOI: 10.1152/physrev.00008.2018] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The identification of genes causing inherited kidney diseases yielded crucial insights in the molecular basis of disease and improved our understanding of physiological processes that operate in the kidney. Monogenic kidney disorders are caused by mutations in genes coding for a large variety of proteins including receptors, channels and transporters, enzymes, transcription factors, and structural components, operating in specialized cell types that perform highly regulated homeostatic functions. Common variants in some of these genes are also associated with complex traits, as evidenced by genome-wide association studies in the general population. In this review, we discuss how the molecular genetics of inherited disorders affecting different tubular segments of the nephron improved our understanding of various transport processes and of their involvement in homeostasis, while providing novel therapeutic targets. These include inherited disorders causing a dysfunction of the proximal tubule (renal Fanconi syndrome), with emphasis on epithelial differentiation and receptor-mediated endocytosis, or affecting the reabsorption of glucose, the handling of uric acid, and the reabsorption of sodium, calcium, and magnesium along the kidney tubule.
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Affiliation(s)
- Jenny van der Wijst
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
| | - Hendrica Belge
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
| | - René J M Bindels
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
| | - Olivier Devuyst
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
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12
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Miya A, Nakamura A, Kameda H, Nozu K, Miyoshi H, Atsumi T. Gitelman's syndrome with hyperphosphatemia, effectively responding to single oral magnesium oxide administration: A case report. Medicine (Baltimore) 2019; 98:e16408. [PMID: 31305454 PMCID: PMC6641743 DOI: 10.1097/md.0000000000016408] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
RATIONALE The Gitelman's syndrome (GS) is characterized by metabolic alkalosis, hypokalemia, hypomagnesemia, and hypocalciuria. However, the involvement of this deranged electrolyte balance in patients with GS in parathyroid hormone action has not been known. PATIENT CONCERNS We report a 34-year-old woman with muscle weakness and tetany/seizures caused by electrolyte imbalance. She had hyperphosphatemia and hypocalciuric hypocalcemia in addition to severe hypomagnesemia with low potassium in the absence of metabolic alkalosis. We identified 2 heterozygous mutations in the solute carrier family 12 member 3 gene in this case (c.1732G>A, p.Val578Met and c.2537_38delTT, p.846fs) by targeted sequence for all causative genes of salt-losing tubulopathies. DIAGNOSES A diagnosis of GS. Hypocalcemia and hyperphosphatemia were suggested to relate with the secondary obstruction of appropriate parathyroid hormone release following severe hypomagnesemia in GS. INTERVENTIONS She was treated with single oral magnesium oxide administration. OUTCOMES The electrolyte imbalance including hypocalcemia and hyperphosphatemia were resolved with a remission of clinical manifestations. LESSONS These observations, in this case, suggest that even severe hypomagnesemia caused by GS was associated with resistance to appropriate parathyroid hormone secretion. Through this case, we recognize that secondary hypoparathyroidism would be triggered by severe hypomagnesemia in GS.
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Affiliation(s)
- Aika Miya
- Department of Rheumatology, Endocrinology and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo
| | - Akinobu Nakamura
- Department of Rheumatology, Endocrinology and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo
| | - Hiraku Kameda
- Department of Rheumatology, Endocrinology and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo
| | - Kandai Nozu
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe
| | - Hideaki Miyoshi
- Division of Diabetes and Obesity, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Tatsuya Atsumi
- Department of Rheumatology, Endocrinology and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo
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13
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Chen Q, Wu Y, Zhao J, Jia Y, Wang W. A case of hypokalemia and proteinuria with a new mutation in the SLC12A3 Gene. BMC Nephrol 2018; 19:275. [PMID: 30340552 PMCID: PMC6194551 DOI: 10.1186/s12882-018-1083-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 10/08/2018] [Indexed: 12/17/2022] Open
Abstract
Background Gitelman syndrome is an autosomal recessive inherited renal disorder characterized by hypokalemia, hypomagnesemia, and hypocalciuria. Since the symptoms are not severe and laboratory results are not always clear, Gitelman syndrome can go unnoticed by physicians. Here, we report our experiences with a patient that presented with hypokalemia and proteinuria; genetic analysis revealed a new homozygous mutation in the SLC12A3 gene. Case presentation A 47-year-old man presented with hypokalemia and proteinuria. He had come to the hospital with the same symptoms 11 months and 3 years prior. His laboratory tests showed hypokalemia, hypocalciuria, and increased plasma angiotensin-2 activity. His renal pathology was consistent with the development of minimal lesions. Genetic analysis found a new homozygous mutation in exon 6 on the SLC12A3 gene (p.Trp281Arg) in the patient and in his brother; his mother and sister were diagnosed as heterozygous carriers of the same gene mutation. Finally, the patient was diagnosed with Gitelman syndrome. Conclusions This case is the first to report a homozygous mutation in the 841th nucleotide of exon 6 on the SLC12A3 gene (p.Trp281Arg), which may cause Gitelman syndrome. At the same time, this report might stimulate interest in discussing the relationship between different mutations in the SLC12A3 gene and renal pathology.
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Affiliation(s)
- Qin Chen
- Department of Nephrology, Tongde Hospital of Zhejiang Province, Gucui Road, No.234, Hangzhou, 310012, Zhejiang, People's Republic of China.
| | - Yaqin Wu
- Department of Internal Medicine, Cixi Chinese Medical Hospital, Cixi, 315300, Zhejiang, People's Republic of China
| | - Jingya Zhao
- Zhejiang Chinese Medical University, Hangzhou, 310053, Zhejiang, People's Republic of China
| | - Ying Jia
- Zhejiang Chinese Medical University, Hangzhou, 310053, Zhejiang, People's Republic of China
| | - Wei Wang
- Department of Nephrology, Tongde Hospital of Zhejiang Province, Gucui Road, No.234, Hangzhou, 310012, Zhejiang, People's Republic of China
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14
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Chen Y, Zhang Z, Lin X, Pan Q, Zheng F, Li H. A novel compound heterozygous variant of the SLC12A3 gene in Gitelman syndrome pedigree. BMC MEDICAL GENETICS 2018; 19:17. [PMID: 29378538 PMCID: PMC5789536 DOI: 10.1186/s12881-018-0527-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2017] [Accepted: 01/16/2018] [Indexed: 02/07/2023]
Abstract
Background Gitelman syndrome (GS) is an autosomal recessive disorder caused by genic mutations of SLC12A3 (Solute carrier family 12 member 3), which encodes the Na-Cl cotransporter (NCC), and presents with characteristic metabolic abnormalities, including hypokalemia, metabolic alkalosis, hypomagnesemia, and hypocalciuria. In this study, we report a case of a GS pedigree, including analysis of GS-associated gene mutations. Methods We performed next-generation sequencing analysis and Sanger sequencing to explore the SLC12A3 mutations in a GS pedigree that included a 35-year-old female patient with GS and five family members within three generations. Furthermore, we summarized their clinical manifestations and analyzed laboratory parameters related to GS. Results The female proband (the patient with GS) presented with intermittent fatigue and transient periods of tetany, along with significant hypokalemia, hypomagnesemia, and hypocalciuria. All other members of the pedigree had normal laboratory results without obvious GS-related symptoms. Genetic analysis of the SLC12A3 gene identified two novel missense mutations (c.1919A > G, p.N640S in exon 15; c.2522A > G, p.D841G in exon 21) in the patient with GS. Moreover, we demonstrated that her mother, younger maternal uncle, and cousin were carriers of one mutation (c.1919A > G), and her father was the carrier of the other (c.2522A > G). Conclusion This is the first report of these two novel pathogenic variants of SLC12A3 and their contribution to GS. Further functional studies are particularly warranted to explore the underlying molecular mechanisms. Electronic supplementary material The online version of this article (10.1186/s12881-018-0527-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yixin Chen
- Department of Endocrinology, Zhejiang University School of Medicine Sir Run Run Shaw Hospital, 3 East Qing Chun Road, Zhejiang, Hangzhou, 310016, China
| | - Ziyi Zhang
- Department of Endocrinology, Zhejiang University School of Medicine Sir Run Run Shaw Hospital, 3 East Qing Chun Road, Zhejiang, Hangzhou, 310016, China
| | - Xihua Lin
- Department of Endocrinology, Zhejiang University School of Medicine Sir Run Run Shaw Hospital, 3 East Qing Chun Road, Zhejiang, Hangzhou, 310016, China
| | - Qianqian Pan
- Department of Endocrinology, Zhejiang University School of Medicine Sir Run Run Shaw Hospital, 3 East Qing Chun Road, Zhejiang, Hangzhou, 310016, China
| | - Fenping Zheng
- Department of Endocrinology, Zhejiang University School of Medicine Sir Run Run Shaw Hospital, 3 East Qing Chun Road, Zhejiang, Hangzhou, 310016, China
| | - Hong Li
- Department of Endocrinology, Zhejiang University School of Medicine Sir Run Run Shaw Hospital, 3 East Qing Chun Road, Zhejiang, Hangzhou, 310016, China.
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15
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Blanchard A, Bockenhauer D, Bolignano D, Calò LA, Cosyns E, Devuyst O, Ellison DH, Karet Frankl FE, Knoers NVAM, Konrad M, Lin SH, Vargas-Poussou R. Gitelman syndrome: consensus and guidance from a Kidney Disease: Improving Global Outcomes (KDIGO) Controversies Conference. Kidney Int 2017; 91:24-33. [PMID: 28003083 DOI: 10.1016/j.kint.2016.09.046] [Citation(s) in RCA: 180] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Revised: 09/14/2016] [Accepted: 09/28/2016] [Indexed: 12/18/2022]
Abstract
Gitelman syndrome (GS) is a rare, salt-losing tubulopathy characterized by hypokalemic metabolic alkalosis with hypomagnesemia and hypocalciuria. The disease is recessively inherited, caused by inactivating mutations in the SLC12A3 gene that encodes the thiazide-sensitive sodium-chloride cotransporter (NCC). GS is usually detected during adolescence or adulthood, either fortuitously or in association with mild or nonspecific symptoms or both. The disease is characterized by high phenotypic variability and a significant reduction in the quality of life, and it may be associated with severe manifestations. GS is usually managed by a liberal salt intake together with oral magnesium and potassium supplements. A general problem in rare diseases is the lack of high quality evidence to inform diagnosis, prognosis, and management. We report here on the current state of knowledge related to the diagnostic evaluation, follow-up, management, and treatment of GS; identify knowledge gaps; and propose a research agenda to substantiate a number of issues related to GS. This expert consensus statement aims to establish an initial framework to enable clinical auditing and thus improve quality control of care.
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Affiliation(s)
- Anne Blanchard
- Faculté de Médecine, Université Paris Descartes, Sorbonne Paris Cité, Paris, France; Hôpital Européen Georges Pompidou, Assistance Publique Hôpitaux de Paris, Centre d'Investigation Clinique, Paris, France; Centre d'Investigation Clinique 1418, Institut National de la Santé et de la Recherche Médicale, Paris, France; UMR 970, Institut National de la Santé et de la Recherche Médicale, Paris, France
| | - Detlef Bockenhauer
- Centre for Nephrology, University College London, London, UK; Great Ormond Street Hospital for Children National Health Service Foundation Trust, London, UK
| | - Davide Bolignano
- Institute of Clinical Physiology, National Research Council, Reggio, Calabria, Italy
| | - Lorenzo A Calò
- Department of Medicine, Nephrology, University of Padova, Padova, Italy
| | | | - Olivier Devuyst
- Institute of Physiology, University of Zurich, Zurich, Switzerland.
| | - David H Ellison
- Division of Nephrology and Hypertension, Oregon Health and Science University, Veterans Affairs Portland Health Care System, Portland, Oregon, USA
| | - Fiona E Karet Frankl
- Department of Medical Genetics, University of Cambridge and Cambridge University Hospitals National Health Service Trust, Cambridge, UK; Division of Renal Medicine, University of Cambridge and Cambridge University Hospitals National Health Service Trust, Cambridge, UK
| | - Nine V A M Knoers
- Department of Genetics, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht, The Netherlands.
| | - Martin Konrad
- Department of General Pediatrics, University Children's Hospital, Münster, Germany
| | - Shih-Hua Lin
- Division of Nephrology, Department of Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan; Graduate Institute of Medical Science, National Defense Medical Center, Taipei, Taiwan
| | - 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
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16
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The thiazide sensitive sodium chloride co-transporter NCC is modulated by site-specific ubiquitylation. Sci Rep 2017; 7:12981. [PMID: 29021560 PMCID: PMC5636807 DOI: 10.1038/s41598-017-12819-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 09/14/2017] [Indexed: 01/31/2023] Open
Abstract
The renal sodium chloride cotransporter, NCC, in the distal convoluted tubule is important for maintaining body Na+ and K+ homeostasis. Endogenous NCC is highly ubiquitylated, but the role of individual ubiquitylation sites is not established. Here, we assessed the role of 10 ubiquitylation sites for NCC function. Transient transfections of HEK293 cells with human wildtype (WT) NCC or various K to R mutants identified greater membrane abundance for K706R, K828R and K909R mutants. Relative to WT-NCC, stable tetracycline inducible MDCKI cell lines expressing K706R, K828R and K909R mutants had significantly higher total and phosphorylated NCC levels at the apical plasma membrane under basal conditions. Low chloride stimulation increased membrane abundance of all mutants to similar or greater levels than WT-NCC. Under basal conditions K828R and K909R mutants had less ubiquitylated NCC in the plasma membrane, and all mutants displayed reduced NCC ubiquitylation following low chloride stimulation. Thiazide-sensitive sodium-22 uptakes were elevated in the mutants and internalization from the plasma membrane was significantly less than WT-NCC. K909R had increased half-life, whereas chloroquine or MG132 treatment indicated that K706 and K909 play roles in lysosomal and proteasomal NCC degradation, respectively. In conclusion, site-specific ubiquitylation of NCC plays alternative roles for NCC function.
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17
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Rosenbaek LL, Rizzo F, MacAulay N, Staub O, Fenton RA. Functional assessment of sodium chloride cotransporter NCC mutants in polarized mammalian epithelial cells. Am J Physiol Renal Physiol 2017; 313:F495-F504. [DOI: 10.1152/ajprenal.00088.2017] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 05/03/2017] [Accepted: 05/15/2017] [Indexed: 12/21/2022] Open
Abstract
The thiazide-sensitive sodium chloride cotransporter NCC is important for maintaining serum sodium (Na+) and, indirectly, serum potassium (K+) levels. Functional studies on NCC have used cell lines with native NCC expression, transiently transfected nonpolarized cell lines, or Xenopus laevis oocytes. Here, we developed the use of polarized Madin-Darby canine kidney type I (MDCKI) mammalian epithelial cell lines with tetracycline-inducible human NCC expression to study NCC activity and membrane abundance in the same system. In radiotracer assays, induced cells grown on filters had robust thiazide-sensitive and chloride dependent sodium-22 (22Na) uptake from the apical side. To minimize cost and maximize throughput, assays were modified to use cells grown on plastic. On plastic, cells had similar thiazide-sensitive 22Na uptakes that increased following preincubation of cells in chloride-free solutions. NCC was detected in the plasma membrane, and both membrane abundance and phosphorylation of NCC were increased by incubation in chloride-free solutions. Furthermore, in cells exposed for 15 min to low or high extracellular K+, the levels of phosphorylated NCC increased and decreased, respectively. To demonstrate that the system allows rapid and systematic assessment of mutated NCC, three phosphorylation sites in NCC were mutated, and NCC activity was examined. 22Na fluxes in phosphorylation-deficient mutants were reduced to baseline levels, whereas phosphorylation-mimicking mutants were constitutively active, even without chloride-free stimulation. In conclusion, this system allows the activity, cellular localization, and abundance of wild-type or mutant NCC to be examined in the same polarized mammalian expression system in a rapid, easy, and low-cost fashion.
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Affiliation(s)
- Lena L. Rosenbaek
- InterPrET Center, Department of Biomedicine, Aarhus University, Aarhus, Denmark
- Department of Neuroscience and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Federica Rizzo
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland; and
- National Centre of Competence in Research “Kidney.ch,” Lausanne, Switzerland
| | - Nanna MacAulay
- Department of Neuroscience and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Olivier Staub
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland; and
- National Centre of Competence in Research “Kidney.ch,” Lausanne, Switzerland
| | - Robert A. Fenton
- InterPrET Center, Department of Biomedicine, Aarhus University, Aarhus, Denmark
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18
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Gil-Peña H, Coto E, Santos F, Espino M, Cea Crespo JM, Chantzopoulos G, Komianou F, Gómez J, Alonso B, Iglesias S, Treard C, Vargas-Poussou R. A new SLC12A3 founder mutation (p.Val647Met) in Gitelman's syndrome patients of Roma ancestry. Nefrologia 2017; 37:423-428. [PMID: 28325561 DOI: 10.1016/j.nefro.2017.01.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 01/12/2017] [Accepted: 01/23/2017] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Gitelman's syndrome (GS) is an autosomal recessive disorder caused by mutations in the SLC12A3 gene. GS is characterized by hypokalaemic metabolic alkalosis, hypomagnesemia and hypocalciuria. Most of the reported patients of Roma ancestry are homozygous for an SLC12A3 intron 9 frameshifting mutation (c.1180+1G>T). Some forms of Bartter's syndrome result from mutations in the CLNCKB gene and clinically overlap with GS. OBJECTIVES To characterize a second SLC12A3 mutation in Roma patients negative for the intron 9 variant. METHODS SLC12A3 and CLNCKB genes were analyzed by next-generation sequencing in two Spanish and Greek gypsy patients who were negative for the intron 9 splicing mutation. Sanger sequencing was performed to confirm the putative mutations in patients and family members. RESULTS We identified a missense variant (p.Val647Met, c.1939G>A) in both cases, and both were homozygous for Met. This mutation was also found in three additional patients; two homozygous and one heterozygous compound with the intron 9 splicing mutation. This new SLC12A3 mutation seems to be characteristic of gipsy GS patients and was linked to the same haplotype in all cases, supporting a founder origin. All the patients showed biochemical features characteristic of GS. CONCLUSION We report a second founder mutation among GS patients of Roma ethnic background. The direct screening of this mutation would facilitate the characterization of patients who are negative for the more common intron 9 +1G>T mutation.
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Affiliation(s)
- Helena Gil-Peña
- Dept. Pediatría-RENALTUBE Consortium, Hospital Universitario Central Asturias, Oviedo, Spain.
| | - Eliecer Coto
- Dept. Genética Molecular-Red de Investigación Renal, Hospital Universitario Central Asturias, Oviedo, Spain; Hôpital Européen Georges Pompidou, France
| | - Fernando Santos
- Dept. Pediatría-RENALTUBE Consortium, Hospital Universitario Central Asturias, Oviedo, Spain; Hôpital Européen Georges Pompidou, France
| | | | | | | | | | - Juan Gómez
- Dept. Genética Molecular-Red de Investigación Renal, Hospital Universitario Central Asturias, Oviedo, Spain
| | - Belén Alonso
- Dept. Genética Molecular-Red de Investigación Renal, Hospital Universitario Central Asturias, Oviedo, Spain
| | - Sara Iglesias
- Dept. Genética Molecular-Red de Investigación Renal, Hospital Universitario Central Asturias, Oviedo, Spain
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Cryptic exon activation in SLC12A3 in Gitelman syndrome. J Hum Genet 2016; 62:335-337. [PMID: 27784896 DOI: 10.1038/jhg.2016.129] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Revised: 09/23/2016] [Accepted: 09/26/2016] [Indexed: 11/08/2022]
Abstract
Gitelman syndrome (GS) is an autosomal recessive renal tubulopathy characterized by hypokalemic metabolic alkalosis with hypocalciuria and hypomagnesemia. GS clinical symptoms range from mild weakness to muscular cramps, paralysis or even sudden death as a result of cardiac arrhythmia. GS is caused by loss-of-function mutations in the solute carrier family 12 member 3 (SLC12A3) gene, but molecular mechanisms underlying such a wide range of symptoms are poorly understood. Here we report cryptic exon activation in SLC12A3 intron 12 in a clinically asymptomatic GS, resulting from an intronic mutation c.1669+297 T>G that created a new acceptor splice site. The cryptic exon was sandwiched between the L3 transposon upstream and a mammalian interspersed repeat downstream, possibly contributing to inclusion of the cryptic exon in mature transcripts. The mutation was identified by targeted next-generation sequencing of candidate genes in GS patients with missing pathogenic SLC12A3 alleles. Taken together, this work illustrates the power of next-generation sequencing to identify causal mutations in intronic regions in asymptomatic individuals at risk of developing potentially fatal disease complications, improving clinical management of these cases.
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20
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Mutation profile and treatment of Gitelman syndrome in Chinese patients. Clin Exp Nephrol 2016; 21:293-299. [PMID: 27216017 DOI: 10.1007/s10157-016-1284-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 05/17/2016] [Indexed: 12/23/2022]
Abstract
BACKGROUND Gitelman syndrome (GS) is a rare autosomal recessive disease caused by loss-of-function mutations in the SLC12A3 gene, and is characterized by hypokalemia and metabolic alkalosis. In this study, we aimed to study the genotype, phenotype, and treatment in 42 GS patients, the largest sample size so far in mainland China. METHOD We retrospectively studied the clinical data and genetic characteristics of 42 patients diagnosed with GS in Peking Union Medical College Hospital from 2012 to 2015. Therapeutic efficacy of spironolactone and potassium supplements was also studied retrospectively. RESULTS Eighty-one mutation alleles were found in 42 patients, and total of 52 distinctly different mutation alleles were identified, of which 15 were new mutation alleles. p.Asp486Asn was a hotspot in our series, with the allele frequency being 19.7 % (16/81), and was found in 13 patients (31.0 %). Treatment with spironolactone or potassium supplements alone significantly increased serum potassium concentration by 0.36 ± 0.37 and 0.45 ± 0.35 mmol/l, respectively (both P < 0.05), and combined therapy with spironolactone and potassium increased serum potassium concentration by 0.69 ± 0.64 mmol/l (P < 0.05). CONCLUSIONS 18.5 % (15/81) mutation sites identified in 42 Chinese GS patients are novel. p.Asp486Asn mutation is a hotspot, which is different from the reports from other countries. Spironolactone could moderately elevate serum potassium level, and spironolactone in combination with potassium supplements tended to be more effective.
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Kortenoeven MLA, Pedersen NB, Rosenbaek LL, Fenton RA. Vasopressin regulation of sodium transport in the distal nephron and collecting duct. Am J Physiol Renal Physiol 2015; 309:F280-99. [DOI: 10.1152/ajprenal.00093.2015] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Accepted: 05/27/2015] [Indexed: 12/22/2022] Open
Abstract
Arginine vasopressin (AVP) is released from the posterior pituitary gland during states of hyperosmolality or hypovolemia. AVP is a peptide hormone, with antidiuretic and antinatriuretic properties. It allows the kidneys to increase body water retention predominantly by increasing the cell surface expression of aquaporin water channels in the collecting duct alongside increasing the osmotic driving forces for water reabsorption. The antinatriuretic effects of AVP are mediated by the regulation of sodium transport throughout the distal nephron, from the thick ascending limb through to the collecting duct, which in turn partially facilitates osmotic movement of water. In this review, we will discuss the regulatory role of AVP in sodium transport and summarize the effects of AVP on various molecular targets, including the sodium-potassium-chloride cotransporter NKCC2, the thiazide-sensitive sodium-chloride cotransporter NCC, and the epithelial sodium channel ENaC.
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Affiliation(s)
- M. L. A. Kortenoeven
- Department of Biomedicine and Center for Interactions of Proteins in Epithelial Transport (InterPrET), Aarhus University, Aarhus, Denmark
| | - N. B. Pedersen
- Department of Biology, Faculty of Science, University of Copenhagen, Copenhagen, Denmark; and
| | - L. L. Rosenbaek
- Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - R. A. Fenton
- Department of Biomedicine and Center for Interactions of Proteins in Epithelial Transport (InterPrET), Aarhus University, Aarhus, Denmark
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Wang L, Dong C, Xi YG, Su X. Thiazide-sensitive Na+-Cl- cotransporter: genetic polymorphisms and human diseases. Acta Biochim Biophys Sin (Shanghai) 2015; 47:325-34. [PMID: 25841442 DOI: 10.1093/abbs/gmv020] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2014] [Accepted: 02/26/2015] [Indexed: 12/16/2022] Open
Abstract
The thiazide-sensitive Na(+)-Cl(-) cotransporter (TSC) is responsible for the major sodium chloride reabsorption pathway, which is located in the apical membrane of the epithelial cells of the distal convoluted tubule. TSC is involved in several physiological activities including transepithelial ion absorption and secretion, cell volume regulation, and setting intracellular Cl(-) concentration below or above its electrochemical potential equilibrium. In addition, TSC serves as the target of thiazide-type diuretics that are the first line of therapy for the treatment of hypertension in the clinic, and its mutants are also reported to be associated with the hereditary disease, Gitelman's syndrome. This review aims to summarize the publications with regard to the TSC by focusing on the association between TSC mutants and human hypertension as well as Gitelman's syndrome.
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Affiliation(s)
- Linghong Wang
- Clinical Medical Research Center of the Affiliated Hospital, Inner Mongolia Medical University, Hohhot 010050, China
| | - Chao Dong
- Clinical Medical Research Center of the Affiliated Hospital, Inner Mongolia Medical University, Hohhot 010050, China
| | - Ya-Guang Xi
- Clinical Medical Research Center of the Affiliated Hospital, Inner Mongolia Medical University, Hohhot 010050, China
| | - Xiulan Su
- Clinical Medical Research Center of the Affiliated Hospital, Inner Mongolia Medical University, Hohhot 010050, China
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Abstract
Gitelman syndrome (GS) is a salt-wasting tubulointerstitial disease of autosomal recessive inheritance (OMIM613395) caused by genic mutation of SLC12A3, which codes thiazide-sensitive Na-Cl cotransporter (NCCT) gene. The gene mutation of the majority of GS patients is compound heterozygous. This study analyzes two cases of GS gene mutation and the clinical phenotype. Twenty patients of two GS pedigrees underwent direct sequence alignment of 26 exons of SLC12A3 to spot and locate mutant site. Proband A of Pedigree I had three mutant sites: Arg928Cys, a homozygote, missense mutation, and two homozygous silent mutations, Ala122Ala and Thr465Thr, and 8 members of Pedigree I carried Arg928Cy heterozygous mutation. Proband B of Pedigree II had a homozygote, Ser710X, and a termination codon was spotted, which would inevitably be translated into abridged and defective protein, and 7 members had Ser710X heterozygous mutation. The heterozygous mutation carriers of the two pedigrees often have stimulus-controlled hypokalemia after strenuous exercise. The parents of Proband A are cousins, a case of intermarriage. Both probands show hypokalemia, hypochloraemia, hypocalcinuria, hyperreninemia, and hyperaldosteronemia; Proband A has normal serum magnesium and increased urinary sodium excretion, while Proband B has hypomagnesemia and increased urinary magnesium ion excretion. Both probands have normal or lower blood pressure, weakness and numbness of lower extremities, muscular soreness, and occasional palpitations and chest discomfort. Proband A wearies easily and Proband B has occasional joint numbness and pain. These two homozygous mutations are responsible for the morbidity of two GS families and they show heterogenicity of clinical phenotype.
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Affiliation(s)
- Jiewei Luo
- Department of Traditional Chinese Medicine, Fujian Provincial Hospital, Fujian Medical University, Fuzhou 350001, China
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Corbetta S, Raimondo F, Tedeschi S, Syrèn ML, Rebora P, Savoia A, Baldi L, Bettinelli A, Pitto M. Urinary exosomes in the diagnosis of Gitelman and Bartter syndromes. Nephrol Dial Transplant 2014; 30:621-30. [DOI: 10.1093/ndt/gfu362] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
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Gitelman Syndrome in a School Boy Who Presented with Generalized Convulsion and Had a R642H/R642W Mutation in the SLC12A3 Gene. Case Rep Pediatr 2014; 2014:279389. [PMID: 25140267 PMCID: PMC4124700 DOI: 10.1155/2014/279389] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Revised: 06/06/2014] [Accepted: 06/12/2014] [Indexed: 12/15/2022] Open
Abstract
An 8-year-old Japanese boy presented with a generalized convulsion. He had hypokalemia (serum K 2.4 mEq/L), hypomagnesemia, and metabolic alkalosis (BE 5.7 mmol/L). In addition, his plasma renin activity was elevated. He was tentatively diagnosed with epilepsy on the basis of the electroencephalogram findings and was treated by potassium L-aspartate and carbamazepine to control the hypokalemia and seizure, respectively. However, a year later, the patient continued to have similar abnormal laboratory data. A presumptive diagnosis of Gitelman syndrome (GS) was then made and the patient's peripheral blood mononuclear cells were subjected to sequence analysis of the SLC12A3 gene, which encodes a thiazide-sensitive sodium-chloride cotransporter. The patient was found to have compound heterozygous mutations, namely, R642H inherited from his father and R642W inherited from his mother. Thus, if a patient shows persistent hypokalemia and metabolic alkalosis, GS must be considered, even if the patient exhibits atypical clinical symptoms.
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Pham PCT, Pham PAT, Pham SV, Pham PTT, Pham PMT, Pham PTT. Hypomagnesemia: a clinical perspective. Int J Nephrol Renovasc Dis 2014; 7:219-30. [PMID: 24966690 PMCID: PMC4062555 DOI: 10.2147/ijnrd.s42054] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Although magnesium is involved in a wide spectrum of vital functions in normal human physiology, the significance of hypomagnesemia and necessity for its treatment are under-recognized and underappreciated in clinical practice. In the current review, we first present an overview of the clinical significance of hypomagnesemia and normal magnesium metabolism, with a focus on renal magnesium handling. Subsequently, we review the literature for both congenital and acquired hypomagnesemic conditions that affect the various steps in normal magnesium metabolism. Finally, we present an approach to the routine evaluation and suggested management of hypomagnesemia.
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Affiliation(s)
| | - Phuong-Anh T Pham
- Veterans Administration Central California Health Care System, Fresno, CA, USA
| | - Son V Pham
- South Texas Veterans Health Care System and University of Texas Health Science Center, San Antonio, TX, USA
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27
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A labor- and cost-effective non-optical semiconductor (Ion Torrent) next-generation sequencing of the SLC12A3 and CLCNKA/B genes in Gitelman's syndrome patients. J Hum Genet 2014; 59:376-80. [PMID: 24830959 DOI: 10.1038/jhg.2014.37] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Revised: 03/29/2014] [Accepted: 04/17/2014] [Indexed: 12/22/2022]
Abstract
Gitelman's syndrome (GS) is a rare recessive disorder caused by mutations in the renal salt-handling genes SLC12A3 and CLCNKB. Our aim was to develop a next-generation sequencing (NGS) procedure for these genes based on two-tubes multiplex amplification of DNA pools and semiconductor sequencing with the Ion Torrent Personal Genome Machine (PGM). We created one pool with DNA from 20 GS patients previously Sanger sequenced for the coding exons of SLC12A3. A total of 13 mutations present in 11 of these patients were used as control variants to validate the NGS procedure. The full coding sequence of SLC12A3, CLCNKB and CLCNKA was amplified in only two Ampliseq tubes and processed and sequenced with the PGM. Large SLC12A3 and CLCNKB deletions were ascertained through multiplex ligation-dependent probe amplification in some patients. With the exception of the SLC12A3 exon 9, all the amplicons were successfully read and 12 of the 13 control variants were detected. The analysis of CLCNKB showed four putative mutations in the GS pool that were further assigned to specific patients. Two patients were heterozygous compounds for a single-nucleotide mutation and a large deletion at SLC12A3 or CLCNKB. We reported a NGS procedure that would facilitate the rapid and cost-effective large-scale screening of the three renal salt-handling genes. In addition to characterize the mutational spectrum of GS patients, the described procedure would facilitate the rapid and cost-effective screening of these genes at a population scale.
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Piala AT, Moon TM, Akella R, He H, Cobb MH, Goldsmith EJ. Chloride sensing by WNK1 involves inhibition of autophosphorylation. Sci Signal 2014; 7:ra41. [PMID: 24803536 DOI: 10.1126/scisignal.2005050] [Citation(s) in RCA: 279] [Impact Index Per Article: 27.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
WNK1 [with no lysine (K)] is a serine-threonine kinase associated with a form of familial hypertension. WNK1 is at the top of a kinase cascade, leading to phosphorylation of several cotransporters, in particular those transporting sodium, potassium, and chloride (NKCC), sodium and chloride (NCC), and potassium and chloride (KCC). The responsiveness of NKCC, NCC, and KCC to changes in extracellular chloride parallels their phosphorylation state, provoking the proposal that these transporters are controlled by a chloride-sensitive protein kinase. We found that chloride stabilizes the inactive conformation of WNK1, preventing kinase autophosphorylation and activation. Crystallographic studies of inactive WNK1 in the presence of chloride revealed that chloride binds directly to the catalytic site, providing a basis for the unique position of the catalytic lysine. Mutagenesis of the chloride-binding site rendered the kinase less sensitive to inhibition of autophosphorylation by chloride, validating the binding site. Thus, these data suggest that WNK1 functions as a chloride sensor through direct binding of a regulatory chloride ion to the active site, which inhibits autophosphorylation.
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Affiliation(s)
- Alexander T Piala
- 1Department of Biophysics, The University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
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29
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Genetic predictors of thiazide-induced serum potassium changes in nondiabetic hypertensive patients. Hypertens Res 2014; 37:759-64. [PMID: 24694645 DOI: 10.1038/hr.2014.74] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Revised: 12/01/2013] [Accepted: 01/25/2014] [Indexed: 12/17/2022]
Abstract
Thiazide diuretics are associated with an increased risk of hypokalemia. However, pharmacogenetic markers of thiazide-induced changes in serum potassium are not well studied. The aim of this study was to investigate possible predictors of serum potassium changes after thiazide treatment. Nondiabetic hypertensive patients with a systolic blood pressure of ⩾140 or a diastolic blood pressure of ⩾90 mm Hg were enrolled in our study. After 2 weeks of lifestyle modification and diet instruction, patients with persistently elevated blood pressure were given 50 mg of hydrochlorothiazide every morning for 2 weeks. Twenty single-nucleotide polymorphism (SNP) markers were selected from two candidate genes, SLC12A3 and WNK1. Serum potassium levels were checked before and after hydrochlorothiazide treatment. A total of 75 patients eventually qualified for enrollment in our study. They received 50 mg of hydrochlorothiazide every morning for 2 weeks. Six SNPs in WNK1 (rs11064524, rs4980973, rs12581940, rs880054, rs953361, and rs10849582) were correlated with decreases in serum potassium. None of the SLC12A3 polymorphisms were correlated with decreases in serum potassium. After Bonferroni's correction, only rs4980973 was correlated with decreases in serum potassium (corrected P=0.014). Multivariate stepwise linear regression analysis revealed that the changes in serum potassium levels were independently associated with the baseline potassium level (β=-0.587, 95% confidence interval=-0.875--0.299, P=0.0001) and WNK1 rs4980973 (A/A and A/G vs. G/G, β=-0.418, 95% confidence interval=-0.598--0.237, P=0.00002). In conclusion, the baseline potassium level and the WNK1 rs4980973 polymorphism were independent predictors of decreases in serum potassium after short-term hydrochlorothiazide treatment in nondiabetic hypertensive patients.
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30
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Rosenbaek LL, Kortenoeven MLA, Aroankins TS, Fenton RA. Phosphorylation decreases ubiquitylation of the thiazide-sensitive cotransporter NCC and subsequent clathrin-mediated endocytosis. J Biol Chem 2014; 289:13347-61. [PMID: 24668812 DOI: 10.1074/jbc.m113.543710] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The thiazide-sensitive sodium chloride cotransporter, NCC, is the major NaCl transport protein in the distal convoluted tubule (DCT). The transport activity of NCC can be regulated by phosphorylation, but knowledge of modulation of NCC trafficking by phosphorylation is limited. In this study, we generated novel tetracycline-inducible Madin-Darby canine kidney type I (MDCKI) cell lines expressing NCC to examine the role of NCC phosphorylation and ubiquitylation on NCC endocytosis. In MDCKI-NCC cells, NCC was highly glycosylated at molecular weights consistent with NCC monomers and dimers. NCC constitutively cycles to the apical plasma membrane of MDCKI-NCC cells, with 20-30% of the membrane pool of NCC internalized within 30 min. The use of dynasore, PitStop2, methyl-β-cyclodextrin, nystatin, and filipin (specific inhibitors of either clathrin-dependent or -independent endocytosis) demonstrated that NCC is internalized via a clathrin-mediated pathway. Reduction of endocytosis resulted in greater levels of NCC in the plasma membrane. Immunogold electron microscopy confirmed the association of NCC with the clathrin-mediated internalization pathway in rat DCT cells. Compared with controls, inducing phosphorylation of NCC via low chloride treatment or mimicking phosphorylation by replacing Thr-53, Thr-58, and Ser-71 residues with Asp resulted in increased membrane abundance and reduced rates of NCC internalization. NCC ubiquitylation was lowest in the conditions with greatest NCC phosphorylation, thus providing a mechanism for the reduced endocytosis. In conclusion, our data support a model where NCC is constitutively cycled to the plasma membrane, and upon stimulation, it can be phosphorylated to both increase NCC activity and decrease NCC endocytosis, together increasing NaCl transport in the DCT.
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Affiliation(s)
- Lena L Rosenbaek
- From the Department of Biomedicine and Center for Interactions of Proteins in Epithelial Transport, Aarhus University, Aarhus DK-8000, Denmark
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31
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Saroja AO, Naik KR, Khanpet MS. Uncommon dyselectrolytemia complicating Guillain-Barré syndrome. J Neurosci Rural Pract 2013; 4:328-30. [PMID: 24250175 PMCID: PMC3821428 DOI: 10.4103/0976-3147.118794] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Guillain–Barré syndrome (GBS) and hypokalemic paralysis are common causes of acute flaccid quadriparesis and specific therapeutic interventions differ. Simultaneous occurrence of severe hypokalemia in patients with GBS at the time of presentation can cause diagnostic and therapeutic dilemma. Presence of hypomagnesemia with hypokalemia in patients with GBS can be perplexing and pose further challenges. Evaluation for preexisting inherited or other associated metabolic disturbances is needed in the presence of such complex dyselectrolytemia. We report the rare association of GBS with severe hypokalemia and hypomagnesemia in a 41-year-old male presenting with acute flaccid quadriparesis and the therapeutic challenges faced.
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Affiliation(s)
- Aralikatte Onkarappa Saroja
- Department of Neurology, KLE University's Jawaharlal Nehru Medical College and KLES', Dr. Prabhakar Kore Hospital and MRC, Nehrunagar, Belgaum - 590 010, India
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32
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Koçkara AŞ, Candan F, Hüzmeli C, Kayataş M, Alaygut D. Gitelman's syndrome associated with chondrocalcinosis: a case report. Ren Fail 2013; 35:1285-8. [PMID: 24021031 DOI: 10.3109/0886022x.2013.824380] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Gitelman's syndrome (GS) is a rare disease with autosomal recessive trait, characterized by hypokalemia, hypomagnesemia, metabolic alkalosis, hypocalciuria and hyperkinemic hyperaldosteronism. While muscle weakness, tetany, stomachache, nausea and fever are very common, it could sometimes be completely asymptomatic as is the case in our patient. It is generally benign, but some severe complications like growth retardation and, though rare, paralysis and cardiac arrest could also be seen. A 57-year-old male patient sent to our hospital for further examination because of hypokalemia was diagnosed with GS as a result of clinical and laboratory assessments. Potassium and magnesium replacement was started. We are presenting our case seeing that GS is not a syndrome to be overlooked as it bears a risk of severe complications, although it might be asymptomatic until advanced ages.
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Chu PY, Cheng CJ, Wu YC, Fang YW, Chau T, Uchida S, Sasaki S, Yang SS, Lin SH. SPAK deficiency corrects pseudohypoaldosteronism II caused by WNK4 mutation. PLoS One 2013; 8:e72969. [PMID: 24039833 PMCID: PMC3770638 DOI: 10.1371/journal.pone.0072969] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Accepted: 07/14/2013] [Indexed: 01/11/2023] Open
Abstract
Stimulation of the OSR1 (Oxidative stress-responsive kinase-1)/SPAK [STE20 (sterile 20)/SPS1-related proline/alanine-rich kinase]-NCC (Na(+)-Cl(-) cotransporter) signaling cascade plays an important role in the WNK [With-No-Lysine (K)] kinase 4 D561A knock-in mouse model of pseudohypoaldosteronism type II (PHA II) characterized by salt-sensitive hypertension and hyperkalemia. The aim of this study was to investigate the respective roles of Osr1 and Spak in the pathogenesis of PHA II in vivo. Wnk4 (D561A/+) mice were crossed with kidney tubule-specific (KSP) Osr1 knockout (KSP-Osr1 (-/-)) and Spak knockout (Spak (-/-)) mice. Blood pressure, plasma and urine biochemistries, and the relevant protein expression in the kidneys were examined. Wnk4 (D561A/+), KSP-Osr1 (-/-), and Spak (-/-) mice recapitulated the phenotypes of PHA II, Bartter-like syndrome, and Gitelman syndrome, respectively. Wnk4 (D561A/+).KSP-Osr1 (-/-) remained phenotypically PHA II while Wnk4 (D561A/+).Spak (-/-) mice became normotensive and lacked the PHA II phenotype. Phosphorylated Spak and Ncc were similarly increased in both Wnk4 (D561A/+) and Wnk4 (D561A/+).KSP-Osr1 (-/-) mice while phosphorylated Ncc normalized in Wnk4 (D561A/+).Spak (-/-) mice. Furthermore, Wnk4 (D561A/+).KSP-Osr1 (-/-) mice exhibited exaggerated salt excretion in response to thiazide diuretics while Wnk4 (D561A/+).Spak (-/-) mice exhibited normal responses. Wnk4(D561A/+).Spak (-/-).KSP-Osr1 (-/-) triple mutant mice had low blood pressure and diminished phosphorylated Ncc. Both SPAK and OSR1 are important in the maintenance of blood pressure but activation of SPAK-NCC plays the dominant role in PHA II. SPAK may be a therapeutic target for disorders with salt-sensitive hypertension related to WNK4 activation.
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Affiliation(s)
- Pei-Yi Chu
- Graduate Institute of Medical Sciences, National Defense Medical Center, Taipei, Taiwan
| | - Chih-Jen Cheng
- Division of Nephrology, Department of Medicine, Tri-Service General Hospital, Taipei, Taiwan
| | - Yi-Chang Wu
- Taoyuan Armed Forces General Hospital, Taoyuan, Taiwan
| | - Yu-Wei Fang
- Graduate Institute of Medical Sciences, National Defense Medical Center, Taipei, Taiwan
- Division of Nephrology, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan
| | - Tom Chau
- Department of Medicine, Providence St. Vincent Medical Center, Portland, Oregon, United States of America
| | - Shinichi Uchida
- Department of Nephrology, Graduate School of Medicine, Tokyo Medical and Dental University, Tokyo, Japan
| | - Sei Sasaki
- Department of Nephrology, Graduate School of Medicine, Tokyo Medical and Dental University, Tokyo, Japan
| | - Sung-Sen Yang
- Graduate Institute of Medical Sciences, National Defense Medical Center, Taipei, Taiwan
- Division of Nephrology, Department of Medicine, Tri-Service General Hospital, Taipei, Taiwan
- * E-mail: (SSY); (SHL)
| | - Shih-Hua Lin
- Graduate Institute of Medical Sciences, National Defense Medical Center, Taipei, Taiwan
- Division of Nephrology, Department of Medicine, Tri-Service General Hospital, Taipei, Taiwan
- * E-mail: (SSY); (SHL)
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Zhang C, Zhu Y, Huang F, Jiang G, Chang J, Li R. Novel missense mutations of WNK1 in patients with hypokalemic salt-losing tubulopathies. Clin Genet 2012; 83:545-52. [PMID: 22934535 DOI: 10.1111/cge.12008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Revised: 08/28/2012] [Accepted: 08/28/2012] [Indexed: 12/16/2022]
Affiliation(s)
| | - Y Zhu
- Department of Nephrology, Xinhua Hospital, School of Medicine; Shanghai Jiao Tong University; Shanghai; China
| | - F Huang
- Department of Nephrology, Xinhua Hospital, School of Medicine; Shanghai Jiao Tong University; Shanghai; China
| | - G Jiang
- Department of Nephrology, Xinhua Hospital, School of Medicine; Shanghai Jiao Tong University; Shanghai; China
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Rosenbaek LL, Assentoft M, Pedersen NB, MacAulay N, Fenton RA. Characterization of a novel phosphorylation site in the sodium-chloride cotransporter, NCC. J Physiol 2012; 590:6121-39. [PMID: 22966159 DOI: 10.1113/jphysiol.2012.240986] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The sodium-chloride cotransporter, NCC, is essential for renal electrolyte balance. NCC function can be modulated by protein phosphorylation. In this study, we characterized the role and physiological regulation of a novel phosphorylation site in NCC at Ser124 (S124). Novel phospho-specific antibodies targeting pS124-NCC demonstrated a band of 160 kDa in the kidney cortex, but not medulla, which was preabsorbed by a corresponding phosphorylated peptide. Confocal microscopy with kidney tubule segment-specific markers localized pS124-NCC to all distal convoluted tubule cells. Double immunogold electron microscopy demonstrated that pS124-NCC co-localized with total NCC in the apical plasma membrane of distal convoluted tubule cells and intracellular vesicles. Acute treatment of Munich-Wistar rats or vasopressin-deficient Brattleboro rats with the vasopressin type 2 receptor-specific agonist dDAVP significantly increased pS124-NCC abundance, with no changes in total NCC plasma membrane abundance. pS124-NCC levels also increased in abundance in rats after stimulation of the renin-angiotensin-aldosterone system by dietary low sodium intake. In contrast to other NCC phosphorylation sites, the STE20/SPS1-related proline-alanine-rich kinase and oxidative stress-response kinases (SPAK and OSR1) were not able to phosphorylate NCC at S124. Protein kinase arrays identified multiple kinases that were able to bind to the region surrounding S124. Four of these kinases (IRAK2, CDK6/Cyclin D1, NLK and mTOR/FRAP) showed weak but significant phosphorylation activity at S124. In oocytes, (36)Cl uptake studies combined with biochemical analysis showed decreased activity of plasma membrane-associated NCC when replacing S124 with alanine (A) or aspartic acid (D). In novel tetracycline-inducible MDCKII-NCC cell lines, S124A and S124D mutants were able to traffic to the plasma membrane similarly to wildtype NCC.
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Affiliation(s)
- L L Rosenbaek
- Department of Biomedicine, Aarhus University, DK-8000 Aarhus, Denmark
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36
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Perioperative considerations in patients with Gitelman syndrome: a case series. J Clin Anesth 2012; 24:14-8. [DOI: 10.1016/j.jclinane.2011.04.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2010] [Revised: 03/24/2011] [Accepted: 04/20/2011] [Indexed: 12/11/2022]
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37
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Mammen C, Rupps R, Trnka P, Boerkoel CF. Hypothesis: SLC12A3 Polymorphism modifies thiazide hypersensitivity of antenatal Bartter syndrome to thiazide resistance. Eur J Med Genet 2012; 55:96-8. [DOI: 10.1016/j.ejmg.2011.12.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2011] [Accepted: 12/16/2011] [Indexed: 10/14/2022]
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38
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Favre GA, Nau V, Kolb I, Vargas-Poussou R, Hannedouche T, Moulin B. Localization of tubular adaptation to renal sodium loss in Gitelman syndrome. Clin J Am Soc Nephrol 2012; 7:472-8. [PMID: 22241817 DOI: 10.2215/cjn.00940111] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
BACKGROUND AND OBJECTIVES Gitelman syndrome (GS) is a salt-wasting tubulopathy that results from the inactivation of the human thiazide-sensitive sodium chloride cotransporter located in the distal convoluted tubule. Tubular adaptation to renal sodium loss has been described and localized in the distal tubule in experimental models of GS but not in humans with GS. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS The tubular adaptation to renal sodium loss is described. Osmole-free water clearance and endogenous lithium clearance with furosemide infusion are used to compare 7 patients with genetically confirmed GS and 13 control participants. RESULTS Neither endogenous lithium clearance nor osmole-free water clearance disclosed enhanced proximal fluid reabsorption in patients with GS. These patients displayed significantly lower osmole-free water clearance factored by inulin clearance (7.1 ± 1.9 versus 10.1 ± 2.2; P<0.01) and significantly lower fractional sodium reabsorption in the diluting nephron (73.2% ± 7.1% versus 86.1% ± 4.7%; P<0.005), consistent with the inactivation of the thiazide-sensitive sodium chloride cotransporter. The furosemide-induced reduction rate of fractional sodium reabsorption in the diluting segment was higher in patients with GS (75.6% ± 6.1% versus 69.9% ± 3.2%; P<0.039), suggesting that sodium reabsorption would be enhanced in the cortical part of the thick ascending limb of the loop of Henle in patients with GS. CONCLUSIONS These findings suggest that tubular adaptation to renal sodium loss in GS would be devoted to the cortical part of the thick ascending limb of the loop of Henle in humans.
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Novel NCC mutants and functional analysis in a new cohort of patients with Gitelman syndrome. Eur J Hum Genet 2011; 20:263-70. [PMID: 22009145 DOI: 10.1038/ejhg.2011.189] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Gitelman syndrome (GS) is an autosomal recessive disorder characterized by hypokalemic metabolic alkalosis in conjunction with significant hypomagnesemia and hypocalciuria. The GS phenotype is caused by mutations in the solute carrier family 12, member 3 (SLC12A3) gene that encodes the thiazide-sensitive NaCl cotransporter (NCC). We analyzed DNA samples of 163 patients with a clinical suspicion of GS by direct sequencing of all 26 exons of the SLC12A3 gene. In total, 114 different mutations were identified, 31 of which have not been reported before. These novel variants include 3 deletions, 18 missense, 6 splice site and 4 nonsense mutations. We selected seven missense mutations to investigate their effect on NCC activity and plasma membrane localization by using the Xenopus laevis oocyte expression system. The Thr392Ile mutant did not display transport activity (probably class 2 mutation), while the Asn442Ser and Gln1030Arg NCC mutants showed decreased plasma membrane localization and consequently function, likely due to impaired trafficking (class 3 mutation). Even though the NaCl uptake was hampered for NCC mutants Glu121Asp, Pro751Leu, Ser475Cys and Tyr489His, the transporters reached the plasma membrane (class 4 mutation), suggesting an effect on NCC regulation or ion affinity. The present study shows the identification of 38 novel mutations in the SLC12A3 gene and provides insight into the mechanisms that regulate NCC.
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Sinha A, Lněnička P, Basu B, Gulati A, Hari P, Bagga A. Gitelman syndrome: novel mutation and long-term follow-up. Clin Exp Nephrol 2011; 16:306-9. [PMID: 21964762 DOI: 10.1007/s10157-011-0542-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2011] [Accepted: 09/13/2011] [Indexed: 11/24/2022]
Abstract
We report a case of Gitelman syndrome presenting with fatigue, paresthesias, weakness of limbs and neck muscles since 2.5 years of age. Investigations showed hypokalemia and hypomagnesemia with urinary magnesium wasting. Genetic analysis revealed the presence of a novel homozygous mutation in the SLC12A3 gene (c.2879_2883+9ins14bp, p.Val 960 Glu fsx12). Management with potassium and magnesium supplements and spironolactone resulted in a significant improvement in symptoms. Over a follow-up of 11 years, the patient showed satisfactory growth and physical development.
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Affiliation(s)
- Aditi Sinha
- Division of Pediatric Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, 110029, India.
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Balavoine AS, Bataille P, Vanhille P, Azar R, Noël C, Asseman P, Soudan B, Wémeau JL, Vantyghem MC. Phenotype-genotype correlation and follow-up in adult patients with hypokalaemia of renal origin suggesting Gitelman syndrome. Eur J Endocrinol 2011; 165:665-73. [PMID: 21753071 DOI: 10.1530/eje-11-0224] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
INTRODUCTION Gitelman syndrome (GS) is a tubulopathy caused by SLC12A3 gene mutations, which lead to hypokalaemic alkalosis, secondary hyperaldosteronism, hypomagnesaemia and hypocalciuria. AIM The aim of this study was to assess the prevalence of SLC12A3 gene mutations in adult hypokalaemic patients; to compare the phenotype of homozygous, heterozygous and non-mutated patients; and to determine the efficiency of treatment. METHODS Clinical, biological and genetic data were recorded in 26 patients. RESULTS Screening for the SLC12A3 gene detected two mutations in 15 patients (six homozygous and nine compound heterozygous), one mutation in six patients and no mutation in five patients. There was no statistical difference in clinical symptoms at diagnosis between the three groups. Systolic blood pressure tended to be lower in patients with two mutations (P=0.16). Hypertension was unexpectedly detected in four patients. Five patients with two mutated alleles and two with heterozygosity had severe manifestations of GS. Significant differences were observed between the three groups in blood potassium, chloride, magnesium, supine aldosterone, 24 h urine chloride and magnesium levels and in modification of the diet in renal disease. Mean blood potassium levels increased from 2.8 ± 0.3, 3.5 ± 0.5 and 3.2 ± 0.3 before treatment to 3.2 ± 0.5, 3.7 ± 0.6 and 3.7 ± 0.3 mmol/l with treatment in groups with two (P=0.003), one and no mutated alleles respectively. CONCLUSION In adult patients referred for renal hypokalaemia, we confirmed the presence of mutations of the SLC12A3 gene in 80% of cases. GS was more severe in patients with two mutated alleles than in those with one or no mutated alleles. High blood pressure should not rule out the diagnosis, especially in older patients.
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Affiliation(s)
- A S Balavoine
- Service d'Endocrinologie et Maladies Métaboliques, CHRU de Lille, 59037 Lille Cedex, France.
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Vargas-Poussou R, Dahan K, Kahila D, Venisse A, Riveira-Munoz E, Debaix H, Grisart B, Bridoux F, Unwin R, Moulin B, Haymann JP, Vantyghem MC, Rigothier C, Dussol B, Godin M, Nivet H, Dubourg L, Tack I, Gimenez-Roqueplo AP, Houillier P, Blanchard A, Devuyst O, Jeunemaitre X. Spectrum of mutations in Gitelman syndrome. J Am Soc Nephrol 2011; 22:693-703. [PMID: 21415153 DOI: 10.1681/asn.2010090907] [Citation(s) in RCA: 154] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Gitelman's syndrome (GS) is a rare, autosomal recessive, salt-losing tubulopathy caused by mutations in the SLC12A3 gene, which encodes the thiazide-sensitive NaCl cotransporter (NCC). Because 18 to 40% of suspected GS patients carry only one SLC12A3 mutant allele, large genomic rearrangements may account for unidentified mutations. Here, we directly sequenced genomic DNA from a large cohort of 448 unrelated patients suspected of having GS. We found 172 distinct mutations, of which 100 were unreported previously. In 315 patients (70%), we identified two mutations; in 81 patients (18%), we identified one; and in 52 patients (12%), we did not detect a mutation. In 88 patients, we performed a search for large rearrangements by multiplex ligation-dependent probe amplification (MLPA) and found nine deletions and two duplications in 24 of the 51 heterozygous patients. A second technique confirmed each rearrangement. Based on the breakpoints of seven deletions, nonallelic homologous recombination by Alu sequences and nonhomologous end-joining probably favor these intragenic deletions. In summary, missense mutations account for approximately 59% of the mutations in Gitelman's syndrome, and there is a predisposition to large rearrangements (6% of our cases) caused by the presence of repeated sequences within the SLC12A3 gene.
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Affiliation(s)
- Rosa Vargas-Poussou
- Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Service de Génétique, Paris, France.
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Lo YF, Nozu K, Iijima K, Morishita T, Huang CC, Yang SS, Sytwu HK, Fang YW, Tseng MH, Lin SH. Recurrent deep intronic mutations in the SLC12A3 gene responsible for Gitelman's syndrome. Clin J Am Soc Nephrol 2010; 6:630-9. [PMID: 21051746 DOI: 10.2215/cjn.06730810] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
BACKGROUND AND OBJECTIVES Gitelman's syndrome (GS) is an autosomal recessive renal tubular disorder caused by mutations in the SLC12A3 gene encoding the thiazide-sensitive Na(+)-Cl(-) cotransporter (NCC). Despite meticulous sequencing of genomic DNA, approximately one-third of GS patients are negative or heterozygotes for the known mutations. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Because blood leukocytes express NCC mRNA, we evaluate whether deep intronic mutations contribute to GS patients with uniallelic or undetectable SLC12A3 mutations. Twenty-nine patients with GS (men/women = 16/13), including eight negative and 21 uniallelic SLC12A3 mutations from 19 unrelated families, and normal controls were enrolled in an academic medical center. Analysis of cDNA from blood leukocytes, sequencing of the corresponding introns of genomic DNA for abnormal transcript, and analysis of NCC protein expression from renal biopsy were performed. RESULTS We identified nine Taiwan aboriginal patients carrying c.1670-191C→T mutations in intron 13 and 10 nonaboriginal patients carrying c.2548+253C→T mutations in intron 21 from 14 families (14/19). These two mutations undetected in 100 healthy subjects created pseudoexons containing new premature termination codons. Haplotype analysis with markers flanking SLC12A3 revealed that both mutations did not have founder effects. Apical NCC expression in the DCT of renal tissue was markedly diminished in two patients carrying deep intronic mutations. CONCLUSIONS Deep intronic mutations in SLC12A3 causing defective NCC expression can be identified with the RNA-based approach in patients with GS. c.1670-191C→T and c.2548+253C→T are hot spot mutations that can be screened in GS patients with uniallelic or negative SLC12A3 mutations.
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Affiliation(s)
- Yi-Fen Lo
- Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan
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Sarafidis PA, Georgianos PI, Lasaridis AN. Diuretics in clinical practice. Part I: mechanisms of action, pharmacological effects and clinical indications of diuretic compounds. Expert Opin Drug Saf 2010; 9:243-57. [PMID: 20095917 DOI: 10.1517/14740330903499240] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
IMPORTANCE OF THE FIELD Diuretics are among the most important drugs of our therapeutic armamentarium and have been broadly used for > 50 years, providing important help towards the treatment of several diseases. Although all diuretics act primarily by impairing sodium reabsorption in the renal tubules, they differ in their mechanism and site of action and, therefore, in their specific pharmacological properties and clinical indications. Loop diuretics are mainly used for oedematous disorders (i.e., cardiac failure, nephrotic syndrome) and for blood pressure and volume control in renal disease; thiazides and related agents are among the most prescribed drugs for hypertension treatment; aldosterone-blockers are traditionally used for primary or secondary aldosteronism; and other diuretic classes have more specific indications. AREAS COVERED IN THIS REVIEW This article discusses the mechanisms of action, pharmacological effects and clinical indications of the various diuretic classes used in everyday clinical practice, with emphasis on recent knowledge suggesting beneficial effects of certain diuretics on clinical conditions distinct from the traditional indications of these drugs (i.e., heart protection for aldosterone blockers). WHAT THE READER WILL GAIN Reader will gain insights into the effective use of diuretic agents for various medical conditions, representing their established or emerging therapeutic indications. TAKE HOME MESSAGE Knowledge of the pharmacologic properties and mechanisms of action of diuretic agents is a prerequisite for the successful choice and effective clinical use of these compounds.
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Affiliation(s)
- Pantelis A Sarafidis
- 1st Department of Medicine, Section of Nephrology and Hypertension, Aristotle University of Thessaloniki, AHEPA Hospital, Thessaloniki, St Kiriakidi 1, 54636 Thessaloniki, Greece.
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Herrero-Morín JD, Rodríguez J, Coto E, Gil-Peña H, Alvarez V, Espinosa L, Loris C, Gil-Calvo M, Santos F. Gitelman syndrome in Gypsy paediatric patients carrying the same intron 9 + 1 G>T mutation. Clinical features and impact on quality of life. Nephrol Dial Transplant 2010; 26:151-5. [PMID: 20571093 DOI: 10.1093/ndt/gfq352] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Gitelman syndrome is a primary tubular disorder causing hypokalaemic metabolic alkalosis with hypocalciuria. Its prevalence is high in Gypsies, who harbour an identical mutation, intron 9 + 1 G>T, in the SLC12A3 gene. METHODS To better define the Gitelman syndrome in Gypsies, the clinical and biochemical features of 34 Spanish paediatric Gypsy patients were analysed. At diagnosis, symptoms, height and weight as well as serum and urinary biochemical data were collected. During a follow-up of 4.5 ± 2.4 years [X ± standard deviation (SD)], therapy, treatment compliance, symptoms, frequency of hospital admissions and, at the last visit, growth and biochemical work-up of 29 patients followed for at least 6 months were analysed. Quality of life items were also assessed by a questionnaire. RESULTS Muscle cramps (41%) and asthenia (35%) were the most frequent presenting symptoms. Biochemical data at diagnosis were serum K 2.76 ± 0.46 mEq/L, serum Mg 1.32 ± 0.28 mg/dL, blood pH 7.45 ± 0.06, serum bicarbonate 28.2 ± 2.9 mEq/L, urinary calcium/creatinine ratio 0.03 ± 0.04 mg/mg, fractional K excretion 24.4 ± 17.1% and fractional Mg excretion 8.9 ± 8.3%. During follow-up, Mg and K supplements were prescribed to 79 and 86% of patients, respectively; compliance with treatment was good in 35%. Hospital admission rate was 0.03/patient/month. Muscle cramps were the symptom most often referred by the patients (45%) during the follow-up, and 71% of patients considered their health status as excellent or good. Twenty-one patients stated that their disease did not adversely interfere with their mood or social relationships. Height and weight of patients at diagnosis were -0.60 ± 1.17 and -0.49 ± 1.32 SD, respectively, and improved to -0.44 ± 1.28 (P < 0.05) and 0.18 ± 1.79 SD (P < 0.01) at the last visit. CONCLUSIONS Gypsy children with Gitelman syndrome mostly exhibit muscle symptoms and asthenia although the disease is not particularly severe in this ethnic group. Body growth improves with treatment and close follow-up.
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Nozu K, Iijima K, Nozu Y, Ikegami E, Imai T, Fu XJ, Kaito H, Nakanishi K, Yoshikawa N, Matsuo M. A deep intronic mutation in the SLC12A3 gene leads to Gitelman syndrome. Pediatr Res 2009; 66:590-3. [PMID: 19668106 DOI: 10.1203/pdr.0b013e3181b9b4d3] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Many mutations have been detected in the SLC12A3 gene of Gitelman syndrome (GS, OMIM 263800) patients. In previous studies, only one mutant allele was detected in approximately 20 to 41% of patients with GS; however, the exact reason for the nonidentification has not been established. In this study, we used RT-PCR using mRNA to investigate for the first time transcript abnormalities caused by deep intronic mutation. Direct sequencing analysis of leukocyte DNA identified one base insertion in exon 6 (c.818_819insG), but no mutation was detected in another allele. We analyzed RNA extracted from leukocytes and urine sediments and detected unknown sequence containing 238bp between exons 13 and 14. The genomic DNA analysis of intron 13 revealed a single-base substitution (c.1670-191C>T) that creates a new donor splice site within the intron resulting in the inclusion of a novel cryptic exon in mRNA. This is the first report of creation of a splice site by a deep intronic single-nucleotide change in GS and the first report to detect the onset mechanism in a patient with GS and missing mutation in one allele. This molecular onset mechanism may partly explain the poor success rate of mutation detection in both alleles of patients with GS.
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Affiliation(s)
- Kandai Nozu
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan.
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Fava C, Montagnana M, Rosberg L, Burri P, Jönsson A, Wanby P, Wahrenberg H, Hulthén UL, Aurell M, Guidi GC, Melander O. Novel mutations in theSLC12A3gene causing Gitelman's syndrome in Swedes. ACTA ACUST UNITED AC 2009; 18:395-9. [PMID: 17654016 DOI: 10.1080/10425170701400456] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
PURPOSE Gitelman's syndrome (GS) is an inherited autosomal recessive disorder due to loss of function mutations in the SLC12A3 gene encoding the Na-Cl co-transporter (NCCT), the target of thiazide diuretics. The defective function of the NCCT, which normally is expressed in the apical membrane of the distal convolute tubule in the kidney, leads to mild hypotension, hypokalemia, hyperreninemic hyperaldosteronism, mild metabolic alkalosis, hypomagnesemia and hypocalciuria. Up to now, more than 100 mutations of the SLC12A3 gene have been described in GS patients. METHODS We have collected 30 patients from Sweden with a clinical diagnosis of GS and undertaken a mutation screening by SSCP and successive sequencing of the 26 exons and intronic boundaries. Both mutations were identified in most (n = 28, 93%) and at least one mutation was identified in all patients. RESULTS We found 22 different mutations evenly distributed throughout the gene, 11 of which have not been described previously. The new variants include 8 missense mutations (Glu68Lys, His69Asn, Argl45His, Vall53Met, Gly230Asp, Gly342Ala, Val677Leu and Gly867Ser), 1 insertion (c.834_835insG on exon 6) and 2 splice-site mutations (c.2667 + lT>G substitution in splicing donor site after exon 22, c.1569-1G>A substitution in the splicing acceptor site before exon 13). CONCLUSION In Swedish patients with the clinical features of GS, disease-causing mutations in the SLC12A3 gene were identified in most patients. The spectrum of GS mutations is wide making full mutation screening of the SLC12A3 gene necessary to confirm the diagnosis.
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Affiliation(s)
- Cristiano Fava
- Division of Endocrinology, Department of Clinical Sciences, University of Malmö, Malmo, Sweden.
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Qin L, Shao L, Ren H, Wang W, Pan X, Zhang W, Wang Z, Shen P, Chen N. Identification of five novel variants in the thiazide-sensitive NaCl co-transporter gene in Chinese patients with Gitelman syndrome. Nephrology (Carlton) 2009; 14:52-8. [PMID: 19207868 DOI: 10.1111/j.1440-1797.2008.01042.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
AIM Gitelman syndrome (GS) is an autosomal recessive renal tubulopathy characterized by hypokalaemic metabolic alkalosis, significant hypomagnesemia, low urinary calcium, secondary aldosteronism and normal blood pressure. GS is caused by inactivating variants in the SLC12A3 gene, which encodes the thiazide-sensitive NaCl co-transporter. So far, more than 100 variants have been described in the SLC12A3 gene in Gitelman syndrome. METHODS Biochemical parameters in blood and urine were measured and documented. Genomic DNA was extracted from peripheral blood of all patients. Variants were screened for the SLC12A3 and CLCNKB gene by sequencing directly. Reverse-transcription polymerase chain reaction and complementary DNA sequence analysis were performed to confirm deletion or splicing variants. RESULTS We identified 13 variants in the SLC12A3 gene in 13 Chinese patients, including 10 missense substitutions, two splicing variants, and one deletion/insertion variant. Five novel variants were identified for the first time in patients with Gitelman syndrome. We did not find any variants in the CLCNKB gene. A homozygous Thr60Met carrier suffered from hypothyroidism and received thyroxine replacement therapy. CONCLUSION We have identified 13 variants, including five novel variants in the SLC12A3 gene in 13 patients with Gitelman syndrome. T60M is the most frequent variant in our patients. There was no significant correlation between genotype and phenotype in our patients.
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Affiliation(s)
- Ling Qin
- Department of Nephrology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, China
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