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Lee SH, Lee S, Kim H, Kim GH. Pseudo-Gitelman Syndrome Presenting with Hypokalemic Metabolic Alkalosis and Hypocalciuria. Electrolyte Blood Press 2023; 21:72-76. [PMID: 38152600 PMCID: PMC10751206 DOI: 10.5049/ebp.2023.21.2.72] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 09/04/2023] [Accepted: 09/05/2023] [Indexed: 12/29/2023] Open
Abstract
Pseudo-Bartter syndrome is a well-known differential diagnosis that needs to be excluded in cases of normotensive hypokalemic metabolic alkalosis. Pseudo-Bartter syndrome and pseudo-Gitelman syndrome are often collectively referred to as pseudo-Bartter/Gitelman syndrome; however, pseudo-Gitelman syndrome should be considered as a separate entity because Gitelman syndrome is characterized by hypocalciuria and hypomagnesemia, while Bartter syndrome is usually associated with hypercalciuria. Herein, we report the cases of two young adult female patients who presented with severe hypokalemic metabolic alkalosis, hypocalciuria, and hypomagnesemia. Diuretic or laxative abuse and self-induced vomiting were absent, and a chloride deficit and remarkable bicarbonaturia were observed. Initial sequencing studies for SLC12A3, CLCKNB, and KCNJ10 revealed no mutations, and whole-exome sequencing revealed no pathogenic variants. The metabolic alkalosis was saline-responsive in one case, and steroid therapy was necessary in the other to relieve chronic tubulointerstitial nephritis, which was diagnosed with kidney biopsy. A new category of pseudo-Gitelman syndrome should be defined, and various etiologies should be investigated.
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Affiliation(s)
- Seung Heon Lee
- Department of Internal Medicine, Hanyang University College of Medicine, Seoul, Republic of Korea
| | - Sukyung Lee
- Department of Internal Medicine, Pohang St. Mary's Hospital, Pohang, Republic of Korea
| | - Hyunsung Kim
- Department of Pathology, Hanyang University College of Medicine, Seoul, Republic of Korea
| | - Gheun-Ho Kim
- Department of Internal Medicine, Hanyang University College of Medicine, Seoul, Republic of Korea
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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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Claus LR, Snoek R, Knoers NVAM, van Eerde AM. Review of genetic testing in kidney disease patients: Diagnostic yield of single nucleotide variants and copy number variations evaluated across and within kidney phenotype groups. AMERICAN JOURNAL OF MEDICAL GENETICS. PART C, SEMINARS IN MEDICAL GENETICS 2022; 190:358-376. [PMID: 36161467 PMCID: PMC9828643 DOI: 10.1002/ajmg.c.31995] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 07/02/2022] [Accepted: 08/18/2022] [Indexed: 01/29/2023]
Abstract
Genetic kidney disease comprises a diverse group of disorders. These can roughly be divided in the phenotype groups congenital anomalies of the kidney and urinary tract, ciliopathies, glomerulopathies, stone disorders, tubulointerstitial kidney disease, and tubulopathies. Many etiologies can lead to chronic kidney disease that can progress to end-stage kidney disease. Despite each individual disease being rare, together these genetic disorders account for a large proportion of kidney disease cases. With the introduction of massively parallel sequencing, genetic testing has become more accessible, but a comprehensive analysis of the diagnostic yield is lacking. This review gives an overview of the diagnostic yield of genetic testing across and within the full range of kidney disease phenotypes through a systematic literature search that resulted in 115 included articles. Patient, test, and cohort characteristics that can influence the diagnostic yield are highlighted. Detection of copy number variations and their contribution to the diagnostic yield is described for all phenotype groups. Also, the impact of a genetic diagnosis for a patient and family members, which can be diagnostic, therapeutic, and prognostic, is shown through the included articles. This review will allow clinicians to estimate an a priori probability of finding a genetic cause for the kidney disease in their patients.
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Affiliation(s)
- Laura R. Claus
- Department of GeneticsUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - Rozemarijn Snoek
- Department of GeneticsUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - Nine V. A. M. Knoers
- Department of GeneticsUniversity Medical Center GroningenGroningenThe Netherlands
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Iio K, Mori T, Bessho S, Imai Y, Hatanaka M, Omori H, Kouhara H, Chiga M, Sohara E, Uchida S, Kaimori JY. Gitelman syndrome with a novel frameshift variant in SLC12A3 gene accompanied by chronic kidney disease and type 2 diabetes mellitus. CEN Case Rep 2021; 11:191-195. [PMID: 34617250 DOI: 10.1007/s13730-021-00652-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 09/28/2021] [Indexed: 11/28/2022] Open
Abstract
Gitelman syndrome is an autosomal recessive genetic disease caused by pathogenic variants in SLC12A3 resulting in the loss of function of the Na-Cl co-transporter (NCC) in the distal tubules. Hypokalemia and diuretic effects can cause secondary type 2 diabetes and renal function decline. Here, we present the case of a 49-year-old male patient with chronic persistent treatment-resistant hypokalemia for the past 13 years who had been receiving treatment for type 2 diabetes mellitus for 6 years. He was referred to our department due to the presence of urinary protein, impaired renal function, high renin activity, and hyperaldosteronism. Laboratory test results showed hypokalemia, hypomagnesemia, hypocalciuria, and metabolic alkalosis. Using next-generation and Sanger sequencing, we identified a novel stop-gain variant (NM_000339.3:c.137del [p.His47fs]) and a missense variant (NM_000339.3:c.2927C > T [p.Ser976Phe]) in the SLC12A3 gene. This novel pathogenic variant was located at the intracellular N-terminus of the NCC. Based on these findings, the patient was diagnosed with Gitelman syndrome. The use of next-generation sequencing facilitated the exclusion of diseases with similar clinical symptoms.
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Affiliation(s)
- Kenichiro Iio
- Department of Nephrology, National Hospital Organization Osaka Minami Medical Center, 2-1 Kidohigashimachi, Kawachinagano, Osaka, 586-8521, Japan.
| | - Takayasu Mori
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8510, Japan
| | - Saki Bessho
- Department of Nephrology, National Hospital Organization Osaka Minami Medical Center, 2-1 Kidohigashimachi, Kawachinagano, Osaka, 586-8521, Japan
| | - Yosuke Imai
- Department of Nephrology, National Hospital Organization Osaka Minami Medical Center, 2-1 Kidohigashimachi, Kawachinagano, Osaka, 586-8521, Japan
| | - Masaki Hatanaka
- Department of Nephrology, National Hospital Organization Osaka Minami Medical Center, 2-1 Kidohigashimachi, Kawachinagano, Osaka, 586-8521, Japan
| | - Hiroki Omori
- Department of Nephrology, National Hospital Organization Osaka Minami Medical Center, 2-1 Kidohigashimachi, Kawachinagano, Osaka, 586-8521, Japan
| | - Haruhiko Kouhara
- Department of Endocrinology and Metabolism, Osaka Minami Medical Center, 2-1 Kidohigashimachi, Kawachinagano, Osaka, 586-8521, Japan
| | - Motoko Chiga
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8510, Japan
| | - Eisei Sohara
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8510, Japan
| | - Shinichi Uchida
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8510, Japan
| | - Jun-Ya Kaimori
- Department of Inter-Organ Communication Research in Kidney Disease, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, 565-0871, Japan
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