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Toyoda Y, Takada T, Nakayama A, Shinomiya N, Matsuo H. Biochemical characterization of renal hypouricemia-associated mutations in urate transporter genes using human cells. Hum Cell 2024:10.1007/s13577-024-01079-6. [PMID: 38811494 DOI: 10.1007/s13577-024-01079-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2024] [Accepted: 05/13/2024] [Indexed: 05/31/2024]
Affiliation(s)
- Yu Toyoda
- Department of Integrative Physiology and Bio-Nano Medicine, National Defense Medical College, Saitama, Japan
- Department of Pharmacy, The University of Tokyo Hospital, Tokyo, Japan
| | - Tappei Takada
- Department of Pharmacy, The University of Tokyo Hospital, Tokyo, Japan
| | - Akiyoshi Nakayama
- Department of Integrative Physiology and Bio-Nano Medicine, National Defense Medical College, Saitama, Japan
| | - Nariyoshi Shinomiya
- Department of Integrative Physiology and Bio-Nano Medicine, National Defense Medical College, Saitama, Japan
| | - Hirotaka Matsuo
- Department of Integrative Physiology and Bio-Nano Medicine, National Defense Medical College, Saitama, Japan.
- Department of Bioinformation Management, National Defense Medical College Research Institute, Saitama, Japan.
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Quinlivan R, Murphy E, Pula S, Pain A, Brain H, Scopes G, Gjika F, Ahmadouk N, Manole A, Houlden H. Raised CK and acute kidney injury following intense exercise in three patients with a history of exercise intolerance due to homozygous mutations in SLC2A9. Neuromuscul Disord 2024; 34:49-53. [PMID: 38150892 DOI: 10.1016/j.nmd.2023.11.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 11/01/2023] [Accepted: 11/27/2023] [Indexed: 12/29/2023]
Abstract
Acute rhabdomyolysis (AR) leading to acute kidney injury has many underlying etiologies, however, when the primary trigger is exercise, the most usual underlying cause is either a genetic muscle disorder or unaccustomed intense exercise in a healthy individual. Three adult men presented with a history of exercise intolerance and episodes of acute renal impairment following intense exercise, thought to be due to AR in the case of two, and dehydration in one. The baseline serum CK was mildly raised between attacks in all three patients and acutely raised during attacks in two of the three patients. Following referral to a specialized neuromuscular centre, further investigation identified very low serum urate (<12 umol/L). In all three men, genetic studies confirmed homozygous mutations in SLC2A9, which encodes for facilitated glucose transporter member 9 (GLUT9), a major regulator of urate homeostasis. Hereditary hypouricaemia should be considered in people presenting with acute kidney injury related to intense exercise. Serum urate evaluation is a useful screening test best undertaken after recovery.
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Affiliation(s)
- Ros Quinlivan
- MRC Centre for Neuromuscular Disease, UCL Institute of Neurology, National Hospital for Neurology and Neurosurgery, London, UK.
| | - Elaine Murphy
- Charles Dent Metabolic Unit, National Hospital for Neurology and Neurosurgery, Queen Square London, UK
| | - Shpresa Pula
- MRC Centre for Neuromuscular Disease, UCL Institute of Neurology, National Hospital for Neurology and Neurosurgery, London, UK
| | - Alexandra Pain
- Department of Acute and General Medicine, Stoke Mandeville Hospital, Mandeville Road, Aylesbury UK
| | - Henrietta Brain
- Department of Acute and General Medicine, Stoke Mandeville Hospital, Mandeville Road, Aylesbury UK
| | - Grace Scopes
- University of Buckingham, Stoke Mandeville, Aylesbury, UK
| | - Frenki Gjika
- University of Buckingham, Stoke Mandeville, Aylesbury, UK
| | - Naim Ahmadouk
- Department of Acute and General Medicine, Stoke Mandeville Hospital, Mandeville Road, Aylesbury UK
| | - Andreea Manole
- Department of neurogenetics, UCL Institute of Neurology, National hospital for Neurology and Neurosurgery, UK
| | - Henry Houlden
- Department of neurogenetics, UCL Institute of Neurology, National hospital for Neurology and Neurosurgery, UK
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Ichida K. [Uric Acid Metabolism, Uric Acid Transporters and Dysuricemia]. YAKUGAKU ZASSHI 2024; 144:659-674. [PMID: 38825475 DOI: 10.1248/yakushi.23-00217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
Serum urate levels are determined by the balance between uric acid production and uric acid excretion capacity from the kidneys and intestinal tract. Dysuricemia, including hyperuricemia and hypouricemia, develops when the balance shifts towards an increase or a decrease in the uric acid pool. Hyperuricemia is mostly a multifactorial genetic disorder involving several disease susceptibility genes and environmental factors. Hypouricemia, on the other hand, is caused by genetic abnormalities. The main genes involved in dysuricemia are xanthine oxidoreductase, an enzyme that produces uric acid, and the urate transporters urate transporter 1/solute carrier family 22 member 12 (URAT1/SLC22A12), glucose transporter 9/solute carrier family 2 member 9 (GLUT9/SLC2A9) and ATP binding cassette subfamily G member 2 (ABCG2). Deficiency of xanthine oxidoreductase results in xanthinuria, a rare disease with marked hypouricemia. Xanthinuria can be due to a single deficiency of xanthine oxidoreductase or in combination with aldehyde oxidase deficiency as well. The latter is caused by a deficiency in molybdenum cofactor sulfurase, which is responsible for adding sulphur atoms to the molybdenum cofactor required for xanthine oxidoreductase and aldehyde oxidase to exert their action. URAT1/SLC22A12 and GLUT9/SLC2A9 are involved in urate reabsorption and their deficiency leads to renal hypouricemia, a condition that is common in Japanese due to URAT1/SLC22A12 deficiency. On the other hand, ABCG2 is involved in the secretion of urate, and many Japanese have single nucleotide polymorphisms that result in its reduced function, leading to hyperuricemia. In particular, severe dysfunction of ABCG2 leads to hyperuricemia with reduced extrarenal excretion.
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MESH Headings
- Humans
- Hyperuricemia/etiology
- Hyperuricemia/metabolism
- Hyperuricemia/genetics
- Uric Acid/metabolism
- ATP Binding Cassette Transporter, Subfamily G, Member 2/genetics
- ATP Binding Cassette Transporter, Subfamily G, Member 2/metabolism
- Organic Anion Transporters/metabolism
- Organic Anion Transporters/genetics
- Glucose Transport Proteins, Facilitative/metabolism
- Glucose Transport Proteins, Facilitative/genetics
- Neoplasm Proteins/genetics
- Neoplasm Proteins/metabolism
- Xanthine Dehydrogenase/metabolism
- Xanthine Dehydrogenase/genetics
- Xanthine Dehydrogenase/deficiency
- Animals
- Organic Cation Transport Proteins/genetics
- Organic Cation Transport Proteins/metabolism
- Renal Tubular Transport, Inborn Errors/genetics
- Renal Tubular Transport, Inborn Errors/etiology
- Renal Tubular Transport, Inborn Errors/metabolism
- Urinary Calculi/etiology
- Urinary Calculi/metabolism
- Urinary Calculi/genetics
- Metabolism, Inborn Errors
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Affiliation(s)
- Kimiyoshi Ichida
- Department of Pathophysiology, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences
- Division of Kidney and Hypertension, The Jikei University School of Medicine
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Nakayama A, Kurajoh M, Toyoda Y, Takada T, Ichida K, Matsuo H. Dysuricemia. Biomedicines 2023; 11:3169. [PMID: 38137389 PMCID: PMC10740884 DOI: 10.3390/biomedicines11123169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 11/16/2023] [Accepted: 11/21/2023] [Indexed: 12/24/2023] Open
Abstract
Gout results from elevated serum urate (SU) levels, or hyperuricemia, and is a globally widespread and increasingly burdensome disease. Recent studies have illuminated the pathophysiology of gout/hyperuricemia and its epidemiology, diagnosis, treatment, and complications. The genetic involvement of urate transporters and enzymes is also proven. URAT1, a molecular therapeutic target for gout/hyperuricemia, was initially derived from research into hereditary renal hypouricemia (RHUC). RHUC is often accompanied by complications such as exercise-induced acute kidney injury, which indicates the key physiological role of uric acid. Several studies have also revealed its physiological role as both an anti-oxidant and a pro-oxidant, acting as both a scavenger and a generator of reactive oxygen species (ROSs). These discoveries have prompted research interest in SU and xanthine oxidoreductase (XOR), an enzyme that produces both urate and ROSs, as status or progression biomarkers of chronic kidney disease and cardiovascular disease. The notion of "the lower, the better" is therefore incorrect; a better understanding of uric acid handling and metabolism/transport comes from an awareness that excessively high and low levels both cause problems. We summarize here the current body of evidence, demonstrate that uric acid is much more than a metabolic waste product, and finally propose the novel disease concept of "dysuricemia" on the path toward "normouricemia", or optimal SU level, to take advantage of the dual roles of uric acid. Our proposal should help to interpret the spectrum from hypouricemia to hyperuricemia/gout as a single disease category.
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Affiliation(s)
- Akiyoshi Nakayama
- Department of Integrative Physiology and Bio-Nano Medicine, National Defense Medical College, Tokorozawa 359-8513, Japan
| | - Masafumi Kurajoh
- Department of Metabolism, Endocrinology and Molecular Medicine, Graduate School of Medicine, Osaka Metropolitan University, Osaka 545-8585, Japan
| | - Yu Toyoda
- Department of Integrative Physiology and Bio-Nano Medicine, National Defense Medical College, Tokorozawa 359-8513, Japan
- Department of Pharmacy, The University of Tokyo Hospital, Tokyo 113-8655, Japan
| | - Tappei Takada
- Department of Pharmacy, The University of Tokyo Hospital, Tokyo 113-8655, Japan
| | - Kimiyoshi Ichida
- Department of Pathophysiology, Tokyo University of Pharmacy and Life Science, Hachioji 192-0392, Japan
| | - Hirotaka Matsuo
- Department of Integrative Physiology and Bio-Nano Medicine, National Defense Medical College, Tokorozawa 359-8513, Japan
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Perdomo-Ramírez A, Ramos-Trujillo E, Claverie-Martín F. New SLC22A12 (URAT1) Variant Associated with Renal Hypouricemia Identified by Whole-Exome Sequencing Analysis and Bioinformatics Predictions. Genes (Basel) 2023; 14:1823. [PMID: 37761963 PMCID: PMC10530539 DOI: 10.3390/genes14091823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2023] [Revised: 09/14/2023] [Accepted: 09/18/2023] [Indexed: 09/29/2023] Open
Abstract
Renal hypouricemia (RHUC) is a rare hereditary disorder caused by loss-of-function mutations in the SLC22A12 (RHUC type 1) or SLC2A9 (RHUC type 2) genes, encoding urate transporters URAT1 and GLUT9, respectively, that reabsorb urate in the renal proximal tubule. The characteristics of this disorder are low serum urate levels, high renal fractional excretion of urate, and occasional severe complications such as nephrolithiasis and exercise-induced acute renal failure. In this study, we report two Spanish (Caucasian) siblings and a Pakistani boy with clinical characteristics compatible with RHUC. Whole-exome sequencing (WES) analysis identified two homozygous variants: a novel pathogenic SLC22A12 variant, c.1523G>A; p.(S508N), in the two Caucasian siblings and a previously reported SLC2A9 variant, c.646G>A; p.(G216R), in the Pakistani boy. Our findings suggest that these two mutations cause RHUC through loss of urate reabsorption and extend the SLC22A12 mutation spectrum. In addition, this work further emphasizes the importance of WES analysis in clinical settings.
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Affiliation(s)
- Ana Perdomo-Ramírez
- Unidad de Investigación, Hospital Universitario Nuestra Señora de Candelaria, 38010 Santa Cruz de Tenerife, Spain; (A.P.-R.); (E.R.-T.)
| | - Elena Ramos-Trujillo
- Unidad de Investigación, Hospital Universitario Nuestra Señora de Candelaria, 38010 Santa Cruz de Tenerife, Spain; (A.P.-R.); (E.R.-T.)
- Departamento de Medicina Física y Farmacología, Facultad de Ciencias de la Salud, Sección Medicina, Universidad de La Laguna, 38071 Santa Cruz de Tenerife, Spain
| | - Félix Claverie-Martín
- Unidad de Investigación, Hospital Universitario Nuestra Señora de Candelaria, 38010 Santa Cruz de Tenerife, Spain; (A.P.-R.); (E.R.-T.)
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Toyoda Y, Miyata H, Shigesawa R, Matsuo H, Suzuki H, Takada T. SVCT2/SLC23A2 is a sodium-dependent urate transporter: functional properties and practical application. J Biol Chem 2023; 299:104976. [PMID: 37390985 PMCID: PMC10374969 DOI: 10.1016/j.jbc.2023.104976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 05/10/2023] [Accepted: 06/12/2023] [Indexed: 07/02/2023] Open
Abstract
Urate transporters play a pivotal role in urate handling in the human body, but the urate transporters identified to date do not account for all known molecular processes of urate handling, suggesting the presence of latent machineries. We recently showed that a urate transporter SLC2A12 is also a physiologically important exporter of ascorbate (the main form of vitamin C in the body) that would cooperate with an ascorbate importer, sodium-dependent vitamin C transporter 2 (SVCT2). Based on the dual functions of SLC2A12 and cooperativity between SLC2A12 and SVCT2, we hypothesized that SVCT2 might be able to transport urate. To test this proposal, we conducted cell-based analyses using SVCT2-expressing mammalian cells. The results demonstrated that SVCT2 is a novel urate transporter. Vitamin C inhibited SVCT2-mediated urate transport with a half-maximal inhibitory concentration of 36.59 μM, suggesting that the urate transport activity may be sensitive to physiological ascorbate levels in blood. Similar results were obtained for mouse Svct2. Further, using SVCT2 as a sodium-dependent urate importer, we established a cell-based urate efflux assay that will be useful for identification of other novel urate exporters as well as functional characterization of nonsynonymous variants of already-identified urate exporters including ATP-binding cassette transporter G2. While more studies will be needed to elucidate the physiological impact of SVCT2-mediated urate transport, our findings deepen understanding of urate transport machineries.
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Affiliation(s)
- Yu Toyoda
- Department of Pharmacy, The University of Tokyo Hospital, Bunkyo-ku, Tokyo, Japan
| | - Hiroshi Miyata
- Department of Pharmacy, The University of Tokyo Hospital, Bunkyo-ku, Tokyo, Japan
| | - Ryuichiro Shigesawa
- Department of Pharmacy, The University of Tokyo Hospital, Bunkyo-ku, Tokyo, Japan
| | - Hirotaka Matsuo
- Department of Integrative Physiology and Bio-Nano Medicine, National Defense Medical College, Tokorozawa, Saitama, Japan
| | - Hiroshi Suzuki
- Department of Pharmacy, The University of Tokyo Hospital, Bunkyo-ku, Tokyo, Japan
| | - Tappei Takada
- Department of Pharmacy, The University of Tokyo Hospital, Bunkyo-ku, Tokyo, Japan.
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Toyoda Y, Cho SK, Tasic V, Pavelcová K, Bohatá J, Suzuki H, David VA, Yoon J, Pallaiova A, Šaligová J, Nousome D, Cachau R, Winkler CA, Takada T, Stibůrková B. Identification of a dysfunctional exon-skipping splice variant in GLUT9/ SLC2A9 causal for renal hypouricemia type 2. Front Genet 2023; 13:1048330. [PMID: 36733941 PMCID: PMC9887137 DOI: 10.3389/fgene.2022.1048330] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 12/21/2022] [Indexed: 01/18/2023] Open
Abstract
Renal hypouricemia (RHUC) is a pathological condition characterized by extremely low serum urate and overexcretion of urate in the kidney; this inheritable disorder is classified into type 1 and type 2 based on causative genes encoding physiologically-important urate transporters, URAT1 and GLUT9, respectively; however, research on RHUC type 2 is still behind type 1. We herein describe a typical familial case of RHUC type 2 found in a Slovak family with severe hypouricemia and hyperuricosuria. Via clinico-genetic analyses including whole exome sequencing and in vitro functional assays, we identified an intronic GLUT9 variant, c.1419+1G>A, as the causal mutation that could lead the expression of p.Gly431GlufsTer28, a functionally-null variant resulting from exon 11 skipping. The causal relationship was also confirmed in another unrelated Macedonian family with mild hypouricemia. Accordingly, non-coding regions should be also kept in mind during genetic diagnosis for hypouricemia. Our findings provide a better pathogenic understanding of RHUC and pathophysiological importance of GLUT9.
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Affiliation(s)
- Yu Toyoda
- Department of Pharmacy, The University of Tokyo Hospital, Tokyo, Japan
| | - Sung Kweon Cho
- Molecular Genetics Epidemiology Section, Basic Research Laboratory, National Cancer Institute and Frederick National Laboratory for Cancer Research, Frederick, MD, United States,Department of Pharmacology, Ajou University School of Medicine, Suwon, South Korea
| | - Velibor Tasic
- Faculty of Medicine, University Ss. Cyril and Methodius, Skopje, North Macedonia
| | | | | | - Hiroshi Suzuki
- Department of Pharmacy, The University of Tokyo Hospital, Tokyo, Japan
| | - Victor A. David
- Department of Pharmacy, The University of Tokyo Hospital, Tokyo, Japan
| | - Jaeho Yoon
- Cancer and Developmental Biology Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD, United States
| | | | - Jana Šaligová
- Metabolic Clinic, Children’s Faculty Hospital, Košice, Slovakia
| | - Darryl Nousome
- CCR Collaborative Bioinformatics Resource, Center for Cancer Research, National Cancer Institute, Frederick, MD, United States
| | - Raul Cachau
- Integrated Data Science Section, Research Technologies Branch, National Institute of Allergies and Infectious Diseases, Bethesda, MD, United States
| | - Cheryl A. Winkler
- Molecular Genetics Epidemiology Section, Basic Research Laboratory, National Cancer Institute and Frederick National Laboratory for Cancer Research, Frederick, MD, United States
| | - Tappei Takada
- Department of Pharmacy, The University of Tokyo Hospital, Tokyo, Japan
| | - Blanka Stibůrková
- Institute of Rheumatology, Prague, Czechia,Department of Rheumatology, First Faculty of Medicine, Charles University, Prague, Czechia,Department of Pediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital, Prague, Czechia,*Correspondence: Blanka Stibůrková,
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Alhasan K, D'Alessandri-Silva C, Mongia A, Topaloglu R, Tasic V, Filler G. Young Adults With Hereditary Tubular Diseases: Practical Aspects for Adult-Focused Colleagues. Adv Chronic Kidney Dis 2022; 29:292-307. [PMID: 36084976 DOI: 10.1053/j.ackd.2021.11.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 11/07/2021] [Accepted: 11/15/2021] [Indexed: 11/11/2022]
Abstract
Recent advances in the management of kidney tubular diseases have resulted in a significant cohort of adolescents and young adults transitioning from pediatric- to adult-focused care. Most of the patients under adult-focused care have glomerular diseases, whereas rarer tubular diseases form a considerable proportion of pediatric patients. The purpose of this review is to highlight the clinical signs and symptoms of tubular disorders, as well as their diagnostic workup, including laboratory findings and imaging, during young adulthood. We will then discuss more common disorders such as cystinosis, cystinuria, distal kidney tubular acidosis, congenital nephrogenic diabetes insipidus, Dent disease, rickets, hypercalciuria, and syndromes such as Bartter, Fanconi, Gitelman, Liddle, and Lowe. This review is a practical guide on the diagnostic and therapeutic approach of tubular conditions affecting young adults who are transitioning to adult-focused care.
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Affiliation(s)
- Khalid Alhasan
- Department of Pediatrics, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Cynthia D'Alessandri-Silva
- Department of Pediatrics, University of Connecticut School of Medicine, Farmington, and Nephrology, Connecticut Children's Medical Center, Hartford, CT
| | - Anil Mongia
- Department of Pediatrics, SUNY Downstate Medical Center, Brooklyn, NY
| | - Rezan Topaloglu
- Department of Paediatrics, Division of Pediatric Nephrology, Hacettepe University School of Medicine, Ankara, Turkey
| | - Velibor Tasic
- University Children's Hospital, Medical School, Skopje, North Macedonia
| | - Guido Filler
- Department of Paediatrics, Division of Pediatric Nephrology, Western University, London, ON, Canada; Department of Medicine, Western University, London, ON, Canada; Department of Pathology and Laboratory Medicine, Western University, London, ON, Canada.
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9
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Otani N, Ouchi M, Misawa K, Hisatome I, Anzai N. Hypouricemia and Urate Transporters. Biomedicines 2022; 10:biomedicines10030652. [PMID: 35327453 PMCID: PMC8945357 DOI: 10.3390/biomedicines10030652] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 03/09/2022] [Accepted: 03/10/2022] [Indexed: 02/07/2023] Open
Abstract
Hypouricemia is recognized as a rare disorder, defined as a serum uric acid level of 2.0 mg/dL or less. Hypouricemia is divided into an overexcretion type and an underproduction type. The former typical disease is xanthinuria, and the latter is renal hypouricemia (RHUC). The frequency of nephrogenic hypouricemia due to a deficiency of URAT1 is high in Japan, accounting for most asymptomatic and persistent cases of hypouricemia. RHUC results in a high risk of exercise-induced acute kidney injury and urolithiasis. It is vital to promote research on RHUC, as this will lead not only to the elucidation of its pathophysiology but also to the development of new treatments for gout and hyperuricemia.
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Affiliation(s)
- Naoyuki Otani
- Department of Clinical Pharmacology and Therapeutics, Faculty of Medicine, Oita University, Yufu 879-5593, Oita, Japan;
| | - Motoshi Ouchi
- Department of Pharmacology and Toxicology, Dokkyo Medical University School of Medicine, Mibu 321-0293, Tochigi, Japan;
| | - Kazuharu Misawa
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Kanagawa, Japan;
| | - Ichiro Hisatome
- Yonago Medical Center, National Hospital Organization, Yonago 683-0006, Tottori, Japan;
- Department of Genetic Medicine and Regenerative Therapeutics, Institute of Regenerative Medicine and Biofunction, Graduate School of Medical Sciences, Tottori University, Yonago 680-8550, Tottori, Japan
| | - Naohiko Anzai
- Department of Pharmacology, Chiba University Graduate School of Medicine, Chiba 260-8670, Chiba, Japan
- Correspondence:
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Renal Hypouricemia 1: Rare Disorder as Common Disease in Eastern Slovakia Roma Population. Biomedicines 2021; 9:biomedicines9111607. [PMID: 34829836 PMCID: PMC8615432 DOI: 10.3390/biomedicines9111607] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 10/27/2021] [Accepted: 10/30/2021] [Indexed: 11/17/2022] Open
Abstract
Renal hypouricemia (RHUC) is caused by an inherited defect in the main reabsorption system of uric acid, SLC22A12 (URAT1) and SLC2A9 (GLUT9). RHUC is characterized by a decreased serum uric acid concentration and an increase in its excreted fraction. Patients suffer from hypouricemia, hyperuricosuria, urolithiasis, and even acute kidney injury. We report clinical, biochemical, and genetic findings in a cohort recruited from the Košice region of Slovakia consisting of 27 subjects with hypouricemia and relatives from 11 families, 10 of whom were of Roma ethnicity. We amplified, directly sequenced, and analyzed all coding regions and exon–intron boundaries of the SLC22A12 and SLC2A9 genes. Sequence analysis identified dysfunctional variants c.1245_1253del and c.1400C>T in the SLC22A12 gene, but no other causal allelic variants were found. One heterozygote and one homozygote for c.1245_1253del, nine heterozygotes and one homozygote for c.1400C>T, and two compound heterozygotes for c.1400C>T and c.1245_1253del were found in a total of 14 subjects. Our result confirms the prevalence of dysfunctional URAT1 variants in Roma subjects based on analyses in Slovak, Czech, and Spanish cohorts, and for the first time in a Macedonian Roma cohort. Although RHUC1 is a rare inherited disease, the frequency of URAT1-associated variants indicates that this disease is underdiagnosed. Our findings illustrate that there are common dysfunctional URAT1 allelic variants in the general Roma population that should be routinely considered in clinical practice as part of the diagnosis of Roma patients with hypouricemia and hyperuricosuria exhibiting clinical signs such as urolithiasis, nephrolithiasis, and acute kidney injury.
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Kawamura Y, Nakayama A, Shimizu S, Toyoda Y, Nishida Y, Hishida A, Katsuura-Kamano S, Shibuya K, Tamura T, Kawaguchi M, Suzuki S, Iwasawa S, Nakashima H, Ibusuki R, Uemura H, Hara M, Takeuchi K, Takada T, Tsunoda M, Arisawa K, Takezaki T, Tanaka K, Ichida K, Wakai K, Shinomiya N, Matsuo H. A Proposal for Practical Diagnosis of Renal Hypouricemia: Evidenced from Genetic Studies of Nonfunctional Variants of URAT1/SLC22A12 among 30,685 Japanese Individuals. Biomedicines 2021; 9:biomedicines9081012. [PMID: 34440216 PMCID: PMC8393673 DOI: 10.3390/biomedicines9081012] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 08/06/2021] [Accepted: 08/09/2021] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Renal hypouricemia (RHUC) is characterized by a low serum uric acid (SUA) level and high fractional excretion of uric acid (FEUA). Further studies on FEUA in hypouricemic individuals are needed for a more accurate diagnosis of RHUC. METHODS In 30,685 Japanese health-examination participants, we genotyped the two most common nonfunctional variants of URAT1 (NFV-URAT1), W258X (rs121907892) and R90H (rs121907896), in 1040 hypouricemic individuals (SUA ≤ 3.0 mg/dL) and 2240 individuals with FEUA data. The effects of NFV-URAT1 on FEUA and SUA were also investigated using linear and multiple regression analyses. RESULTS Frequency of hypouricemic individuals (SUA ≤ 3.0 mg/dL) was 0.97% (male) and 6.94% (female) among 30,685 participants. High frequencies of those having at least one allele of NFV-URAT1 were observed in 1040 hypouricemic individuals. Furthermore, NFV-URAT1 significantly increased FEUA and decreased SUA, enabling FEUA and SUA levels to be estimated. Conversely, FEUA and SUA data of hypouricemic individuals are revealed to be useful to predict the number of NFV-URAT1. CONCLUSIONS Our findings reveal that specific patterns of FEUA and SUA data assist with predicting the number of nonfunctional variants of causative genes for RHUC, and can also be useful for practical diagnosis of RHUC even before genetic tests.
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Affiliation(s)
- Yusuke Kawamura
- Department of Integrative Physiology and Bio-Nano Medicine, National Defense Medical College, Tokorozawa 359-8513, Japan; (Y.K.); (A.N.); (S.S.); (Y.T.); (M.K.); (N.S.)
| | - Akiyoshi Nakayama
- Department of Integrative Physiology and Bio-Nano Medicine, National Defense Medical College, Tokorozawa 359-8513, Japan; (Y.K.); (A.N.); (S.S.); (Y.T.); (M.K.); (N.S.)
| | - Seiko Shimizu
- Department of Integrative Physiology and Bio-Nano Medicine, National Defense Medical College, Tokorozawa 359-8513, Japan; (Y.K.); (A.N.); (S.S.); (Y.T.); (M.K.); (N.S.)
| | - Yu Toyoda
- Department of Integrative Physiology and Bio-Nano Medicine, National Defense Medical College, Tokorozawa 359-8513, Japan; (Y.K.); (A.N.); (S.S.); (Y.T.); (M.K.); (N.S.)
- Department of Pharmacy, Faculty of Medicine, The University of Tokyo Hospital, The University of Tokyo, Tokyo 113-8655, Japan;
| | - Yuichiro Nishida
- Department of Preventive Medicine, Faculty of Medicine, Saga University, Saga 849-8501, Japan; (Y.N.); (M.H.); (K.T.)
| | - Asahi Hishida
- Department of Preventive Medicine, Graduate School of Medicine, Nagoya University, Nagoya 466-8550, Japan; (A.H.); (T.T.); (K.T.); (K.W.)
| | - Sakurako Katsuura-Kamano
- Department of Preventive Medicine, Graduate School of Biomedical Sciences, Tokushima University, Tokushima 770-8503, Japan; (S.K.-K.); (K.A.)
| | - Kenichi Shibuya
- Department of International Island and Community Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544, Japan; (K.S.); (R.I.); (T.T.)
- Department of Emergency and Intensive Care Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544, Japan
| | - Takashi Tamura
- Department of Preventive Medicine, Graduate School of Medicine, Nagoya University, Nagoya 466-8550, Japan; (A.H.); (T.T.); (K.T.); (K.W.)
| | - Makoto Kawaguchi
- Department of Integrative Physiology and Bio-Nano Medicine, National Defense Medical College, Tokorozawa 359-8513, Japan; (Y.K.); (A.N.); (S.S.); (Y.T.); (M.K.); (N.S.)
| | - Satoko Suzuki
- Department of Preventive Medicine and Public Health, National Defense Medical College, Tokorozawa 359-8513, Japan; (S.S.); (S.I.); (H.N.); (M.T.)
| | - Satoko Iwasawa
- Department of Preventive Medicine and Public Health, National Defense Medical College, Tokorozawa 359-8513, Japan; (S.S.); (S.I.); (H.N.); (M.T.)
| | - Hiroshi Nakashima
- Department of Preventive Medicine and Public Health, National Defense Medical College, Tokorozawa 359-8513, Japan; (S.S.); (S.I.); (H.N.); (M.T.)
| | - Rie Ibusuki
- Department of International Island and Community Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544, Japan; (K.S.); (R.I.); (T.T.)
| | - Hirokazu Uemura
- Department of Health and Welfare System, College of Nursing Art and Science, University of Hyogo, Akashi 673-8588, Japan;
| | - Megumi Hara
- Department of Preventive Medicine, Faculty of Medicine, Saga University, Saga 849-8501, Japan; (Y.N.); (M.H.); (K.T.)
| | - Kenji Takeuchi
- Department of Preventive Medicine, Graduate School of Medicine, Nagoya University, Nagoya 466-8550, Japan; (A.H.); (T.T.); (K.T.); (K.W.)
| | - Tappei Takada
- Department of Pharmacy, Faculty of Medicine, The University of Tokyo Hospital, The University of Tokyo, Tokyo 113-8655, Japan;
| | - Masashi Tsunoda
- Department of Preventive Medicine and Public Health, National Defense Medical College, Tokorozawa 359-8513, Japan; (S.S.); (S.I.); (H.N.); (M.T.)
| | - Kokichi Arisawa
- Department of Preventive Medicine, Graduate School of Biomedical Sciences, Tokushima University, Tokushima 770-8503, Japan; (S.K.-K.); (K.A.)
| | - Toshiro Takezaki
- Department of International Island and Community Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544, Japan; (K.S.); (R.I.); (T.T.)
| | - Keitaro Tanaka
- Department of Preventive Medicine, Faculty of Medicine, Saga University, Saga 849-8501, Japan; (Y.N.); (M.H.); (K.T.)
| | - Kimiyoshi Ichida
- Department of Pathophysiology, Tokyo University of Pharmacy and Life Sciences, Tokyo 192-0392, Japan;
- Division of Kidney and Hypertension, Department of Internal Medicine, Jikei University School of Medicine, Tokyo 105-8461, Japan
| | - Kenji Wakai
- Department of Preventive Medicine, Graduate School of Medicine, Nagoya University, Nagoya 466-8550, Japan; (A.H.); (T.T.); (K.T.); (K.W.)
| | - Nariyoshi Shinomiya
- Department of Integrative Physiology and Bio-Nano Medicine, National Defense Medical College, Tokorozawa 359-8513, Japan; (Y.K.); (A.N.); (S.S.); (Y.T.); (M.K.); (N.S.)
| | - Hirotaka Matsuo
- Department of Integrative Physiology and Bio-Nano Medicine, National Defense Medical College, Tokorozawa 359-8513, Japan; (Y.K.); (A.N.); (S.S.); (Y.T.); (M.K.); (N.S.)
- Correspondence: ; Tel.: +81-4-2995-1482
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12
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Nakayama A, Kawamura Y, Toyoda Y, Shimizu S, Kawaguchi M, Aoki Y, Takeuchi K, Okada R, Kubo Y, Imakiire T, Iwasawa S, Nakashima H, Tsunoda M, Ito K, Kumagai H, Takada T, Ichida K, Shinomiya N, Matsuo H. Genetic-epidemiological analysis of hypouricemia from 4,993 Japanese on nonfunctional variants of URAT1/SLC22A12 gene. Rheumatology (Oxford) 2021; 61:1276-1281. [PMID: 34255816 PMCID: PMC8889275 DOI: 10.1093/rheumatology/keab545] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 07/06/2021] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVES Up to 0.3% of Japanese have hypouricemia. Most cases appear to result from a hereditary disease, renal hypouricemia (RHUC), which causes exercise-induced acute kidney injury and urolithiasis. However, to what extent RHUC accounts for hypouricemia is not known. We therefore investigated its frequency and evaluated its risks by genotyping a general Japanese population. METHODS A cohort of 4,993 Japanese was examined by genotyping the nonfunctional variants R90H (rs121907896) and W258X (rs121907892) of URAT1/SLC22A12, the two commonest causative variants of RHUC in Japanese. RESULTS Participants' fractional excretion of uric acid and risk allele frequencies markedly increased at lower SUA levels. Ten participants (0.200%) had a serum uric acid (SUA) level of ≤ 2.0 mg/dl and nine had R90H or W258X, likely to have RHUC. Logistic regression analysis revealed these URAT1 variants to be significantly and independently associated with the risk of hypouricemia and mild hypouricemia (SUA ≤ 3.0 mg/dl) as well as sex, age, and BMI, but these URAT1 variants were the only risks in the hypouricemia population (SUA ≤ 2.0 mg/dl). W258X was only the risk in males with SUA of ≤ 3.0 mg/dl. CONCLUSION Our study accurately reveals the prevalence of RHUC and provides genetic evidence for its definition (SUA ≤ 2.0 mg/dl). We also show that individuals with SUA of ≤ 3.0 mg/dl, especially males, are prone to RHUC. Our findings will help to promote a better epidemiological understanding of RHUC as well as more accurate diagnosis, especially in males with mild hypouricemia.
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Affiliation(s)
- Akiyoshi Nakayama
- Department of Integrative Physiology and Bio-Nano Medicine, National Defense Medical College, Tokorozawa, Japan
| | - Yusuke Kawamura
- Department of Integrative Physiology and Bio-Nano Medicine, National Defense Medical College, Tokorozawa, Japan
| | - Yu Toyoda
- Department of Integrative Physiology and Bio-Nano Medicine, National Defense Medical College, Tokorozawa, Japan.,Department of Pharmacy, the University of Tokyo Hospital, Faculty of Medicine, the University of Tokyo, Tokyo, Japan
| | - Seiko Shimizu
- Department of Integrative Physiology and Bio-Nano Medicine, National Defense Medical College, Tokorozawa, Japan
| | - Makoto Kawaguchi
- Department of Integrative Physiology and Bio-Nano Medicine, National Defense Medical College, Tokorozawa, Japan
| | - Yuka Aoki
- Department of Integrative Physiology and Bio-Nano Medicine, National Defense Medical College, Tokorozawa, Japan
| | - Kenji Takeuchi
- Department of Preventive Medicine, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Rieko Okada
- Department of Preventive Medicine, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yoko Kubo
- Department of Preventive Medicine, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Toshihiko Imakiire
- Department of Nephrology and Endocrinology, National Defense Medical College, Tokorozawa, Japan
| | - Satoko Iwasawa
- Department of Preventive Medicine and Public Health, National Defense Medical College, Tokorozawa, Japan
| | - Hiroshi Nakashima
- Department of Preventive Medicine and Public Health, National Defense Medical College, Tokorozawa, Japan
| | - Masashi Tsunoda
- Department of Preventive Medicine and Public Health, National Defense Medical College, Tokorozawa, Japan
| | - Keiichi Ito
- Department of Urology, National Defense Medical College, Tokorozawa, Japan
| | - Hiroo Kumagai
- Department of Nephrology and Endocrinology, National Defense Medical College, Tokorozawa, Japan
| | - Tappei Takada
- Department of Pharmacy, the University of Tokyo Hospital, Faculty of Medicine, the University of Tokyo, Tokyo, Japan
| | - Kimiyoshi Ichida
- Department of Pathophysiology, Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan
| | - Nariyoshi Shinomiya
- Department of Integrative Physiology and Bio-Nano Medicine, National Defense Medical College, Tokorozawa, Japan
| | - Hirotaka Matsuo
- Department of Integrative Physiology and Bio-Nano Medicine, National Defense Medical College, Tokorozawa, Japan
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