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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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Zhou J, Zhang M, Xie Q, Xu N, Li M, Zhang M, Hao C. Recurrent exercise-induced acute kidney injury associated with hypouricemia: a case report and literature review. BMC Nephrol 2023; 24:384. [PMID: 38129773 PMCID: PMC10740252 DOI: 10.1186/s12882-023-03378-w] [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: 06/23/2022] [Accepted: 10/26/2023] [Indexed: 12/23/2023] Open
Abstract
BACKGROUND Hereditary renal hypouricemia (RHUC) is a heterogenous disorder characterized by defective uric acid (UA) reabsorption resulting in hypouricemia and increased fractional excretion of UA. RHUC is an important cause of exercise-induced acute kidney injury (EIAKI), nephrolithiasis and posterior reversible encephalopathy syndrome (PRES). We present here an unusual case of a patient with RHUC who presented with recurrent EIAKI and had two heterozygous mutations in the SLC2A9 gene. CASE PRESENTATION A 43-year old man was admitted to our clinic because of bilateral loin pain, nausea and sleeplessness for 3 days after strenuous exercise. The laboratory results revealed increased levels of blood urea nitrogen (BUN) (15 mmol/l) and serum creatinine (Scr) (450 μmol/l), while the UA level was extremely low at 0.54 mg/dl, and his fractional excretion of urate (FE-UA) was 108%. The patient had an episode of acute kidney injury after playing soccer approximately 20 years ago, and on routine physical examination, his UA was less than 0.50 mg/dl. In view of the marked hypouricemia and high FE-UA, a diagnosis of RHUC was suspected, which led us to perform mutational screening of the SLC22A12 and SLC2A9 genes. DNA sequencing revealed no mutation in SLC22A12 gene, but two heterozygous mutations in the SLC2A9 gene. CONCLUSIONS This is a rare report of a patient with RHUC2 due to the mutation of SLC2A9. And this unique symptom of EIAKI and decreased or normal serum concentrations of UA warrant more attention as an early cue of RHUC.
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Affiliation(s)
- Jie Zhou
- Division of Nephrology, Huashan Hospital, Fudan University, Shanghai, China
- Department of Nephrology, Shuguang Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Min Zhang
- Division of Nephrology, Huashan Hospital, Fudan University, Shanghai, China.
| | - Qionghong Xie
- Division of Nephrology, Huashan Hospital, Fudan University, Shanghai, China
| | - Ningxin Xu
- Division of Nephrology, Huashan Hospital, Fudan University, Shanghai, China
| | - Mingxin Li
- Division of Nephrology, Huashan Hospital, Fudan University, Shanghai, China
| | - Ming Zhang
- Division of Nephrology, Huashan Hospital, Fudan University, Shanghai, China
| | - Chuanming Hao
- Division of Nephrology, Huashan Hospital, Fudan University, Shanghai, China
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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, 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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Ye J, Zeng Z, Chen Y, Wu Z, Yang Q, Sun T. Examining an Association of Single Nucleotide Polymorphisms with Hyperuricemia in Chinese Flight Attendants. Pharmgenomics Pers Med 2022; 15:589-602. [PMID: 35702613 PMCID: PMC9188807 DOI: 10.2147/pgpm.s364206] [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: 02/28/2022] [Accepted: 05/23/2022] [Indexed: 11/23/2022] Open
Abstract
Background Both genetic and environmental factors strongly affect serum uric acid (SUA) concentrations. The incidence of hyperuricemia tends to be younger in the Chinese population. In particular, we have found a high prevalence of hyperuricemia among Chinese flight attendants, aged from 20 to 40, in our survey. This study aims to evaluate whether there is an association between gene polymorphisms and hyperuricemia among Chinese flight attendants. Methods A total of 532 flight attendants with high and normal serum uric acid levels were recruited. Allele-specific polymerase chain reaction (AS-PCR) was performed using blood samples of enrolled subjects. Results Previous studies have reported single nucleotide polymorphisms (SNPs) that are tightly associated with uric acid levels. Among them, six SNPs that are strongly associated with SUA or gout in Asians, for instance ABCG2 (rs2231142, rs72552713 and rs2231137), GCKR (rs780094), SLC2A9 (rs1014290) and SLC17A1 (rs1183201), were selected for AS-PCR analyses. We found that SNPs such as ABCG2 rs2231142, GCKR rs780094 and SLC2A9 rs1014290 are strongly associated with hyperuricemia in male flight attendants, and SLC2A9 rs1014290 among female flight attendants. Conclusion Our study provides evidences of an association between SNPs and hyperuricemia in the Chinese flight attendants, and highlights the significance of improving diagnostics and prevention of disease development in uric acid metabolism disorders and gout using these SNPs.
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Affiliation(s)
- Jianpin Ye
- Outpatient Department Laboratory, Xiamen Aviation, Xiamen, Fujian, People’s Republic of China
| | - Zhiwei Zeng
- Center for Precision Medicine, School of Medicine and School of Biomedical Sciences, Huaqiao University, Xiamen, Fujian, People’s Republic of China
| | - Yuxian Chen
- Taokang Institute of Neuro Medicine, Xiamen, Fujian, People’s Republic of China
| | - Zhenkun Wu
- Taokang Institute of Neuro Medicine, Xiamen, Fujian, People’s Republic of China
| | - Qingwei Yang
- Department of Neurology, Zhongshan Hospital, School of Medicine, Xiamen University, Xiamen, Fujian, People’s Republic of China
| | - Tao Sun
- Center for Precision Medicine, School of Medicine and School of Biomedical Sciences, Huaqiao University, Xiamen, Fujian, People’s Republic of China
- Correspondence: Tao Sun, Center for Precision Medicine, School of Medicine and School of Biomedical Sciences, Huaqiao University, Xiamen, Fujian, People’s Republic of China, Email
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Song S, Lou Y, Mao Y, Wen X, Fan M, He Z, Shen Y, Wen C, Shao T. Alteration of Gut Microbiome and Correlated Amino Acid Metabolism Contribute to Hyperuricemia and Th17-Driven Inflammation in Uox-KO Mice. Front Immunol 2022; 13:804306. [PMID: 35197978 PMCID: PMC8858814 DOI: 10.3389/fimmu.2022.804306] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 01/12/2022] [Indexed: 12/11/2022] Open
Abstract
Although gut dysbiosis had been demonstrated to be an important factor affecting hyperuricemia (HUA) and gout, little is known for its potential mechanistic connections. In this study, Uox-KO mice model that with spontaneously developed pronounced HUA and urate nephropathy was used to explore the pathophysiologic mechanism of microbiota alterations in HUA and gout with integrated multi-omics analysis. 16S rRNA gene sequencing was performed to characterize the characteristic bacteria, and untargeted LC/MS analysis was applied to reveal the featured metabolites. Our results showed there was a significant shift in gut microbiota composition and function in Uox-KO mice compared to WT mice and apparent metabolomics differences between the two groups. Among them, amino acids metabolism appears to play a critical role. Correlation analysis further revealed that the characteristic metabolites were strongly influenced by the discrepant bacterial genera. Furthermore, impairment of intestinal integrity and profound alterations in the profile of solute carrier family resulted in dysregulation of amino acids transportation, which subsequently impacted serum uric acid level and CD4+ Th17 driven inflammation. Together, these data indicate that gut dysbiosis promotes purine metabolism disorder and inflammation in Uox-KO mice. Remodeling the gut microbiota is a promising strategy to combat HUA and gout.
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Affiliation(s)
- Siyue Song
- College of Basic Medical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
| | - Yu Lou
- College of Basic Medical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
| | - Yingying Mao
- School of Public Health, Zhejiang Chinese Medical University, Hangzhou, China
| | - Xianghui Wen
- College of Basic Medical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
| | - Moqi Fan
- College of Basic Medical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
| | - Zhixing He
- College of Basic Medical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
| | - Yang Shen
- The Second Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou, China
| | - Chengping Wen
- College of Basic Medical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
- *Correspondence: Chengping Wen, ; Tiejuan Shao,
| | - Tiejuan Shao
- College of Basic Medical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
- *Correspondence: Chengping Wen, ; Tiejuan Shao,
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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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Identification of two novel heterozygous SLC2A9 mutations in a Chinese woman and review of literature. Clin Chim Acta 2021; 523:58-64. [PMID: 34499869 DOI: 10.1016/j.cca.2021.09.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 07/20/2021] [Accepted: 09/03/2021] [Indexed: 11/23/2022]
Abstract
OBJECTIVE This study is aimed to describe the clinical and genetic characteristics of a Chinese woman diagnosed with renal hypouricemia type 2 (RHUC2). We also summarize the advances in research on RHUC2 by reviewing related literature. METHODS We measured clinical parameters of a 57-year-old female and performed whole-exome sequencing to screen for mutations. Human embryonic kidney 293 cells were transiently transfected with plasmids containing wild-type or mutants. Relative mRNA quantification was determined by real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR). RESULTS This patient was diagnosed with diabetes and coronary heart disease. In addition, a decrease in 24-hour urinary chloride was observed. Two novel heterozygous variants of SLC2A9 (NM_020041.2): c.682-2_682-1insC and c.267C > G (p.Y89X) were identified. The mini-gene splicing assay revealed that c.682-2_682-1insC variant resulted in a frameshift mutation p. E228PfsX23. There was a statistically significant difference in mRNA expression level between the two mutants and the wild-type. CONCLUSIONS These findings strongly suggest that the two novel mutations are the causative agents of RHUC2. In particular, our findings provide further insights into the function of SLC2A9 and mechanisms of the complications.
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Identification of Two Dysfunctional Variants in the ABCG2 Urate Transporter Associated with Pediatric-Onset of Familial Hyperuricemia and Early-Onset Gout. Int J Mol Sci 2021; 22:ijms22041935. [PMID: 33669292 PMCID: PMC7920026 DOI: 10.3390/ijms22041935] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 02/03/2021] [Accepted: 02/10/2021] [Indexed: 12/15/2022] Open
Abstract
The ABCG2 gene is a well-established hyperuricemia/gout risk locus encoding a urate transporter that plays a crucial role in renal and intestinal urate excretion. Hitherto, p.Q141K—a common variant of ABCG2 exhibiting approximately one half the cellular function compared to the wild-type—has been reportedly associated with early-onset gout in some populations. However, compared with adult-onset gout, little clinical information is available regarding the association of other uricemia-associated genetic variations with early-onset gout; the latent involvement of ABCG2 in the development of this disease requires further evidence. We describe a representative case of familial pediatric-onset hyperuricemia and early-onset gout associated with a dysfunctional ABCG2, i.e., a clinical history of three generations of one Czech family with biochemical and molecular genetic findings. Hyperuricemia was defined as serum uric acid (SUA) concentrations 420 μmol/L for men or 360 μmol/L for women and children under 15 years on two measurements, performed at least four weeks apart. The proband was a 12-year-old girl of Roma ethnicity, whose SUA concentrations were 397–405 µmol/L. Sequencing analyses focusing on the coding region of ABCG2 identified two rare mutations—c.393G>T (p.M131I) and c.706C>T (p.R236X). Segregation analysis revealed a plausible link between these mutations and hyperuricemia and the gout phenotype in family relatives. Functional studies revealed that p.M131I and p.R236X were functionally deficient and null, respectively. Our findings illustrate why genetic factors affecting ABCG2 function should be routinely considered in clinical practice as part of a hyperuricemia/gout diagnosis, especially in pediatric-onset patients with a strong family history.
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Teng L, Zhang Y, Ye L, Lv J, Mao Y, Schneider R, Chen J, Jiang H, Wu J. Donor-derived hypouricemia in irrelevant recipients caused by kidney transplantation. ANNALS OF TRANSLATIONAL MEDICINE 2020; 8:330. [PMID: 32355774 PMCID: PMC7186701 DOI: 10.21037/atm.2020.02.140] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Background Hereditary renal hypouricemia (HRH) is a genetically heterogenetic disease. Patients with HRH are almost asymptomatic; but some may experience exercise-induced acute kidney injury (EAKI) and nephrolithiasis which may bring concerns regarding the risk-benefit ratio as marginal kidney donors. This study examined the pathogenic mutations of hypouricemia in two recipients after receiving kidney transplantation, providing preliminary evidence for the mechanism of hypouricemia. Methods Two participants underwent detailed biochemical examinations. DNA and RNA were extracted from transplant specimens for sequencing. The whole-genome sequencing and polymerase chain reaction (PCR) amplification were performed to confirm the pathogenic genes. Functional effects of mutant proteins were verified by bioinformatics analysis. RNA-sequencing (RNA-seq) was used to study the transcriptome of hypouricemia. Results Both of the recipients had the low serum uric acid (UA) (45–65 µmol/l), high fraction excretion of UA (44% and 75%) and an increase in the UA clearance (35.9 and 73.3 mL/min) with a functioning graft. The sequencing analyses revealed 7 kinds of potential mutational genes in this case, two novel mutations p.R89H and p.L181V in SLC22A12 gene which were revealed by bioinformatics could be pathogenic in nature. Conclusions Two novel mutations of SLC22A12 were identified. Preliminary functional analysis revealed a potential deleterious effect of these mutations in the grafts derived from the donor and sequencing analysis expand the molecular mechanisms of renal hypouricemia.
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Affiliation(s)
- Lisha Teng
- Department of the Kidney Disease Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310003, China.,Key Laboratory of Kidney Disease Prevention and Control Technology, Hangzhou 310003, China.,The Third-Grade Laboratory under the National State, Administration of Traditional Chinese Medicine, Hangzhou 310000, China
| | - Yanling Zhang
- Department of the Kidney Disease Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310003, China.,Key Laboratory of Kidney Disease Prevention and Control Technology, Hangzhou 310003, China.,The Third-Grade Laboratory under the National State, Administration of Traditional Chinese Medicine, Hangzhou 310000, China.,Department of Nephrology, The Second Hospital of Shaoxing, Shaoxing 312000, China
| | - Luxi Ye
- Department of the Kidney Disease Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310003, China.,Key Laboratory of Kidney Disease Prevention and Control Technology, Hangzhou 310003, China.,The Third-Grade Laboratory under the National State, Administration of Traditional Chinese Medicine, Hangzhou 310000, China
| | - Junhao Lv
- Department of the Kidney Disease Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310003, China.,Key Laboratory of Kidney Disease Prevention and Control Technology, Hangzhou 310003, China.,The Third-Grade Laboratory under the National State, Administration of Traditional Chinese Medicine, Hangzhou 310000, China
| | - Youying Mao
- Nephrology Department, Shanghai Children's Medical Center, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Ronen Schneider
- Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Jianghua Chen
- Department of the Kidney Disease Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310003, China.,Key Laboratory of Kidney Disease Prevention and Control Technology, Hangzhou 310003, China.,The Third-Grade Laboratory under the National State, Administration of Traditional Chinese Medicine, Hangzhou 310000, China
| | - Hong Jiang
- Department of the Kidney Disease Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310003, China.,Key Laboratory of Kidney Disease Prevention and Control Technology, Hangzhou 310003, China.,The Third-Grade Laboratory under the National State, Administration of Traditional Chinese Medicine, Hangzhou 310000, China
| | - Jianyong Wu
- Department of the Kidney Disease Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310003, China.,Key Laboratory of Kidney Disease Prevention and Control Technology, Hangzhou 310003, China.,The Third-Grade Laboratory under the National State, Administration of Traditional Chinese Medicine, Hangzhou 310000, China
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Shamekhi Amiri F, Rostami Z. Prevalence of inherited changes of uric acid levels in kidney dysfunction including stage 5 D and T: a systematic review. RENAL REPLACEMENT THERAPY 2020. [DOI: 10.1186/s41100-020-0258-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background/aims
Familial juvenile hereditary nephropathy (FJHN) is characterized by hyperuricemia due to severely impaired urinary excretion of urate. Hereditary renal hypouricemia is an inborn error of membrane transport. Because studies of inherited tubulopathy is rare, prevalence and diagnosis of these inherited tubulopathy increase with genetic testing.The aim of this study is to investigate prevalence of clinical features, biochemical profiles, and genetic analysis of patients with changes in serum uric acid levels in inherited tubulopathy.
Main body
The paper has written based on searching PubMed and Google Scholar to identify potentially relevant articles or abstracts. In this retrospective study, a total 65 patients with changes of serum uric acid levels and kidney dysfunction were investigated. Clinical features, laboratory data at initial presentation, management, and outcomes were collected. Forty studies (65 participants) included in this review. The mean ± SD of age of study patients in inherited tubulointerstitial kidney disease was 25.29 ± 14.69 years. Mean ± SD age of patients at time of diagnosis in inherited renal hypouricemia was 18.83 ± 10.59 years. Correlation between exon region in mutated UMOD, SLC22A12, and SLC2A9 genes and serum uric acid levels were assessed and revealed significant statistical correlation between exon region of SLC2A9 mutation and serum uric acid levels. Prevalence of progression to end-stage kidney disease in patients with inherited tubulointerstitial kidney disease and inherited renal hypouricemia were assessed 20% and 2.5%, respectively. There was nephrolithiasis in two patients (2/25, 8%) with inherited renal hypouricemia.
Conclusions
This study shows that UMOD and SLC22A12 gene mutations were responsible for majority of autosomal-dominant tubulointerstitial kidney disease and inherited renal hypouricemia, respectively.
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Furuto Y, Kawamura M, Namikawa A, Takahashi H, Shibuya Y, Mori T, Sohara E. Non-urate transporter 1, non-glucose transporter member 9-related renal hypouricemia and acute renal failure accompanied by hyperbilirubinemia after anaerobic exercise: a case report. BMC Nephrol 2019; 20:433. [PMID: 31771519 PMCID: PMC6878684 DOI: 10.1186/s12882-019-1618-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2019] [Accepted: 11/08/2019] [Indexed: 11/11/2022] Open
Abstract
Background Renal hypouricemia (RHUC) is an inherited heterogenous disorder caused by faulty urate reabsorption transporters in the renal proximal tubular cells. Anaerobic exercise may induce acute kidney injury in individuals with RHUC that is not caused by exertional rhabdomyolysis; it is called acute renal failure with severe loin pain and patchy renal ischemia after anaerobic exercise (ALPE). RHUC is the most important risk factor for ALPE. However, the mechanism of onset of ALPE in patients with RHUC has not been elucidated. The currently known genes responsible for RHUC are SLC22A12 and SLC2A9. Case presentation A 37-year-old man presented with loin pain after exercising. Despite having a healthy constitution from birth, biochemical examination revealed hypouricemia, with a uric acid (UA) level of < 1 mg/dL consistently at every health check. We detected acute kidney injury, with a creatinine (Cr) level of 4.1 mg/dL, and elevated bilirubin; hence, the patient was hospitalized. Computed tomography revealed no renal calculi, but bilateral renal swelling was noted. Magnetic resonance imaging detected cuneiform lesions, indicating bilateral renal ischemia. Fractional excretion values of sodium and UA were 0.61 and 50.5%, respectively. Urinary microscopy showed lack of tubular injury. The patient’s older sister had hypouricemia. The patient was diagnosed with ALPE. Treatment with bed rest, fluid replacement, and nutrition therapy improved renal function and bilirubin levels, and the patient was discharged on day 5. Approximately 1 month after onset of ALPE, his Cr, UA, and TB levels were 0.98, 0.8, and 0.9 mg/dL, respectively. We suspected familial RHUC due to the hypouricemia and family history and performed genetic testing but did not find the typical genes responsible for RHUC. A full genetic analysis was opposed by the family. Conclusions To the best of our knowledge, this is the first report of ALPE with hyperbilirubinemia. Bilirubin levels may become elevated as a result of heme oxygenase-1 activation, occurring in exercise-induced acute kidney injury in patients with RHUC; this phenomenon suggests renal ischemia-reperfusion injury. A new causative gene coding for a urate transporter may exist, and its identification would be useful to clarify the urate transport mechanism.
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Affiliation(s)
- Yoshitaka Furuto
- Department of Hypertension and Nephrology, NTT Medical Centre, Tokyo, 5-9-22, Higasi-Gotanda, Shinagawa-ku, Tokyo, 141-8625, Japan.
| | - Mariko Kawamura
- Department of Hypertension and Nephrology, NTT Medical Centre, Tokyo, 5-9-22, Higasi-Gotanda, Shinagawa-ku, Tokyo, 141-8625, Japan
| | - Akio Namikawa
- Department of Hypertension and Nephrology, NTT Medical Centre, Tokyo, 5-9-22, Higasi-Gotanda, Shinagawa-ku, Tokyo, 141-8625, Japan
| | - Hiroko Takahashi
- Department of Hypertension and Nephrology, NTT Medical Centre, Tokyo, 5-9-22, Higasi-Gotanda, Shinagawa-ku, Tokyo, 141-8625, Japan
| | - Yuko Shibuya
- Department of Hypertension and Nephrology, NTT Medical Centre, Tokyo, 5-9-22, Higasi-Gotanda, Shinagawa-ku, Tokyo, 141-8625, Japan
| | - Takayasu Mori
- Department of Nephrology, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo, 113-8519, Japan
| | - Eisei Sohara
- Department of Nephrology, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo, 113-8519, Japan
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Hypouricemia: what the practicing rheumatologist should know about this condition. Clin Rheumatol 2019; 39:135-147. [PMID: 31650389 DOI: 10.1007/s10067-019-04788-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 08/27/2019] [Accepted: 09/21/2019] [Indexed: 12/15/2022]
Abstract
We presented an update in the field of hypouricemia, which is defined as a serum urate concentration of < 2 mg/dL (119 μmol/L), for the practicing rheumatologist, who usually is the consulting physician in cases of disorders of urate metabolism. We performed a narrative review through a literature search for original and review articles in the field of human hypouricemia published between January 1950 and July 2018. We divided the etiology of hypouricemia into two main categories: those associated with a decrease in urate production and those promoting the elimination of urate via the kidneys. The most common conditions associated with these categories are discussed. Furthermore, the etiology of hypouricemia may be associated with certain medications prescribed by the practicing rheumatologists, such as the following: urate-lowering drugs (allopurinol and febuxostat); recombinant uricase (pegloticase); uricosuric agents (probenecid, benzbromarone); urate transporter URAT1 inhibitor (lesinurad); angiotensin II receptor blocker (losartan); fenofibrate; high-dose trimethoprim-sulfamethoxazole; some NSAID; and high-dose salicylate therapy. The rheumatologist is considered an expert in the metabolism of urate and its associated pathological conditions. Therefore, specialists must recognize hypouricemia as a biomarker of various pathological and potentially harmful conditions, highlighting the importance of conducting a deeper clinical investigation to reach a more accurate diagnosis and treatment.
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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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15
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Clinical and Functional Characterization of a Novel URAT1 Dysfunctional Variant in a Pediatric Patient with Renal Hypouricemia. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9173479] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Renal hypouricemia (RHUC) is caused by an inherited defect in the main (reabsorptive) renal urate transporters, URAT1 and GLUT9. RHUC is characterized by decreased concentrations of serum uric acid and an increase in its excretion fraction. Patients suffer from hypouricemia, hyperuricosuria, urolithiasis, and even acute kidney injury. We report the clinical, biochemical, and genetic findings of a pediatric patient with hypouricemia. Sequencing analysis of the coding region of SLC22A12 and SLC2A9 and a functional study of a novel RHUC1 variant in the Xenopus expression system were performed. The proband showed persistent hypouricemia (67–70 µmol/L; ref. range 120–360 µmol/L) and hyperuricosuria (24–34%; ref. range 7.3 ± 1.3%). The sequencing analysis identified common non-synonymous allelic variants c.73G > A, c.844G > A, c.1049C > T in the SLC2A9 gene and rare variants c.973C > T, c.1300C > T in the SLC22A12 gene. Functional characterization of the novel RHUC associated c.973C > T (p. R325W) variant showed significantly decreased urate uptake, an irregular URAT1 signal on the plasma membrane, and reduced cytoplasmic staining. RHUC is an underdiagnosed disorder and unexplained hypouricemia warrants detailed metabolic and genetic investigations. A greater awareness of URAT1 and GLUT9 deficiency by primary care physicians, nephrologists, and urologists is crucial for identifying the disorder.
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Zhou Z, Wang K, Zhou J, Wang C, Li X, Cui L, Han L, Liu Z, Ren W, Wang X, Zhang K, Li Z, Pan D, Li C, Shi Y. Amplicon targeted resequencing for SLC2A9 and SLC22A12 identified novel mutations in hypouricemia subjects. Mol Genet Genomic Med 2019; 7:e00722. [PMID: 31131560 PMCID: PMC6625124 DOI: 10.1002/mgg3.722] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 02/19/2019] [Accepted: 04/15/2019] [Indexed: 01/05/2023] Open
Abstract
Background To identify potential causative mutations in SLC2A9 and SLC22A12 that lead to hypouricemia or hyperuricemia (HUA). Methods Targeted resequencing of whole exon regions of SLC2A9 and SLC22A12 was performed in three cohorts of 31 hypouricemia, 288 HUA and 280 normal controls. Results A total of 84 high‐quality variants were identified in these three cohorts. Eighteen variants were nonsynonymous or in splicing region, and then included in the following association analysis. For common variants, no significant effects on hypouricemia or HUA were identified. For rare variants, six single nucleotide variations (SNVs) p.T21I and p.G13D in SLC2A9, p.W50fs, p.Q382L, p.V547L and p.E458K in SLC22A12, occurred in totally six hypouricemia subjects and were absent in HUA and normal controls. Allelic and genotypic frequency distributions of the six SNVs differed significantly between the hypouricemia and normal controls even after multiple testing correction, and p.G13D in SLC2A9 and p.V547L in SLC22A12 were newly reported. All these mutations had no significant effects on HUA susceptibility, while the gene‐based analyses substantiated the significant results on hypouricemia. Conclusion Our study first presents a comprehensive mutation spectrum of hypouricemia in a large Chinese cohort.
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Affiliation(s)
- Zhaowei Zhou
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiaric Disorders (Ministry of Education), Shanghai Jiao Tong University, Shanghai, P.R. China
| | - Ke Wang
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiaric Disorders (Ministry of Education), Shanghai Jiao Tong University, Shanghai, P.R. China
| | - Juan Zhou
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiaric Disorders (Ministry of Education), Shanghai Jiao Tong University, Shanghai, P.R. China
| | - Can Wang
- Qingdao Key Laboratory of Gout, The Affiliated Hospital of Qingdao University, Qingdao, P.R. China.,Shandong Provincial Key Laboratory of Metabolic Disease, The Affiliated Hospital of Qingdao University, Qingdao, P.R. China.,Metabolic Disease Institute, Qingdao University, Qingdao, P.R. China
| | - Xinde Li
- Qingdao Key Laboratory of Gout, The Affiliated Hospital of Qingdao University, Qingdao, P.R. China.,Shandong Provincial Key Laboratory of Metabolic Disease, The Affiliated Hospital of Qingdao University, Qingdao, P.R. China.,Metabolic Disease Institute, Qingdao University, Qingdao, P.R. China
| | - Lingling Cui
- Qingdao Key Laboratory of Gout, The Affiliated Hospital of Qingdao University, Qingdao, P.R. China.,Shandong Provincial Key Laboratory of Metabolic Disease, The Affiliated Hospital of Qingdao University, Qingdao, P.R. China.,Metabolic Disease Institute, Qingdao University, Qingdao, P.R. China
| | - Lin Han
- Qingdao Key Laboratory of Gout, The Affiliated Hospital of Qingdao University, Qingdao, P.R. China.,Shandong Provincial Key Laboratory of Metabolic Disease, The Affiliated Hospital of Qingdao University, Qingdao, P.R. China.,Metabolic Disease Institute, Qingdao University, Qingdao, P.R. China
| | - Zhen Liu
- Qingdao Key Laboratory of Gout, The Affiliated Hospital of Qingdao University, Qingdao, P.R. China.,Shandong Provincial Key Laboratory of Metabolic Disease, The Affiliated Hospital of Qingdao University, Qingdao, P.R. China.,Metabolic Disease Institute, Qingdao University, Qingdao, P.R. China
| | - Wei Ren
- Qingdao Key Laboratory of Gout, The Affiliated Hospital of Qingdao University, Qingdao, P.R. China.,Shandong Provincial Key Laboratory of Metabolic Disease, The Affiliated Hospital of Qingdao University, Qingdao, P.R. China.,Metabolic Disease Institute, Qingdao University, Qingdao, P.R. China
| | - Xuefeng Wang
- Qingdao Key Laboratory of Gout, The Affiliated Hospital of Qingdao University, Qingdao, P.R. China.,Shandong Provincial Key Laboratory of Metabolic Disease, The Affiliated Hospital of Qingdao University, Qingdao, P.R. China.,Metabolic Disease Institute, Qingdao University, Qingdao, P.R. China
| | - Keke Zhang
- Qingdao Key Laboratory of Gout, The Affiliated Hospital of Qingdao University, Qingdao, P.R. China.,Shandong Provincial Key Laboratory of Metabolic Disease, The Affiliated Hospital of Qingdao University, Qingdao, P.R. China.,Metabolic Disease Institute, Qingdao University, Qingdao, P.R. China.,The Department of Endocrinology and Metabolism, The Affiliated Hospital of Qingdao University, Qingdao, P.R. China
| | - Zhiqiang Li
- Biomedical Sciences Institute, the Qingdao Branch of SJTU Bio-X Institutes, Qingdao University, Qingdao, P.R. China
| | - Dun Pan
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiaric Disorders (Ministry of Education), Shanghai Jiao Tong University, Shanghai, P.R. China
| | - Changgui Li
- Qingdao Key Laboratory of Gout, The Affiliated Hospital of Qingdao University, Qingdao, P.R. China.,Shandong Provincial Key Laboratory of Metabolic Disease, The Affiliated Hospital of Qingdao University, Qingdao, P.R. China.,Metabolic Disease Institute, Qingdao University, Qingdao, P.R. China.,The Department of Endocrinology and Metabolism, The Affiliated Hospital of Qingdao University, Qingdao, P.R. China
| | - Yongyong Shi
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiaric Disorders (Ministry of Education), Shanghai Jiao Tong University, Shanghai, P.R. China.,Qingdao Key Laboratory of Gout, The Affiliated Hospital of Qingdao University, Qingdao, P.R. China.,Shandong Provincial Key Laboratory of Metabolic Disease, The Affiliated Hospital of Qingdao University, Qingdao, P.R. China.,Biomedical Sciences Institute, the Qingdao Branch of SJTU Bio-X Institutes, Qingdao University, Qingdao, P.R. China
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Furuhashi M, Mori K, Tanaka M, Maeda T, Matsumoto M, Murase T, Nakamura T, Koyama M, Moniwa N, Ohnishi H, Saitoh S, Shimamoto K, Miura T. Unexpected high plasma xanthine oxidoreductase activity in female subjects with low levels of uric acid. Endocr J 2018; 65:1083-1092. [PMID: 30068899 DOI: 10.1507/endocrj.ej18-0127] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Hypouricemia is a high-risk factor of exercise-induced acute kidney injury (EIAKI) probably through a lack of an antioxidant effect of uric acid. Xanthine oxidoreductase (XOR) is an enzyme that catalyzes the formation of uric acid from hypoxanthine and xanthine, leading to an increase in superoxide and reactive oxygen species. Activation of XOR has been proposed to promote oxidative stress-related tissue injury. We measured plasma XOR activity by a sensitive and accurate assay using a combination of liquid chromatography and triple quadrupole mass spectrometry in subjects with relatively low levels of uric acid (≤4.0 mg/dL) who were recruited from 627 subjects (male/female: 292/335) in the Tanno-Sobetsu Study, a population-based cohort. The numbers of subjects with uric acid ≤4.0 mg/dL, ≤3.0 mg/dL and ≤2.0 mg/dL were 72 (11.5%, male/female: 5/67), 13 (2.1%, all females) and 2 (0.3%, both females), respectively. Plasma XOR activities in 5 male subjects were below the median value of the 292 male subjects. In 12 (17.9%) of the 67 female subjects with uric acid ≤4.0 mg/dL, plasma XOR activities were above the upper quartile value of the 335 female subjects. Eleven of the 12 female subjects with high plasma XOR activity and a low uric acid level had liver dysfunction and/or insulin resistance. In conclusion, unexpected high plasma XOR activities were found in some female subjects with relatively low levels of uric acid. Measurement of plasma XOR activity may help to identify hypouricemic patients with a high risk for EIAKI.
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Affiliation(s)
- Masato Furuhashi
- Department of Cardiovascular, Renal and Metabolic Medicine, Sapporo Medical University School of Medicine, Sapporo 060-8543, Japan
| | - Kazuma Mori
- Department of Cardiovascular, Renal and Metabolic Medicine, Sapporo Medical University School of Medicine, Sapporo 060-8543, Japan
| | - Marenao Tanaka
- Department of Cardiovascular, Renal and Metabolic Medicine, Sapporo Medical University School of Medicine, Sapporo 060-8543, Japan
| | - Takuto Maeda
- Department of Nephrology, Teine Keijinkai Hospital, Sapporo 006-8555, Japan
| | - Megumi Matsumoto
- Department of Cardiovascular, Renal and Metabolic Medicine, Sapporo Medical University School of Medicine, Sapporo 060-8543, Japan
| | - Takayo Murase
- Sanwa Kagaku Kenkyusho Co., Ltd., Inabe 511-0406, Japan
| | | | - Masayuki Koyama
- Department of Cardiovascular, Renal and Metabolic Medicine, Sapporo Medical University School of Medicine, Sapporo 060-8543, Japan
- Department of Public Health, Sapporo Medical University School of Medicine, Sapporo 060-8543, Japan
| | - Norihito Moniwa
- Department of Cardiovascular, Renal and Metabolic Medicine, Sapporo Medical University School of Medicine, Sapporo 060-8543, Japan
| | - Hirofumi Ohnishi
- Department of Cardiovascular, Renal and Metabolic Medicine, Sapporo Medical University School of Medicine, Sapporo 060-8543, Japan
- Department of Public Health, Sapporo Medical University School of Medicine, Sapporo 060-8543, Japan
| | - Shigeyuki Saitoh
- Department of Cardiovascular, Renal and Metabolic Medicine, Sapporo Medical University School of Medicine, Sapporo 060-8543, Japan
- Department of Nursing, Division of Medical and Behavioral Subjects, Sapporo Medical University School of Health Sciences, Sapporo 060-8543, Japan
| | | | - Tetsuji Miura
- Department of Cardiovascular, Renal and Metabolic Medicine, Sapporo Medical University School of Medicine, Sapporo 060-8543, Japan
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Zhu W, Deng Y, Zhou X. Multiple Membrane Transporters and Some Immune Regulatory Genes are Major Genetic Factors to Gout. Open Rheumatol J 2018; 12:94-113. [PMID: 30123371 PMCID: PMC6062909 DOI: 10.2174/1874312901812010094] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Revised: 05/30/2018] [Accepted: 06/20/2018] [Indexed: 01/10/2023] Open
Abstract
Gout is a common form of inflammatory arthritis caused by hyperuricemia and the deposition of Monosodium Urate (MSU) crystals. It is also considered as a complex disorder in which multiple genetic factors have been identified in association with its susceptibility and/or clinical outcomes. Major genes that were associated with gout include URAT1, GLUT9, OAT4, NPT1 (SLC17A1), NPT4 (SLC17A3), NPT5 (SLC17A4), MCT9, ABCG2, ABCC4, KCNQ1, PDZK1, NIPAL1, IL1β, IL-8, IL-12B, IL-23R, TNFA, MCP-1/CCL2, NLRP3, PPARGC1B, TLR4, CD14, CARD8, P2X7R, EGF, A1CF, HNF4G and TRIM46, LRP2, GKRP, ADRB3, ADH1B, ALDH2, COMT, MAOA, PRKG2, WDR1, ALPK1, CARMIL (LRRC16A), RFX3, BCAS3, CNIH-2, FAM35A and MYL2-CUX2. The proteins encoded by these genes mainly function in urate transport, inflammation, innate immunity and metabolism. Understanding the functions of gout-associated genes will provide important insights into future studies to explore the pathogenesis of gout, as well as to develop targeted therapies for gout.
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Affiliation(s)
- Weifeng Zhu
- Department of Biochemistry and Molecular Biology, College of Basic Medical Sciences, Nanchang University, Nanchang, China.,Department of Internal Medicine, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Yan Deng
- Department of Internal Medicine, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, USA.,Department of Ophthalmology of Children, The Second Affiliated Hospital of Nanchang University, Nanchang, China
| | - Xiaodong Zhou
- Department of Internal Medicine, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, USA
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Vidanapathirana DM, Jayasena S, Jasinge E, Stiburkova B. A heterozygous variant in the SLC22A12 gene in a Sri Lanka family associated with mild renal hypouricemia. BMC Pediatr 2018; 18:210. [PMID: 29958533 PMCID: PMC6025733 DOI: 10.1186/s12887-018-1185-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 06/21/2018] [Indexed: 11/25/2022] Open
Abstract
Background Renal hypouricemia is a rare heterogeneous inherited disorder characterized by impaired tubular uric acid transport, reabsorption insufficiency and /or acceleration of secretion. The affected individuals are predisposed to nephrolithiasis and recurrent episodes of exercise-induced acute kidney injury. Type 1 is caused by dysfunctional variants in the SLC22A12 gene (URAT1), while type 2 is caused by defects in the SLC2A9 gene (GLUT9). To date, more than 150 patients with the loss-of-function mutations for the SLC22A12 gene have been found (compound heterozygotes and/or homozygotes), most of whom are Japanese and Koreans. Case presentation Herein, we report a nine year old Sri Lankan boy with renal hypouricemia (serum uric acid 97 μmol/L, fractional excretion of uric acid 33%).The sequencing analysis of SLC22A12 revealed a potentially deleterious missense variant c.1400C > T (p.T467 M, rs200104135) in heterozygous state. This variant has been previously identified in homozygous and/or compound heterozygous state with other causative SLC22A12 variant c.1245_1253del (p.L415_G417del) in Roma population. Conclusions This is the first identification of a family with mild renal hypouricemia1 associated to the p.T467 M variant. Detailed investigations of urate blood and urine concentrations in patients with unexplained hypouricemia are needed and renal hypouricemia should also be considered in patients other than those from Japan and/or Korea. Our finding confirms an uneven geographical and ethnic distribution of Romany prevalent SLC22A12 variant that need to be considered in Asian patients (population data Genome Aggregation Database: allele frequency in South Asia 0.007055, in East Asia 0.001330).
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Affiliation(s)
| | - Subashinie Jayasena
- Department of Chemical Pathology, Lady Ridgeway Hospital, Colombo, Sri Lanka
| | - Eresha Jasinge
- Department of Chemical Pathology, Lady Ridgeway Hospital, Colombo, Sri Lanka
| | - Blanka Stiburkova
- Institute of Rheumatology, Prague, Czech Republic.,Department of Paediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
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Abstract
Genome-wide association studies (GWAS) have identified nearly 30 loci associated with urate concentrations that also influence the subsequent risk of gout. The ABCG2 Q141 K variant is highly likely to be causal and results in internalization of ABCG2, which can be rescued by drugs. Three other GWAS loci contain uric acid transporter genes, which are also highly likely to be causal. However identification of causal genes at other urate loci is challenging. Finally, relatively little is known about the genetic control of progression from hyperuricemia to gout. Only 4 small GWAS have been published for gout.
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Affiliation(s)
- Tony Merriman
- Department of Biochemistry, University of Otago, 710 Cumberland Street, Dunedin 9054, New Zealand.
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21
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The Single Nucleotide Polymorphism rs1014290 of the SLC2A9 Gene Is Associated with Uric Acid Metabolism in Parkinson's Disease. PARKINSONS DISEASE 2017; 2017:7184927. [PMID: 29158942 PMCID: PMC5660784 DOI: 10.1155/2017/7184927] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 08/14/2017] [Accepted: 08/22/2017] [Indexed: 11/18/2022]
Abstract
Individuals with Parkinson's disease (PD) have lower uric acid levels than those without PD, and the CC genotype and C minor allele of a single nucleotide polymorphism (SNP), rs1014290 of SLC2A9, are associated with lower uric acid levels. We investigated the association of rs1014290 with uric acid metabolism in a cohort of PD cases (220) and controls (110) in a Han Chinese population. Uric acid levels were determined and rs1014290 was assayed using a mutation-sensitive on/off switch technology. PD uric acid levels (291.65 ± 76.29 μmol/L) were significantly lower than the controls (325.73 ± 74.23 μmol/L, P < 0.001, t-test). Individuals with rs1014290 TT and CT genotypes had higher uric acid levels, and those with the CC genotype had the lowest uric acid levels among both control and PD cases. The CC genotype and the C minor allele were statistically more frequent in the PD group compared to the control group. Those with the CC genotype had a statistically significant higher risk of PD than those with the TT or TC genotype (odds ratio [OR] = 2.249, 95% confidence interval [CI]: 1.129–4.480, and P = 0.021). Thus, SLC2A9 rs1014290 is related to lower uric acid levels in PD patients and can be a risk factor for PD in the Han population.
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Paganoni S, Nicholson K, Chan J, Shui A, Schoenfeld D, Sherman A, Berry J, Cudkowicz M, Atassi N. Urate levels predict survival in amyotrophic lateral sclerosis: Analysis of the expanded Pooled Resource Open-Access ALS clinical trials database. Muscle Nerve 2017; 57:430-434. [PMID: 28857199 DOI: 10.1002/mus.25950] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/27/2017] [Indexed: 12/12/2022]
Abstract
INTRODUCTION Urate has been identified as a predictor of amyotrophic lateral sclerosis (ALS) survival in some but not all studies. Here we leverage the recent expansion of the Pooled Resource Open-Access ALS Clinical Trials (PRO-ACT) database to study the association between urate levels and ALS survival. METHODS Pooled data of 1,736 ALS participants from the PRO-ACT database were analyzed. Cox proportional hazards regression models were used to evaluate associations between urate levels at trial entry and survival. RESULTS After adjustment for potential confounders (i.e., creatinine and body mass index), there was an 11% reduction in risk of reaching a survival endpoint during the study with each 1-mg/dL increase in uric acid levels (adjusted hazard ratio 0.89, 95% confidence interval 0.82-0.97, P < 0.01). DISCUSSION Our pooled analysis provides further support for urate as a prognostic factor for survival in ALS and confirms the utility of the PRO-ACT database as a powerful resource for ALS epidemiological research. Muscle Nerve 57: 430-434, 2018.
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Affiliation(s)
- Sabrina Paganoni
- Department of Neurology, Neurological Clinical Research Institute, Massachusetts General Hospital, Harvard Medical School, 165 Cambridge St, Suite 600 Boston, Massachusetts, 02114.,Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital, Boston, Massachusetts.,VA Boston Healthcare System, Boston, Massachusetts
| | - Katharine Nicholson
- Department of Neurology, Neurological Clinical Research Institute, Massachusetts General Hospital, Harvard Medical School, 165 Cambridge St, Suite 600 Boston, Massachusetts, 02114
| | - James Chan
- Massachusetts General Hospital Biostatistics Center, Boston, Massachusetts
| | - Amy Shui
- Massachusetts General Hospital Biostatistics Center, Boston, Massachusetts
| | - David Schoenfeld
- Massachusetts General Hospital Biostatistics Center, Boston, Massachusetts
| | - Alexander Sherman
- Department of Neurology, Neurological Clinical Research Institute, Massachusetts General Hospital, Harvard Medical School, 165 Cambridge St, Suite 600 Boston, Massachusetts, 02114
| | - James Berry
- Department of Neurology, Neurological Clinical Research Institute, Massachusetts General Hospital, Harvard Medical School, 165 Cambridge St, Suite 600 Boston, Massachusetts, 02114
| | - Merit Cudkowicz
- Department of Neurology, Neurological Clinical Research Institute, Massachusetts General Hospital, Harvard Medical School, 165 Cambridge St, Suite 600 Boston, Massachusetts, 02114
| | - Nazem Atassi
- Department of Neurology, Neurological Clinical Research Institute, Massachusetts General Hospital, Harvard Medical School, 165 Cambridge St, Suite 600 Boston, Massachusetts, 02114
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Dalbeth N, Stamp LK, Merriman TR. The genetics of gout: towards personalised medicine? BMC Med 2017; 15:108. [PMID: 28566086 PMCID: PMC5452604 DOI: 10.1186/s12916-017-0878-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 05/16/2017] [Indexed: 12/18/2022] Open
Abstract
Over the last decade, there have been major advances in the understanding of the genetic basis of hyperuricaemia and gout as well as of the pharmacogenetics of urate-lowering therapy. Key findings include the reporting of 28 urate-associated loci, the discovery that ABCG2 plays a central role on extra-renal uric acid excretion, the identification of genes associated with development of gout in the context of hyperuricaemia, recognition that ABCG2 variants influence allopurinol response, and the impact of HLA-B*5801 testing in reducing the prevalence of allopurinol hypersensitivity in high-risk populations. These advances, together with the reducing cost of whole genome sequencing, mean that integrated personalised medicine approaches may soon be possible in clinical practice. Genetic data may inform assessment of disease prognosis in individuals with hyperuricaemia or established gout, personalised lifestyle advice, selection and dosing of urate-lowering therapy, and prevention of serious medication adverse effects. In this article, we summarise the discoveries from genome-wide association studies and discuss the potential for translation of these findings into clinical practice.
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Affiliation(s)
- Nicola Dalbeth
- Department of Medicine, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Rd, Grafton, Auckland, 1023, New Zealand.
| | - Lisa K Stamp
- Department of Medicine, University of Otago, Christchurch, New Zealand
| | - Tony R Merriman
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
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Kuwabara M, Niwa K, Ohtahara A, Hamada T, Miyazaki S, Mizuta E, Ogino K, Hisatome I. Prevalence and complications of hypouricemia in a general population: A large-scale cross-sectional study in Japan. PLoS One 2017; 12:e0176055. [PMID: 28448596 PMCID: PMC5407834 DOI: 10.1371/journal.pone.0176055] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 04/04/2017] [Indexed: 11/18/2022] Open
Abstract
BACKGROUNDS Hypouricemia was reported as a risk factor for exercise-induced acute renal injury (EIAKI) and urinary stones. However, the prevalence of kidney diseases among hypouricemic subjects has not been evaluated. This study was conducted to clarify the prevalence of hypouricemia and the association of hypouricemia with kidney diseases by using a large-scale Japanese population data. METHODS This study is a retrospective cross-sectional study at the Center for Preventive Medicine, St. Luke's International Hospital, Tokyo, Japan, and Sanin Rousai Hospital, Yonago, Japan. We analyzed the medical records of 90,143 Japanese subjects at the center in St. Luke's International Hospital, Tokyo, and 4,837 subjects in Sanin Rousai Hospital, Yonago, who underwent annual regular health check-up between January 2004 and June 2010. We defined hypouricemia as serum uric acid level of ≤2.0 mg/dL. We checked the medical history of all the study subjects and compared the rates of complications including urinary stones and kidney diseases among those with or without hypouricemia. RESULTS The prevalence of hypouricemia was 0.19% in St. Luke's International Hospital, Tokyo, and 0.58% in Sanin Rousai Hospital, Yonago. The prevalence of hypouricemia in women was larger than that in men both in Tokyo (0.31% vs 0.068%, p<0.001) and in Yonago (1.237% vs 0.318%, p<0.001). Among 172 hypouricemic subjects (30 men), the rates of previous urinary stones and kidney diseases (including nephritis/nephrosis) were 1.2% (3.3% men, 0.7% women) and 2.3% (10% men, 0.7% women), respectively. Hypouricemic men had a 9-fold higher rate of previously having kidney diseases compared to non-hypouricemic men (p<0.001). However, the rates of other diseases including urinary stones were not significantly different between the two groups. CONCLUSIONS Hypouricemia was associated with a history of kidney disease especially in men.
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Affiliation(s)
- Masanari Kuwabara
- Department of Cardiology, Toranomon Hospital, Tokyo, Japan
- Division of Renal Diseases and Hypertension, School of Medicine, University of Colorado Denver, Aurora, Colorado, United States of America
- Department of Cardiology, Cardiovascular Center, St. Luke's International Hospital, Tokyo, Japan
- * E-mail:
| | - Koichiro Niwa
- Department of Cardiology, Cardiovascular Center, St. Luke's International Hospital, Tokyo, Japan
| | - Akira Ohtahara
- Department of Cardiology, Sanin Rosai Hospital, Yonago, Tottori, Japan
| | - Toshihiro Hamada
- Department of Community-Based Family Medicine, Tottori University Faculty of Medicine, Yonago, Tottori, Japan
| | - Satoshi Miyazaki
- Department of Cardiovascular Medicine, Masao Fujii Memorial Hospital, Kurayoshi, Tottori, Japan
| | - Einosuke Mizuta
- Department of Cardiology, Sanin Rosai Hospital, Yonago, Tottori, Japan
| | - Kazuhide Ogino
- Department of Clinical Laboratory, Tottori University Hospital, Yonago, Tottori, Japan
| | - Ichiro Hisatome
- Division of Regenerative Medicine and Therapeutics, Institute of Regenerative Medicine and Biofunction, Tottori University Graduate School of Medical Sciences, Yonago, Tottori, Japan
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Mancikova A, Krylov V, Hurba O, Sebesta I, Nakamura M, Ichida K, Stiburkova B. Functional analysis of novel allelic variants in URAT1 and GLUT9 causing renal hypouricemia type 1 and 2. Clin Exp Nephrol 2015; 20:578-584. [DOI: 10.1007/s10157-015-1186-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 10/13/2015] [Indexed: 11/28/2022]
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Hereditary Renal Hypouricemia Type 1 and Autosomal Dominant Polycystic Kidney Disease. Am J Med Sci 2015; 350:268-71. [DOI: 10.1097/maj.0000000000000550] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Ware EB, Riehle E, Smith JA, Zhao W, Turner ST, Kardia SLR, Lieske JC. SLC2A9 Genotype Is Associated with SLC2A9 Gene Expression and Urinary Uric Acid Concentration. PLoS One 2015; 10:e0128593. [PMID: 26167684 PMCID: PMC4500555 DOI: 10.1371/journal.pone.0128593] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 04/28/2015] [Indexed: 12/17/2022] Open
Abstract
Objectives SLC2A9 gene variants have been associated with urinary uric acid (UA) concentration, but little is known about the functional mechanism linking these gene variants with UA. SLC2A9 encodes a UA transporter present in the proximal tubule of the kidney, and gene expression levels of SLC2A9 and other genes in the uricosuric pathway (ABCG2, SLC17A1, SLC17A3, and SLC22A12) could potentially mediate the relationship between SLC2A9 gene variants and urinary UA excretion. Methods The association between urinary UA concentrations and single nucleotide polymorphisms (SNPs) within the SLC2A9 gene region, expression levels of genes in the uricosuric pathway, and dietary protein intake were analyzed for a sample of non-Hispanic white participants from the Genetic Epidemiology Network of Arteriopathy (GENOA) cohort. The SLC2A9 SNP most significantly associated with urinary UA concentration was then tested for associations with gene expression levels from uric acid absorption/secretion associated genes. Models including interactions between dietary protein (total, animal, and vegetable) and genetic factors were also assessed. Results The most significant SLC2A9 SNP associated with urinary UA (rs12509955, corrected p = 0.001) was also associated with SLC2A9 gene expression levels (corrected p = 0.0084); however, SLC2A9 gene expression levels were not significantly associated with urinary UA concentrations (p = 0.509). The interactions between rs12509955 and total dietary protein, and SLC2A9 gene-level gene expression and dietary vegetable protein on the outcome of urinary UA were marginally significant (p = 0.11 and p = 0.07, respectively). Gene expression level of one SLC2A9 transcript had a significant interaction with dietary animal protein (SLC2A9-001 ENST00000506583, p = 0.01) and a marginally significant interaction with total dietary protein (p = 0.07) on urinary UA. Conclusion Our results illustrate that SNPs in the SLC2A9 gene influence SLC2A9 gene expression as well as urinary UA excretion. Evidence is also suggestive that gene-by-diet interactions may disproportionately increase urinary UA in genetically susceptible individuals that consume higher amounts of protein.
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Affiliation(s)
- Erin B. Ware
- Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, MI, United States of America
- Institute for Social Research, University of Michigan, Ann Arbor, MI, United States of America
| | - Ellen Riehle
- Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, MI, United States of America
| | - Jennifer A. Smith
- Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, MI, United States of America
| | - Wei Zhao
- Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, MI, United States of America
| | - Stephen T. Turner
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, United States of America
| | - Sharon L. R. Kardia
- Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, MI, United States of America
- * E-mail:
| | - John C. Lieske
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, United States of America
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States of America
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Mraz M, Hurba O, Bartl J, Dolezel Z, Marinaki A, Fairbanks L, Stiburkova B. Modern diagnostic approach to hereditary xanthinuria. Urolithiasis 2014; 43:61-7. [PMID: 25370766 DOI: 10.1007/s00240-014-0734-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Accepted: 10/15/2014] [Indexed: 11/25/2022]
Abstract
Hereditary xanthinuria (HX) is a rare inherited disorder caused by a deficiency of xanthine dehydrogenase/oxidase (XDH/XO). Missing XDH/XO activity leads to undetectable levels of uric acid excessively replaced by xanthine in serum/urine. The allopurinol loading test has been traditionally used to differentiate between HX types I and II. Final confirmation of HX has been based on the biopsy finding of the absent XDH/XO activity in the small intestine or liver. We present the clinical, biochemical, ultrasound and molecular genetics findings in three new patients with HX and suggest a simple three-step approach to be used for diagnosis, typing and confirmation of HX. In the first step, the diagnosis of HX is determined by extremely low serum/urinary uric acid excessively replaced by xanthine. Second, HX is typed using urinary metabolomics. Finally, the results are confirmed by molecular genetics. We advocate for this safe and non-invasive diagnostic algorithm instead of the traditional allopurinol loading test and intestinal or liver biopsy used in the past.
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Affiliation(s)
- Martin Mraz
- Department of Nephrology, Birmingham Children's Hospital NHS Foundation Trust, Birmingham, UK
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Hurba O, Mancikova A, Krylov V, Pavlikova M, Pavelka K, Stibůrková B. Complex analysis of urate transporters SLC2A9, SLC22A12 and functional characterization of non-synonymous allelic variants of GLUT9 in the Czech population: no evidence of effect on hyperuricemia and gout. PLoS One 2014; 9:e107902. [PMID: 25268603 PMCID: PMC4182324 DOI: 10.1371/journal.pone.0107902] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Accepted: 08/18/2014] [Indexed: 11/24/2022] Open
Abstract
Objective Using European descent Czech populations, we performed a study of SLC2A9 and SLC22A12 genes previously identified as being associated with serum uric acid concentrations and gout. This is the first study of the impact of non-synonymous allelic variants on the function of GLUT9 except for patients suffering from renal hypouricemia type 2. Methods The cohort consisted of 250 individuals (150 controls, 54 nonspecific hyperuricemics and 46 primary gout and/or hyperuricemia subjects). We analyzed 13 exons of SLC2A9 (GLUT9 variant 1 and GLUT9 variant 2) and 10 exons of SLC22A12 by PCR amplification and sequenced directly. Allelic variants were prepared and their urate uptake and subcellular localization were studied by Xenopus oocytes expression system. The functional studies were analyzed using the non-parametric Wilcoxon and Kruskall-Wallis tests; the association study used the Fisher exact test and linear regression approach. Results We identified a total of 52 sequence variants (12 unpublished). Eight non-synonymous allelic variants were found only in SLC2A9: rs6820230, rs2276961, rs144196049, rs112404957, rs73225891, rs16890979, rs3733591 and rs2280205. None of these variants showed any significant difference in the expression of GLUT9 and in urate transport. In the association study, eight variants showed a possible association with hyperuricemia. However, seven of these were in introns and the one exon located variant, rs7932775, did not show a statistically significant association with serum uric acid concentration. Conclusion Our results did not confirm any effect of SLC22A12 and SLC2A9 variants on serum uric acid concentration. Our complex approach using association analysis together with functional and immunohistochemical characterization of non-synonymous allelic variants did not show any influence on expression, subcellular localization and urate uptake of GLUT9.
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Affiliation(s)
- Olha Hurba
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague, Prague, Czech Republic
| | - Andrea Mancikova
- Charles University in Prague, Faculty of Science, Department of Cell Biology, Prague, Czech Republic
| | - Vladimir Krylov
- Charles University in Prague, Faculty of Science, Department of Cell Biology, Prague, Czech Republic
| | - Marketa Pavlikova
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague, Prague, Czech Republic
| | | | - Blanka Stibůrková
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague, Prague, Czech Republic
- Institute of Rheumatology, Prague, Czech Republic
- * E-mail:
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Stibůrková B, Pavlíková M, Sokolová J, Kožich V. Metabolic syndrome, alcohol consumption and genetic factors are associated with serum uric acid concentration. PLoS One 2014; 9:e97646. [PMID: 24827988 PMCID: PMC4020828 DOI: 10.1371/journal.pone.0097646] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Accepted: 04/22/2014] [Indexed: 01/22/2023] Open
Abstract
OBJECTIVE Uric acid is the end product of purine metabolism in humans, and increased serum uric acid concentrations lead to gout. The objective of the current study was to identify factors that are independently associated with serum uric acid concentrations in a cohort of Czech control individuals. METHODS The cohort consisted of 589 healthy subjects aged 18-65 years. We studied the associations between the serum uric acid concentration and the following: (i) demographic, anthropometric and other variables previously reported to be associated with serum uric acid concentrations; (ii) the presence of metabolic syndrome and the levels of metabolic syndrome components; and (iii) selected genetic variants of the MTHFR (c.665C>T, c.1286A>C), SLC2A9 (c.844G>A, c.881G>A) and ABCG2 genes (c.421C>A). A backward model selection procedure was used to build two multiple linear regression models; in the second model, the number of metabolic syndrome criteria that were met replaced the metabolic syndrome-related variables. RESULTS The models had coefficients of determination of 0.59 and 0.53. The serum uric acid concentration strongly correlated with conventional determinants including male sex, and with metabolic syndrome-related variables. In the simplified second model, the serum uric acid concentration positively correlated with the number of metabolic syndrome criteria that were met, and this model retained the explanatory power of the first model. Moderate wine drinking did not increase serum uric acid concentrations, and the urate transporter ABCG2, unlike MTHFR, was a genetic determinant of serum uric acid concentrations. CONCLUSION Metabolic syndrome, moderate wine drinking and the c.421C>A variant in the ABCG gene are independently associated with the serum uric acid concentration. Our model indicates that uric acid should be clinically monitored in persons with metabolic syndrome.
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Affiliation(s)
- Blanka Stibůrková
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague, Prague, Czech Republic
| | - Markéta Pavlíková
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague, Prague, Czech Republic
| | - Jitka Sokolová
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague, Prague, Czech Republic
| | - Viktor Kožich
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague, Prague, Czech Republic
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Shen H, Feng C, Jin X, Mao J, Fu H, Gu W, Liu A, Shu Q, Du L. Recurrent exercise-induced acute kidney injury by idiopathic renal hypouricemia with a novel mutation in the SLC2A9 gene and literature review. BMC Pediatr 2014; 14:73. [PMID: 24628802 PMCID: PMC3984694 DOI: 10.1186/1471-2431-14-73] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Accepted: 03/06/2014] [Indexed: 11/15/2022] Open
Abstract
Background Idiopathic renal hypouricemia (iRHUC) is an autosomal recessive hereditary disorder, characterized by impaired tubular uric acid transport, re-absorption insufficiency and/or the acceleration of secretions. Some patients present with severe complications, such as exercise-induced acute kidney injury (EIAKI) and nephrolithiasis. Case presentation Herein, we report the case of a girl with severe iRHUC (serum urate 0.05 mg/dL, fractional excretion of uric acid 295.99%) associated with recurrent EIAKI, in whom the disease was caused by a homozygous mutation (g.68G > A in exon 3) in the SLC2A9 gene. Her family members (father, mother and brother) carried the same mutation but were heterozygous, without any signs of severe hypouricemia. Conclusions Our findings indicate that iRHUC is a rare disorder but that it should also be considered in patients with EIAKI, especially in those patients who manifest with moderately elevated or normal serum concentrations of uric acid during the acute phase of AKI. Mutational screening of the SLC2A9 gene is necessary for the diagnosis of iRHUC, and homozygous mutations of the SLC2A9 alleles can cause severe hypouricemia. Careful attention should be paid to any signs of hypouricemia during the recovery phase of AKI and long-term follow-up.
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Affiliation(s)
| | | | | | - Jianhua Mao
- Department of Nephrology, The Children's Hospital of Zhejiang University School of Medicine, Hangzhou 310003, Zhejiang Province, China.
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Abstract
PURPOSE OF REVIEW Recent advances in genome technology have provided us with a list of molecules affecting urate handling in humans, many of which are unlikely to be identified through traditional physiological approach alone. Although this article is focused on urate, this can be viewed as a successful model of genomics-physiology collaboration. RECENT FINDINGS URATv1/GLUT9 (SLC2A9) is shown to play a critical role in urate reabsorption at the proximal tubule, probably more prominent than its partner URAT1 (SLC22A12). The major site of action of ABCG2 (ABCG2), an influential urate secretion transporter, has been shown to be the intestine rather than the kidney proximal tubule. Accordingly, hypofunction of ABCG2 leads to increased fractional excretion of urate, a finding traditionally interpreted as overproduction hyperuricemia. Some SLC17 family members secrete urate in the kidney or intestine. OAT2 (SLC22A7) may take up urate from blood to the proximal tubular cell. In addition, how a common single-nucleotide polymorphisms in ABCG2 affects its function has been elucidated. SUMMARY A finer grained picture of urate handling in the human body is now emerging, which will help choosing novel targets for urate-lowering therapy.
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Jeannin G, Chiarelli N, Gaggiotti M, Ritelli M, Maiorca P, Quinzani S, Verzeletti F, Possenti S, Colombi M, Cancarini G. Recurrent exercise-induced acute renal failure in a young Pakistani man with severe renal hypouricemia and SLC2A9 compound heterozygosity. BMC MEDICAL GENETICS 2014; 15:3. [PMID: 24397858 PMCID: PMC3890613 DOI: 10.1186/1471-2350-15-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Accepted: 12/26/2013] [Indexed: 11/24/2022]
Abstract
Background Familial renal hypouricemia (RHUC) is a hereditary disease characterized by hypouricemia, high renal fractional excretion of uric acid (FE-UA) and can be complicated by acute kidney failure and nephrolithiasis. Loss-of-function mutations in the SLC22A12 gene cause renal hypouricemia type 1 (RHUC1), whereas renal hypouricemia type 2 (RHUC2) is caused by mutations in the SLC2A9 gene. Case presentation We describe a 24-year-old Pakistani man who was admitted twice to our hospital for severe exercise-induced acute renal failure (EIARF), abdominal pain and fever; he had very low serum UA levels (0.2 mg/dl the first time and 0.09 mg/dl the second time) and high FE-UA (200% and 732% respectively), suggestive of RHUC. Mutational analyses of both urate transporters revealed a new compound heterozygosity for two distinct missense mutations in the SLC2A9 gene: p.Arg380Trp, already identified in heterozygosity, and p.Gly216Arg, previously found in homozygosity or compound heterozygosity in some RHUC2 patients. Compared with previously reported patients harbouring these mutations, our proband showed the highest FE-UA levels, suggesting that the combination of p.Arg380Trp and p.Gly216Arg mutations most severely affects the renal handling of UA. Conclusions The clinical and molecular findings from this patient and a review of the literature provide new insights into the genotype-phenotype correlation of this disorder, supporting the evidence of an autosomal recessive inheritance pattern for RHUC2. Further investigations into the functional properties of GLUT9, URAT1 and other urate transporters are required to assess their potential research and clinical implications.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Marina Colombi
- Division of Biology and Genetics, Department of Molecular and Translational Medicine, University of Brescia, Viale Europa 11, 25123 Brescia, Italy.
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Kimura T, Takahashi M, Yan K, Sakurai H. Expression of SLC2A9 isoforms in the kidney and their localization in polarized epithelial cells. PLoS One 2014; 9:e84996. [PMID: 24409316 PMCID: PMC3883675 DOI: 10.1371/journal.pone.0084996] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Accepted: 11/27/2013] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Many genome-wide association studies pointed out that SLC2A9 gene, which encodes a voltage-driven urate transporter, SLC2A9/GLUT9 (a.k.a. URATv1), as one of the most influential genes for serum urate levels. SLC2A9 is reported to encode two splice variants: SLC2A9-S (512 amino acids) and SLC2A9-L (540 amino acids), only difference being at their N-termini. We investigated isoform-specific localization of SLC2A9 in the human kidney and role of N-terminal amino acids in differential sorting in vitro. METHODOLOGY/PRINCIPAL FINDINGS Isoform specific antibodies against SLC2A9 were developed and human kidney sections were stained. SLC2A9-S was expressed in the apical side of the collecting duct while SLC2A9-L was expressed in the basolateral side of the proximal tubule. GFP fused SLC2A9s were expressed in MDCK cells and intracellular localization was observed. SLC2A9-S was expressed at both apical and basolateral membranes, whereas SLC2A9-L was expressed only at the basolateral membrane. Although SLC2A9-L has a putative di-leucine motif at 33th and 34th leucine, deletion of the motif or replacement of leucine did not affect its subcellular localization. When up to 16 amino acids were removed from the N-terminal of SLC2A9-S or when up to 25 amino acids were removed from the N-terminal of SLC2A9-L, there was no change in their sorting. Deletion of 20 amino acids from SLC2A9-S was not expressed in the cell. More than 30 amino acids deletion from SLC2A9-L resulted in expression at both apical and basolateral membranes as well as in the lysosome. When amino acids from 25th and 30th were changed to alanine in SLC2A9-L, expression pattern was the same as wild-type. CONCLUSIONS/SIGNIFICANCE SLC2A9-L was expressed in the basolateral membrane of kidney proximal tubules in humans and this isoform is likely to responsible for urate reabsorption. N-terminal amino acids unique to each isoform played an important role in protein stability and trafficking.
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Affiliation(s)
- Toru Kimura
- Department of Pharmacology and Toxicology, Kyorin University School of Medicine, Mitaka, Tokyo, Japan
| | - Michi Takahashi
- Department of Pharmacology and Toxicology, Kyorin University School of Medicine, Mitaka, Tokyo, Japan
| | - Kunimasa Yan
- Department of Pediatrics, Kyorin University School of Medicine, Mitaka, Tokyo, Japan
| | - Hiroyuki Sakurai
- Department of Pharmacology and Toxicology, Kyorin University School of Medicine, Mitaka, Tokyo, Japan
- * E-mail:
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Bhasin B, Stiburkova B, De Castro-Pretelt M, Beck N, Bodurtha JN, Atta MG. Hereditary renal hypouricemia: a new role for allopurinol? Am J Med 2014; 127:e3-4. [PMID: 24262806 DOI: 10.1016/j.amjmed.2013.08.025] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Revised: 08/23/2013] [Accepted: 08/24/2013] [Indexed: 12/01/2022]
Affiliation(s)
- Bhavna Bhasin
- Division of Nephrology, Johns Hopkins University School of Medicine, Baltimore, Md
| | - Blanka Stiburkova
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University in Prague, General University Hospital in Prague, Prague, Czech Republic
| | - Mauricio De Castro-Pretelt
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Md
| | - Natalie Beck
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Md
| | - Joann N Bodurtha
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Md
| | - Mohamed G Atta
- Division of Nephrology, Johns Hopkins University School of Medicine, Baltimore, Md.
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Novel allelic variants and evidence for a prevalent mutation in URAT1 causing renal hypouricemia: biochemical, genetics and functional analysis. Eur J Hum Genet 2013; 21:1067-73. [PMID: 23386035 DOI: 10.1038/ejhg.2013.3] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 12/14/2012] [Accepted: 01/02/2013] [Indexed: 12/31/2022] Open
Abstract
Renal hypouricemia (RHUC) is a heterogeneous inherited disorder characterized by impaired tubular uric acid (UA) transport with severe complications, such as acute kidney injury (AKI). Type 1 is caused by a loss-of-function mutation in the SLC22A12 gene (URAT1), type 2 in the SLC2A9 gene (GLUT9). This article describes three Czech families with RHUC type 1. The serum UA in the probands was 0.9, 1.1 and 0.5 mg/dl and expressed as an increase in the fractional excretion of UA (48, 43 and 39%). The sequencing analysis of SLC22A12 revealed three novel variants: p.G366R, p.T467M and a deletion p.L415_G417del. A detailed metabolic investigation in proband C for progressive visual failure supported suspicion of neuronal ceroid lipofuscinosis type 7 conditioned by the mutation in the MFSD8 gene. Functional studies showed significantly decreased urate uptake and a mis-localized URAT1 signal in p.G366R, p.L415_G417del and p.T467M. Furthermore, colocalization studies showed accumulation of URAT1 protein in the endoplasmic reticulum. The findings suggest that loss-of-function mutations cause RHUC via loss of UA absorption partly by protein misfolding. However, they do not necessarily lead to AKI and a possible genotype-phenotype correlation was not proposed. Furthermore, results confirm an uneven geographical and ethnic distribution of SLC22A12 variants; the p.L415_G417del mutation predominates in the Roma ethnic group in the Czech Republic.
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Novel URAT1 mutations caused acute renal failure after exercise in two Chinese families with renal hypouricemia. Gene 2013; 512:97-101. [DOI: 10.1016/j.gene.2012.09.115] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2012] [Revised: 09/18/2012] [Accepted: 09/30/2012] [Indexed: 11/22/2022]
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Affiliation(s)
- Pascal Richette
- Université Paris 7, UFR médicale, Assistance Publique-Hôpitaux de Paris, Hôpital Lariboisière, Fédération de Rhumatologie,
75475 Paris Cedex 10, France ;
| | - Ricardo Garay
- INSERM U999, Hôpital Marie-Lannelongue & University Paris-Sud,
Le Plessis-Robinson, France
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Sebesta I. Genetic disorders resulting in hyper- or hypouricemia. Adv Chronic Kidney Dis 2012; 19:398-403. [PMID: 23089275 DOI: 10.1053/j.ackd.2012.06.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2012] [Revised: 06/15/2012] [Accepted: 06/18/2012] [Indexed: 11/11/2022]
Abstract
Serum uric acid concentrations are governed by the balance of urate production and excretion. Besides well-known secondary causes of hyperuricemia, such as myeloproliferative diseases, decreased renal function, and excessive dietary purine intake, there are a number of genetic disorders that result in hyper- or hypouricemia. Renal impairment in these disorders may be associated with the development of chronic kidney disease, acute kidney injury, or urate nephrolithiasis. These conditions are frequently misdiagnosed, not because the diagnosis is complicated and difficult to ascertain, but rather because of a lack of awareness of the particular condition. The first important step in the diagnosis is obtaining a detailed family history, with evaluation of serum and urinary urate concentrations. This review will aid physicians in identifying these inherited kidney disorders associated with hyperuricemia and hypouricemia. Identification of these conditions will help to explain the pathogenesis of different types of gout, and may extend insights into the urate transport and chronic kidney disease.
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Stiburkova B, Bleyer AJ. Changes in serum urate and urate excretion with age. Adv Chronic Kidney Dis 2012; 19:372-6. [PMID: 23089271 DOI: 10.1053/j.ackd.2012.07.010] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Revised: 07/18/2012] [Accepted: 07/18/2012] [Indexed: 11/11/2022]
Abstract
A cross-sectional study was performed evaluating serum urate levels and fractional excretion of urate in a group of patients referred for screening for inherited metabolic disorders. From 2003 through 2010, serum urate, serum creatinine, urinary urate, and urinary creatinine levels were obtained as part of a research protocol to identify individuals with inherited metabolic disorders. These values were compared with individuals with uromodulin-associated kidney disease (UAKD). Laboratory studies were evaluated on 1274 individuals. The fractional excretion of urate was very high in infancy (27 ± 21% in males and 29 ± 25% in females). The high fractional excretion declined rapidly over the first several months of life, together with a decline in serum urate levels. The mean fractional excretion was approximately 8% during childhood. It then remained stable in females but decreased in males to 5.9 ± 5.6% in adolescence and 5.3 ± 3.8% in adulthood. Serum urate levels in childhood were influenced by age and kidney function but not gender. In adulthood, serum urate was influenced by age, gender, and estimated glomerular filtration rate. Although patients with UAKD had lower fractional excretions of urate than individuals with normal kidney function, there was considerable overlap.
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Stiburkova B, Taylor J, Marinaki AM, Sebesta I. Acute kidney injury in two children caused by renal hypouricaemia type 2. Pediatr Nephrol 2012; 27:1411-5. [PMID: 22527535 DOI: 10.1007/s00467-012-2174-0] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Revised: 03/27/2012] [Accepted: 03/28/2012] [Indexed: 11/26/2022]
Abstract
BACKGROUND Renal hypouricaemia is a heterogeneous inherited disorder characterized by impaired tubular uric acid transport with severe complications, such as acute kidney injury and nephrolithiasis. Type 1 is caused by a loss-of-function mutation in the SLC22A12 gene (OMIM #220150), while type 2 is caused by defects in the SLC2A9 gene (OMIM #612076). CASE-DIAGNOSIS/TREATMENT The cases of two children, a 12- and a 14-year-old boy with acute kidney injury (proband 1: urea 9.4 mmol/l, creatinine 226 μmol/l; proband 2: urea 11.7 mmol/l, creatinine 202 μmol/l) are described. Both are offspring of nonconsanguineous couples in the UK. The concentrations of serum uric acid were consistently below the normal range (0.03 and 0.04 mmol/l) and expressed as an increase in the fractional excretion of uric acid (46 and 93 %). CONCLUSIONS A sequencing analysis of the coding region of uric acid transporters SLC22A12 and SLC2A9 was performed. Analysis of genomic DNA revealed two unpublished missense transitions, p.G216R and p.N333S in the SLC2A9 gene. No sequence variants in SLC22A12 were found. Our findings suggest that homozygous and/or compound heterozygous loss-of-function mutations p.G216R and p.N333S cause renal hypouricaemia via loss of uric acid absorption and do lead to acute kidney injury.
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Affiliation(s)
- Blanka Stiburkova
- Institute of Inherited Metabolic Disorders, Charles University in Prague, First Faculty of Medicine and General University Hospital in Prague, Ke Karlovu 2, 128 53, Prague 2, Czech Republic.
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Sebesta I, Stiburkova B, Bartl J, Ichida K, Hosoyamada M, Taylor J, Marinaki A. Diagnostic tests for primary renal hypouricemia. NUCLEOSIDES NUCLEOTIDES & NUCLEIC ACIDS 2012; 30:1112-6. [PMID: 22132965 DOI: 10.1080/15257770.2011.611483] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
Abstract
Primary renal hypouricemia is a genetic disorder characterized by defective renal uric acid (UA) reabsorption with complications such as nephrolithiasis and exercise-induced acute renal failure. The known causes are: defects in the SLC22A12 gene, encoding the human urate transporter 1 (hURAT1), and also impairment of voltage urate transporter (URATv1), encoded by SLC2A9 (GLUT9) gene. Diagnosis is based on hypouricemia (<119 μmol/L) and increased fractional excretion of UA (>10%). To date, the cases with mutations in hURAT1 gene have been reported in East Asia only. More than 100 Japanese patients have been described. Hypouricemia is sometimes overlooked; therefore, we have set up the flowchart for this disorder. The patients were selected for molecular analysis from 620 Czech hypouricemic patients. Secondary causes of hyperuricosuric hypouricemia were excluded. The estimations of (1) serum UA, (2) excretion fraction of UA, and (3) analysis of hURAT1 and URATv1 genes follow. Three transitions and one deletion (four times) in SLC22A12 gene and one nucleotide insertion in SLC2A9 gene in seven Czech patients were found. Three patients had acute renal failure and urate nephrolithiasis. In addition, five nonsynonymous sequence variants and three nonsynonymous sequence variants in SLC2A9 gene were found in two UK patients suffering from acute renal failure. Our finding of the defects in SLC22A12 and SLC2A9 genes gives further evidence of the causative genes of primary renal hypouricemia and supports their important role in regulation of serum urate levels in humans.
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Affiliation(s)
- Ivan Sebesta
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University, Prague, Czech Republic.
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Stiburkova B, Krijt J, Vyletal P, Bartl J, Gerhatova E, Korinek M, Sebesta I. Novel mutations in xanthine dehydrogenase/oxidase cause severe hypouricemia: biochemical and molecular genetic analysis in two Czech families with xanthinuria type I. Clin Chim Acta 2011; 413:93-9. [PMID: 21963464 DOI: 10.1016/j.cca.2011.08.038] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Revised: 08/29/2011] [Accepted: 08/30/2011] [Indexed: 02/04/2023]
Abstract
BACKGROUND The article describes the clinical, biochemical, enzymological and molecular genetics findings in two patients from two families with xanthinuria type I. METHODS Biochemical analysis using high performance liquid chromatography, allopurinol loading test and analysis of xanthine oxidase activity in plasma and of uromodulin excretion in urine were performed. Sequencing analysis of the xanthine dehydrogenase gene and the haplotype and statistical analyses of consanguinity were performed. RESULTS Probands showed extremely low concentrations of uric acid, on seven occasions under the limit of detection. The concentration of uric acid in 38-year-old female was 15 μmol/L in serum and 0.04 mmol/L in urine. Excretion of xanthine in urine was 170 mmol/mol creatinine. The concentration of uric acid in 25-year-old male was 0.03 mmol/L in urine. Excretion of xanthine in urine was 141 mmol/mol creatinine. The allopurinol loading test confirmed xanthinuria type I. The xanthine oxidase activities in patients were 0 and 0.4 pmol/h/mL of plasma. We found three nonsense changes: p.P214QfsX4 and unpublished p.R825X and p.R881X. CONCLUSIONS We found two nonconsanguineous compound heterozygotes with xanthinuria type I caused by three nonsense changes. The methods used did not confirm consanguinity in the probands, thus there might be an unconfirmed biological relationship or mutational hotspot.
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Affiliation(s)
- Blanka Stiburkova
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague, Prague, Czech Republic.
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Hamajima N, Okada R, Kawai S, Hishida A, Morita E, Yin G, Wakai K, Matsuo H, Inoue H, Takada Y, Asai Y, Mori A, Naito M. Significant association of serum uric acid levels with SLC2A9 rs11722228 among a Japanese population. Mol Genet Metab 2011; 103:378-82. [PMID: 21511506 DOI: 10.1016/j.ymgme.2011.04.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2011] [Revised: 04/03/2011] [Accepted: 04/03/2011] [Indexed: 12/13/2022]
Abstract
Genome-wide association studies identified that SLC2A9 (GLUT9) gene polymorphisms were associated with serum uric acid (SUA) levels. Among the Japanese, a C/T polymorphism in intron 8 (rs11722228) was reported to be highly significant, though the function and strength of association were unknown. This study aimed to confirm the association, estimating the means of SUA according to the genotype, as well as OR of the genotype. Subjects were 5024 health checkup examinees (3413 males and 1611 females) aged 35 to 69 years with creatinine <2.0 mg/dL. Since SLC22A12 258X allele and ABCG2 126X allele are known to influence SUA levels strongly, the subjects with SLC22A12 258WW and ABCG2 126QQ (3082 males and 1453 females, in total 4535 subjects) were selected. The genotype frequency of SLC2A9 rs11722228 was 2184 for CC, 1947 for CT, and 404 for TT, being in Hardy-Weinberg equilibrium (p=0.312). Mean SUA was 6.10 mg/dL for CC, 6.25 mg/dL for CT, and 6.45 mg/dL for TT among males (p=1.5E-6), and 4.34 mg/dL, 4.59 mg/dL, and 4.87 mg/dL among females (p=4.6E-11), respectively. Males with SUA less than 5.0 mg/dL were 14.7% for CC, 10.6% for CT, and 7.8% for TT (p=2.3E-4), and females with SUA less than 4.0 mg/dL were 34.1%, 25.5%, and 15.4% (p=3.7E-6), respectively. This study was the first report to estimate the impact of SLC2A9 rs11722228 on SUA levels. Since the allele frequency of rs11722228 is similar among different ethnic groups, the impact remains to be examined in other ethnic groups.
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Affiliation(s)
- Nobuyuki Hamajima
- Department of Preventive Medicine, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan.
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