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Qu Y, Hao L, Wang X. A young-onset type 2 diabetic Chinese girl with familial renal glycosuria caused by a novel mutation in SLC5A2: A case report. J Diabetes 2023; 15:622-626. [PMID: 37193603 PMCID: PMC10345970 DOI: 10.1111/1753-0407.13410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 04/07/2023] [Accepted: 04/20/2023] [Indexed: 05/18/2023] Open
Affiliation(s)
- Yuqing Qu
- Department of EndocrinologyYantai Yuhuangding HospitalYantaiChina
- Department of EndocrinologyThe First Medical Center of Chinese PLA General HospitalBeijingChina
| | - Limei Hao
- Department of EndocrinologyThe First Medical Center of Chinese PLA General HospitalBeijingChina
- Department of EndocrinologyDingzhou People's HospitalDingzhouChina
| | - Xianling Wang
- Department of EndocrinologyThe First Medical Center of Chinese PLA General HospitalBeijingChina
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2
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Huang H, Wu X, He Q, Liang X, Ding Y, Li Z, Ren Z, Bao Y. Case report: Identification of three novel compound heterozygous SGLT2 variants in three Chinese pediatric patients with familial renal glucosuria. Front Pediatr 2022; 10:996946. [PMID: 36518778 PMCID: PMC9742408 DOI: 10.3389/fped.2022.996946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 11/11/2022] [Indexed: 11/29/2022] Open
Abstract
Familial renal glucosuria (FRG) is a rare genetic condition featured by isolated glucosuria without hyperglycemia or other kidney diseases. It is caused by pathogenic mutations of the SGLT2 (Sodium-Glucose Cotransporter 2) gene, whose protein product is responsible for reabsorbing the majority of glucose in the early proximal convoluted tubule. Hitherto, quite an array of variants of SGLT2 have been identified in patients of FRG. In this study, we performed whole exome sequencing on three Chinese pediatric patients with FRG and uncovered three compound heterozygous variants of SGLT2: c.1333C > T (p.Q445X) and c.1130-5 C > G; c.1438G > T (p.V480F) and c.346G > A (p.V116M); c.1175C > G (p.S392C) and c.1333C > T (p.Q445X). Among the total of five variants, c.1333C > T (p.Q445X), c.1438G > T (p.V480F) and c.1175C > G (p.S392C) represented novel variants that had not been reported in any genetic databases. All five variants had extremely low allele frequencies and the amino acids loci affected by missense variants were highly conserved in vertebrate species. Bioinformatic tools predicted that all five variants might disrupt the function of SGLT2, which were likely to be causal for FRG in these patients. Our findings expand the variant spectrum of SGLT2 associated with FRG and provide novel insights into mechanism of action of this transporter, which will aid in the development of novel SGLT2 inhibitors for treatment of type 2 diabetes and cardiovascular diseases.
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Affiliation(s)
- Huimei Huang
- Department of Nephrology, Xi'an Children's Hospital, The Affiliated Children's Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Xiantao Wu
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Xi'an Jiaotong University, Xi'an, China
| | - Qing He
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Xi'an Jiaotong University, Xi'an, China
| | - Xuqin Liang
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Xi'an Jiaotong University, Xi'an, China
| | - Yi Ding
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Xi'an Jiaotong University, Xi'an, China
| | - Zhijuan Li
- Department of Nephrology, Xi'an Children's Hospital, The Affiliated Children's Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Zhanping Ren
- Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, Xi'an, China.,Department of Cleft Lip and Palate Surgery, College of Stomatology, Xi'an Jiaotong University, Xi'an, China
| | - Ying Bao
- Department of Nephrology, Xi'an Children's Hospital, The Affiliated Children's Hospital of Xi'an Jiaotong University, Xi'an, China
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Ryznychuk MO, Pishak VP, Bacyuk-Ponych NV, Pishak OV. Hereditary tubulopathies accompanying polyuia. REGULATORY MECHANISMS IN BIOSYSTEMS 2021. [DOI: 10.15421/022161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Tubulopathies are a group of heterogeneous diseases that are manifested in the malfunction of the renal tubules. This review addresses tubulopathies associated with polyuria syndrome, namely renal glucosuria syndrome, nephrogenic diabetes insipidus and pseudohyperaldosteronism. Types of renal glucosuria are described, namely: type A, type B and the most severe type 0. Type A is characterized by a low filtration threshold and low glucose reabsorption. The type of inheritance is autosomal recessive. Type B, autosomal dominant, is characterized by uneven activity of glucose transport, in which its reabsorption is reduced only in some nephrons. That is, normal reabsorption of glucose is maintained, but the filtration threshold of the latter is reduced. Type 0 with a severe course is characterized by complete inability of epithelial cells of the proximal tubules to reabsorb glucose. Nephrogenic diabetes insipidus is a rare inherited disease caused by impaired response of the renal tubules to antidiuretic hormone (ADH). Depending on the degree of inability to concentrate urine, there are complete and partial forms. It is divided into nephrogenic diabetes insipidus type I (X-linked recessive); nephrogenic diabetes insipidus type II (autosomal recessive and autosomal dominant) and nephrogenic diabetes insipidus syndrome with dementia and intracerebral calcifications (type of inheritance remains unknown). Children with autosomal recessive type of inheritance suffer from the more severe disease course. Pseudohypoaldosteronism is characterized by a special condition of the renal tubules which is due to insufficient sensitivity of the tubular epithelium to aldosterone, which in turn leads to hyperaldosteronism, the development of hyponatremia, metabolic acidosis with hyperkalemia, polydipsia and polyuria, decreased sodium reabsorption and retardation of the child's physical development. The classification includes three syndromes of pseudohypoaldosteronism, namely: type I (PHA1), which is divided into PHA1A (autosomal dominant, renal), PHA1B (autosomal recessive, systemic); type II (PHA2; Gordon’s syndrome), type III (secondary), which develops as a result of renal pathology.
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Gyimesi G, Pujol-Giménez J, Kanai Y, Hediger MA. Sodium-coupled glucose transport, the SLC5 family, and therapeutically relevant inhibitors: from molecular discovery to clinical application. Pflugers Arch 2020; 472:1177-1206. [PMID: 32767111 PMCID: PMC7462921 DOI: 10.1007/s00424-020-02433-x] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 06/24/2020] [Accepted: 07/02/2020] [Indexed: 02/06/2023]
Abstract
Sodium glucose transporters (SGLTs) belong to the mammalian solute carrier family SLC5. This family includes 12 different members in human that mediate the transport of sugars, vitamins, amino acids, or smaller organic ions such as choline. The SLC5 family belongs to the sodium symporter family (SSS), which encompasses transporters from all kingdoms of life. It furthermore shares similarity to the structural fold of the APC (amino acid-polyamine-organocation) transporter family. Three decades after the first molecular identification of the intestinal Na+-glucose cotransporter SGLT1 by expression cloning, many new discoveries have evolved, from mechanistic analysis to molecular genetics, structural biology, drug discovery, and clinical applications. All of these advances have greatly influenced physiology and medicine. While SGLT1 is essential for fast absorption of glucose and galactose in the intestine, the expression of SGLT2 is largely confined to the early part of the kidney proximal tubules, where it reabsorbs the bulk part of filtered glucose. SGLT2 has been successfully exploited by the pharmaceutical industry to develop effective new drugs for the treatment of diabetic patients. These SGLT2 inhibitors, termed gliflozins, also exhibit favorable nephroprotective effects and likely also cardioprotective effects. In addition, given the recent finding that SGLT2 is also expressed in tumors of pancreas and prostate and in glioblastoma, this opens the door to potential new therapeutic strategies for cancer treatment by specifically targeting SGLT2. Likewise, further discoveries related to the functional association of other SGLTs of the SLC5 family to human pathologies will open the door to potential new therapeutic strategies. We furthermore hope that the herein summarized information about the physiological roles of SGLTs and the therapeutic benefits of the gliflozins will be useful for our readers to better understand the molecular basis of the beneficial effects of these inhibitors, also in the context of the tubuloglomerular feedback (TGF), and the renin-angiotensin system (RAS). The detailed mechanisms underlying the clinical benefits of SGLT2 inhibition by gliflozins still warrant further investigation that may serve as a basis for future drug development.
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Affiliation(s)
- Gergely Gyimesi
- Membrane Transport Discovery Lab, Department of Nephrology and Hypertension, and Department of Biomedical Research, Inselspital, University of Bern, Kinderklinik, Office D845, Freiburgstrasse 15, CH-3010, Bern, Switzerland
| | - Jonai Pujol-Giménez
- Membrane Transport Discovery Lab, Department of Nephrology and Hypertension, and Department of Biomedical Research, Inselspital, University of Bern, Kinderklinik, Office D845, Freiburgstrasse 15, CH-3010, Bern, Switzerland
| | - Yoshikatsu Kanai
- Department of Bio-system Pharmacology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Matthias A Hediger
- Membrane Transport Discovery Lab, Department of Nephrology and Hypertension, and Department of Biomedical Research, Inselspital, University of Bern, Kinderklinik, Office D845, Freiburgstrasse 15, CH-3010, Bern, Switzerland.
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5
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Yu L, Wu M, Hou P, Zhang H. SLC5A2 mutations, including two novel mutations, responsible for renal glucosuria in Chinese families. BMC Nephrol 2020; 21:69. [PMID: 32111189 PMCID: PMC7047355 DOI: 10.1186/s12882-020-01725-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Accepted: 02/14/2020] [Indexed: 11/26/2022] Open
Abstract
Background Familial renal glucosuria (FRG) is characterized by persistent glucosuria without other impairments of tubular function in the presence of normal serum glucose. SGLT2, which is almost exclusively expressed in the kidney, accounts for most of the glucose reabsorption. Recently, some studies have confirmed that SLC5A2 mutations are responsible for the pathogenesis of familial renal glucosuria, but FRG cases are still rare. Furthermore, there are a few reports about splice-site mutations in previous studies, but the effect of these variants at the mRNA level has hardly been verified. Methods Ten patients were recruited in our renal division because of persistent glucosuria, and clinical data of the patients and their family members were recorded as much as possible. The entire coding region and adjacent intronic segments of SLC5A2 were sequenced in FRG patients and their relatives. Permanent growing lymphoblastoid cell lines from FRG patients were established to better preserve genetic information. Results A total of nine different mutations were identified: IVS1-16C > A, c.305C > T/p.(A102V), c.395G > A/p.(R132H), c.736C > T/p.(P246S), c.886(−10_-31)delGCAAGCGGGCAGCTGAACGCCC, c.1152_1163delGGTCATGCTGGC/p.(Val385_Ala388del), c.1222G > T/p.(D408Y), c.1496G > A/p.(R499H) and c.1540C > T/p.(P514S); two novel mutations in SLC5A2, c.1222G > T/p.(D408Y) and c.1496G > A/p.(R499H), were identified in the Chinese FRG pedigrees. Ten individuals with heterozygous or compound heterozygous variants had glucosuria in the range of 3.1 to 37.6 g/d. Conclusion We screened ten additional Chinese FRG pedigrees for mutations in the SLC5A2 gene and found nine mutations, including two novel mutations. Most variants were private, but IVS1-16C > A and c.886(−10_-31) del may be high frequency splice-site mutations that could be preferentially screened when variants cannot be found in the SLC5A2 exon. Furthermore, we successfully established a permanent growing lymphoblastoid cell line from patients with FRG, which could facilitate further studies of the SLC5A2 gene. The current study provides a valuable clue for further research on the molecular mechanism of SGLT2.
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Affiliation(s)
- Lei Yu
- Renal Division, Inner Mongolia People's Hospital, Hohhot, Inner Mongolia, 010017, People's Republic of China.
| | - Meng Wu
- Department of Nephrology, Longyan First Hospital Affiliated to Fujian Medical University, Longyan, Fujian, 364000, People's Republic of China
| | - Ping Hou
- Renal Division, Peking University First Hospital; Peking University Institute of Nephrology; Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, 100034, People's Republic of China
| | - Hong Zhang
- Renal Division, Peking University First Hospital; Peking University Institute of Nephrology; Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, 100034, People's Republic of China
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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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7
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Li S, Yang Y, Huang L, Kong M, Yang Z. A novel compound heterozygous mutation in SLC5A2 contributes to familial renal glucosuria in a Chinese family, and a review of the relevant literature. Mol Med Rep 2019; 19:4364-4376. [PMID: 30942416 PMCID: PMC6472135 DOI: 10.3892/mmr.2019.10110] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2018] [Accepted: 02/21/2019] [Indexed: 12/17/2022] Open
Abstract
Familial renal glucosuria (FRG) is a rare condition that involves isolated glucosuria despite normal blood glucose levels. Mutations in the solute carrier family 5 member 2 (SLC5A2) gene, which encodes sodium-glucose cotransporter 2 (SGLT2), have been reported to be responsible for the disease. Genetic testing of the SLC5A2 gene was conducted in a Chinese family with FRG. A number of online tools were used to predict the potential effect of the identified mutations on SGLT2 function. Additionally, the SLC5A2 mutations previously reported in PubMed were summarized. A novel compound heterozygous mutation (c.514T>C, p.W172R; c.1540C>T, p.P514S) of the SLC5A2 gene in a Chinese child with FRG was identified. In total, 86 mutations of the SLC5A2 gene have been reported to be associated with FRG. The novel compound heterozygous mutation (c.514T>C, p.W172R; c.1540C>T, p.P514S) of the SLC5A2 gene may be responsible for the onset of FRG. The present study provides a starting point for further investigation of the molecular pathogenesis of the SLC5A2 gene mutation in patients with FRG.
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Affiliation(s)
- Shentang Li
- Department of Pediatrics, The Third Xiangya Hospital of Central South University, Changsha, Hunan 410013, P.R. China
| | - Yeyi Yang
- Department of Medicine, The Third Xiangya Hospital of Central South University, Changsha, Hunan 410013, P.R. China
| | - Lihua Huang
- Central Laboratory, The Third Xiangya Hospital of Central South University, Changsha, Hunan 410013, P.R. China
| | - Min Kong
- Department of Pediatrics, The Third Xiangya Hospital of Central South University, Changsha, Hunan 410013, P.R. China
| | - Zuocheng Yang
- Department of Pediatrics, The Third Xiangya Hospital of Central South University, Changsha, Hunan 410013, P.R. China
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8
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Wang X, Yu M, Wang T, Zhang H, Ping F, Zhang Q, Xu J, Feng K, Xiao X. Genetic analysis and literature review of Chinese patients with familial renal glucosuria: Identification of a novel SLC5A2 mutation. Clin Chim Acta 2017; 469:105-110. [DOI: 10.1016/j.cca.2017.03.027] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 03/12/2017] [Accepted: 03/28/2017] [Indexed: 11/26/2022]
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Kawasoe S, Maruguchi Y, Kajiya S, Uenomachi H, Miyata M, Kawasoe M, Kubozono T, Ohishi M. Mechanism of the blood pressure-lowering effect of sodium-glucose cotransporter 2 inhibitors in obese patients with type 2 diabetes. BMC Pharmacol Toxicol 2017; 18:23. [PMID: 28391776 PMCID: PMC5385592 DOI: 10.1186/s40360-017-0125-x] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 02/28/2017] [Indexed: 02/06/2023] Open
Abstract
Background Sodium-glucose cotransporter 2 (SGLT2) inhibitors are reported to have BP-lowering effect in addition to blood glucose-lowering effect, however, its mechanism is still unknown. This study aimed to investigate the mechanism of blood pressure (BP) lowering effects of SGLT2 inhibitors using 24-h urinary collection in obese type 2 diabetes patients. Methods Twenty patients with type 2 diabetes (age 48.2 ± 10.7 years, BMI 33.0 ± 4.9 kg/m2) were enrolled. Urine volume, 24-h urinary glucose and sodium excretion, and BP at baseline and 2 weeks and 6 months after administration were measured. Body weight, glycosylated hemoglobin, and BP were evaluated before and 1, 3, and 6 months after SGLT2 inhibitor administration. We evaluated the changes in urine volume and urinary excretion of glucose and sodium as well as correlations among urine volume and urinary sodium glucose excretion at 2 weeks and 6 months after administration of the SGLT2 inhibitors. Furthermore, we investigated the correlations between changes in BP and urinary excretion of sodium and glucose at the same time. Results Two weeks after administration, systolic BP (SBP) significantly decreased (128.5 ± 11.0 to 123.2 ± 9.8 mmHg, P = 0.0314), but diastolic BP (DBP) did not (74.4 ± 10.4 to 73.4 ± 8.5 mmHg, P = 0.5821). The decreased SBP significantly correlated with increased urinary glucose excretion (R = −0.62, P = 0.0073), but not increased urinary sodium excretion. At 6 months, SBP (118.6 ± 11.0 mmHg, P = 0.0041) and DBP (68.4 mmHg, P = 0.0363) significantly decreased. The decreased SBP significantly correlated with increased urinary sodium excretion (R = −0.60, P = 0.0014), but not increased urinary glucose excretion. Conclusions SGLT2 inhibitors significantly decreased SBP after 1 month and DBP after 6 months in obese patients with type 2 diabetes. The main mechanism of the BP-lowering effect may be plasma volume reduction by osmotic diuresis at 2 weeks and by natriuresis at 6 months after SGLT2 inhibitor administration.
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Affiliation(s)
- Shin Kawasoe
- Department of Cardiovascular Medicine and Hypertension, Graduate School of Medical and Dental Sciences, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima, 890-8520, Japan
| | | | | | | | - Masaaki Miyata
- Department of Cardiovascular Medicine and Hypertension, Graduate School of Medical and Dental Sciences, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima, 890-8520, Japan.
| | - Mariko Kawasoe
- Department of Cardiovascular Medicine and Hypertension, Graduate School of Medical and Dental Sciences, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima, 890-8520, Japan
| | - Takuro Kubozono
- Department of Cardiovascular Medicine and Hypertension, Graduate School of Medical and Dental Sciences, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima, 890-8520, Japan
| | - Mitsuru Ohishi
- Department of Cardiovascular Medicine and Hypertension, Graduate School of Medical and Dental Sciences, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima, 890-8520, Japan
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10
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Zhao X, Cui L, Lang Y, Liu T, Lu J, Wang C, Tuffery-Giraud S, Bottillo I, Wang X, Shao L. A recurrent deletion in the SLC5A2 gene including the intron 7 branch site responsible for familial renal glucosuria. Sci Rep 2016; 6:33920. [PMID: 27666404 PMCID: PMC5036194 DOI: 10.1038/srep33920] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 09/06/2016] [Indexed: 12/31/2022] Open
Abstract
Familial renal glycosuria (FRG) is caused by mutations in the SLC5A2 gene, which codes for Na+-glucose co-transporters 2 (SGLT2). The aim of this study was to analyze and identify the mutations in 16 patients from 8 families with FRG. All coding regions, including intron-exon boundaries, were analyzed using PCR followed by direct sequence analysis. Six mutations in SLC5A2 gene were identified, including five missense mutations (c.393G > C, p.K131N; c.1003A > G, p.S335G; c.1343A > G, p.Q448R; c.1420G > C, p.A474P; c.1739G > A, p.G580D) and a 22-bp deletion in intron 7 (c.886(-10_-31)del) removing the putative branch point sequence. By the minigene studies using the pSPL3 plasmids, we confirmed that the deletion c.886(-10_-31)del acts as a splicing mutation. Furthermore, we found that this deletion causes exclusion of exon 8 in the SCL5A2 transcript in patients. The mutation c.886(-10_-31)del was present in 5 (62.5%) of 8 families, and accounts for about 37.5% of the total alleles (6/16). In conclusion, six mutations resulting in FRG were found, and the c.886(-10_-31)del may be the high frequency mutation that can be screened in FRG patients with uniallelic or negative SLC5A2 mutations.
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Affiliation(s)
- Xiangzhong Zhao
- Central Laboratory, The Affiliated Hospital of Qingdao University, 1677 Wutaishan Road, Qingdao 266555, China
| | - Li Cui
- Department of Nephrology, the Affiliated Hospital of Qingdao University, 16 Jiangsu Road, Qingdao 266003, China
| | - Yanhua Lang
- Department of Nephrology, the Affiliated Hospital of Qingdao University, 16 Jiangsu Road, Qingdao 266003, China
| | - Ting Liu
- Central Laboratory, The Affiliated Hospital of Qingdao University, 1677 Wutaishan Road, Qingdao 266555, China.,Department of Nephrology, the Affiliated Hospital of Qingdao University, 16 Jiangsu Road, Qingdao 266003, China
| | - Jingru Lu
- Central Laboratory, The Affiliated Hospital of Qingdao University, 1677 Wutaishan Road, Qingdao 266555, China.,Department of Nephrology, the Affiliated Hospital of Qingdao University, 16 Jiangsu Road, Qingdao 266003, China
| | - Cui Wang
- Central Laboratory, The Affiliated Hospital of Qingdao University, 1677 Wutaishan Road, Qingdao 266555, China.,Department of Nephrology, the Affiliated Hospital of Qingdao University, 16 Jiangsu Road, Qingdao 266003, China
| | - Sylvie Tuffery-Giraud
- Laboratory of Genetics of Rare Diseases, EA7402, University of Montpellier, F-34000, France
| | - Irene Bottillo
- Division of Medical Genetics, Department of Molecular Medicine, Sapienza University, San Camillo-Forlanini Hospital, Circ. Gianicolense, 87, Padiglione Morgagni 00152, Rome, Italy
| | - Xinsheng Wang
- Urology, Affiliated Hospital, Qingdao University, Qingdao 266003, China
| | - Leping Shao
- Central Laboratory, The Affiliated Hospital of Qingdao University, 1677 Wutaishan Road, Qingdao 266555, China.,Department of Nephrology, the Affiliated Hospital of Qingdao University, 16 Jiangsu Road, Qingdao 266003, China
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11
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Yu L, Hou P, Liu GP, Zhang H. Novel SLC5A2 mutation contributes to familial renal glucosuria: Abnormal expression in renal tissues. Exp Ther Med 2016; 12:649-652. [PMID: 27446256 PMCID: PMC4950299 DOI: 10.3892/etm.2016.3388] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Accepted: 04/27/2016] [Indexed: 12/18/2022] Open
Abstract
Familial renal glucosuria (FRG) is characterized by persistent glucosuria in the presence of normal serum glucose concentrations, while other impairments of tubular function are absent. Mutations in the sodium-glucose co-transporter 2 (SLC5A2) gene have been found to be responsible for FRG. However, direct evidence for the presence of SLC5A2 mutant in renal tissues is very rare. In previous studies, a non-sense mutation (c.1320 G>A:p.W440X) that would cause premature termination of the protein was found. However, the effects in the renal tissues were not reported. In the current study, a patient with FRG and a urinary glucose excretion rate of 8.3 g/day is described, for whom a novel missense mutation (c.1319G>A:p.W440X) was revealed by sequencing. Furthermore, in the immunofluorescence examination of a renal biopsy specimen, SLC5A2 was detected in the apical side of the proximal convoluted tubule, discontinuously decreased in comparison with that in normal and disease controls. The results imply that both wild-type SLC5A2 and mutant SLC5A2 with abnormal distribution were expressed in the renal tissues, and that the reduction of SLC5A2 expression and function were due to the c.1319G>A:p.W440X mutation. The current study provides valuable clues regarding the SLC5A2 molecule from genotype to phenotype in families affected by FRG.
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Affiliation(s)
- Lei Yu
- Renal Division, Inner Mongolia People's Hospital, Hohhot, Inner Mongolia 010017, P.R. China
| | - Ping Hou
- Renal Division, Peking University First Hospital, Peking University Institute of Nephrology, Key Laboratory of Renal Disease, Ministry of Health of China, Beijing 100034, P.R. China
| | - Guo-Ping Liu
- Renal Division, Inner Mongolia People's Hospital, Hohhot, Inner Mongolia 010017, P.R. China
| | - Hong Zhang
- Renal Division, Peking University First Hospital, Peking University Institute of Nephrology, Key Laboratory of Renal Disease, Ministry of Health of China, Beijing 100034, P.R. China
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Yu L, Xu Q, Hou P, Zhang H. Decreased expression and function of sodium-glucose co-transporter 2 from a novel C-terminal mutation: a case report. BMC Nephrol 2016; 17:31. [PMID: 27000029 PMCID: PMC4800764 DOI: 10.1186/s12882-016-0244-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 03/17/2016] [Indexed: 12/03/2022] Open
Abstract
Background Familial renal glucosuria (FRG) is characterized by persistent glucosuria in the presence of normal serum glucose concentrations, and the absence of other impairments of tubular function. Mutations in the sodium–glucose co-transporter 2 (SGLT2) gene (SLC5A2) are causative of FRG the long-term outcome of which is well know. In the search for potential new drug targets for SGLT2 inhibitors with which to treat the diabetes, expressional and functional studies of SGLT2 have been the focus of attention, but reports of these are rare. Furthermore, it is well known that the alleles in the C-terminal are very important for the expression and function in some genes. However, little is known about the effect of mutation in SLC5A2 C- terminal. Case presentation Here, we identified a FRG patient with urine glucose excretion 7.56 g/day and a novel SLC5A2 missense mutation, c.1891G > A/p.(E631K), by DNA sequencing. Expression and function of the mutant SGLT2 (631 K) fused to green fluorescent protein (GFP) were verified by western blotting, confocal laser microscopy, and transport activity assays in cultured HEK293 cells. Although wild-type SGLT2–GFP and 631 K mutant–GFP fusion proteins were properly expressed in a punctate pattern in the cell membrane, and co-localized with the cell membrane marker DiIC18(3), the expression of the mutant fusion protein was obviously decreased (24 %). Moreover, the uptake activity of the mutant SGLT2 631 K–GFP fusion protein was significantly decreased compared with wild-type (3629 ± 1082 vs. 7926 ± 1153, P < 0.001). Conclusion These results suggest that the SLC5A2 C-terminal is very important for protein expression. We speculate that the observed reduced expression of the mutant transporter led to a decrease in transport of the glucose analog 2-(N-(7-nitrobenz-2-oxa-1,3- diazol-4-yl)amino)-2-deoxyglucose. The current study provides a starting point for further investigations of the SGLT2 molecular mechanism in FRG families, and offers functional insights into the development of anti-diabetes drugs.
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Affiliation(s)
- Lei Yu
- Renal Division, Inner Mongolia People's Hospital, Hohhot, 010017, P.R. China.
| | - Qiaozhi Xu
- Computer & Information Engineering College, Inner Mongolia Normal University, Hohhot, 010022, China
| | - Ping Hou
- Renal Division, Peking University First Hospital, Peking University Institute of Nephrology, Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, 100034, China
| | - Hong Zhang
- Renal Division, Peking University First Hospital, Peking University Institute of Nephrology, Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, 100034, China
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