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Abstract
Sequential expression of claudins, a family of tight junction proteins, along the nephron mirrors the sequential expression of ion channels and transporters. Only by the interplay of transcellular and paracellular transport can the kidney efficiently maintain electrolyte and water homeostasis in an organism. Although channel and transporter defects have long been known to perturb homeostasis, the contribution of individual tight junction proteins has been less clear. Over the past two decades, the regulation and dysregulation of claudins have been intensively studied in the gastrointestinal tract. Claudin expression patterns have, for instance, been found to be affected in infection and inflammation, or in cancer. In the kidney, a deeper understanding of the causes as well as the effects of claudin expression alterations is only just emerging. Little is known about hormonal control of the paracellular pathway along the nephron, effects of cytokines on renal claudin expression or relevance of changes in paracellular permeability to the outcome in any of the major kidney diseases. By summarizing current findings on the role of specific claudins in maintaining electrolyte and water homeostasis, this Review aims to stimulate investigations on claudins as prognostic markers or as druggable targets in kidney disease.
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Affiliation(s)
- Luca Meoli
- Clinical Physiology/Nutritional Medicine, Medical Department, Division of Gastroenterology, Infectiology, Rheumatology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Dorothee Günzel
- Clinical Physiology/Nutritional Medicine, Medical Department, Division of Gastroenterology, Infectiology, Rheumatology, Charité - Universitätsmedizin Berlin, Berlin, Germany.
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Sait B, Chidambaram AC, Vidhyasagar K, Dinesh Babu RM, Sagayaraj B. Nephrocalcinosis in a 3-year-old child with hypocalcemia: Answers. Pediatr Nephrol 2023; 38:2565-2569. [PMID: 35925425 DOI: 10.1007/s00467-022-05695-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 07/02/2022] [Accepted: 07/04/2022] [Indexed: 11/25/2022]
Affiliation(s)
- Benazer Sait
- Department of Pediatrics, Saveetha Institute of Medical and Technical Sciences, Chennai, 600056, India
| | | | | | - R M Dinesh Babu
- Department of Pediatrics, Saveetha Institute of Medical and Technical Sciences, Chennai, 600056, India
| | - Benjamin Sagayaraj
- Department of Pediatrics, Saveetha Institute of Medical and Technical Sciences, Chennai, 600056, India
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3
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The advances of calcium oxalate calculi associated drugs and targets. Eur J Pharmacol 2022; 935:175324. [DOI: 10.1016/j.ejphar.2022.175324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 09/23/2022] [Accepted: 10/11/2022] [Indexed: 11/20/2022]
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Molecular mechanisms altering tubular calcium reabsorption. Pediatr Nephrol 2022; 37:707-718. [PMID: 33796889 DOI: 10.1007/s00467-021-05049-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 02/12/2021] [Accepted: 03/09/2021] [Indexed: 12/09/2022]
Abstract
The majority of calcium filtered by the glomerulus is reabsorbed along the nephron. Most is reabsorbed from the proximal tubule (> 60%) via a paracellular pathway composed of the tight junction proteins claudins-2 and -12, a process driven by sodium and consequently water reabsorption. The thick ascending limb reabsorbs the next greatest amount of calcium (20-25%), also by a paracellular pathway composed of claudins-16 and -19. This pathway is regulated by the CaSR, whose activity increases the expression of claudin-14, a protein that blocks paracellular calcium reabsorption. The fine tuning of urinary calcium excretion occurs in the distal convoluted and connecting tubule by a transcellular pathway composed of the apical calcium channel TRPV5, the calcium shuttling protein calbindin-D28K and the basolateral proteins PMCA1b and the sodium calcium exchanger, NCX. Not surprisingly, mutations in a subset of these genes cause monogenic disorders with hypercalciuria as a part of the phenotype. More commonly, "idiopathic" hypercalciuria is encountered clinically with genetic variations in CLDN14, the CASR and TRPV5 associating with kidney stones and increased urinary calcium excretion. An understanding of the molecular pathways conferring kidney tubular calcium reabsorption is employed in this review to help explain how dietary and medical interventions for this disorder lower urinary calcium excretion.
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Jo CH, Kim S, Kim GH. Claudins in kidney health and disease. Kidney Res Clin Pract 2022; 41:275-287. [PMID: 35354245 PMCID: PMC9184838 DOI: 10.23876/j.krcp.21.279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 12/29/2021] [Indexed: 11/04/2022] Open
Abstract
Claudins are strategically located to exert their physiologic actions along with the nephron segments from the glomerulus. Claudin-1 is normally located in the Bowman’s capsule, but its overexpression can reach the podocytes and lead to albuminuria. In the proximal tubule (PT), claudin-2 forms paracellular channels selective for water, Na+, K+, and Ca2+. Claudin-2 gene mutations are associated with hypercalciuria and kidney stones. Claudin-10 has two splice variants, -10a and -10b; Claudin-10a acts as an anion-selective channel in the PT, and claudin-10b functions as a cation-selective pore in the thick ascending limb (TAL). Claudin-16 and claudin-19 mediate paracellular transport of Na+, Ca2+, and Mg2+ in the TAL, where the expression of claudin-3/16/19 and claudin-10b are mutually exclusive. The claudin-16 or -19 mutation causes familial hypomagnesemia with hypercalciuria and nephrocalcinosis. Claudin-14 polymorphisms have been linked to increased risk of hypercalciuria. Claudin-10b mutations produce HELIX syndrome, which encompasses hypohidrosis, electrolyte imbalance, lacrimal gland dysfunction, ichthyosis, and xerostomia. Hypercalciuria and magnesuria in metabolic acidosis are related to downregulation of PT and TAL claudins. In the TAL, stimulation of calcium-sensing receptors upregulates claudin-14 and negatively acts on the claudin-16/19 complex. Claudin-3 acts as a general barrier to ions in the collecting duct. If this barrier is disturbed, urine acidification might be impaired. Claudin-7 forms a nonselective paracellular channel facilitating Cl– and Na+ reabsorption in the collecting ducts. Claudin-4 and -8 serve as anion channels and mediate paracellular Cl– transport; their upregulation may contribute to pseudohypoaldosteronism II and salt-sensitive hypertension.
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Affiliation(s)
- Chor ho Jo
- Hanyang Biomedical Research Institute, Hanyang University College of Medicine, Seoul, Republic of Korea
| | - Sua Kim
- Hanyang Biomedical Research Institute, Hanyang University College of Medicine, Seoul, Republic of Korea
| | - Gheun-Ho Kim
- Hanyang Biomedical Research Institute, Hanyang University College of Medicine, Seoul, Republic of Korea
- Department of Internal Medicine, Hanyang University College of Medicine, Seoul, Republic of Korea
- Correspondence: Gheun-Ho Kim Department of Internal Medicine, Hanyang University College of Medicine, 222-1 Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea. E-mail:
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Ullah I, Murtaza K, Ammara H, Misbah, Bhinder MA, Riaz A, Shehzad W, Zahoor MY. Association study of CLDN14 variations in patients with kidney stones. Open Life Sci 2022; 17:81-92. [PMID: 35291565 PMCID: PMC8886595 DOI: 10.1515/biol-2021-0134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 10/08/2021] [Accepted: 10/10/2021] [Indexed: 11/28/2022] Open
Abstract
Claudin-14 protein plays an essential role in regulating calcium ions in the kidney and ear. Two phenotypes, hearing loss and kidney stones, were reportedly associated with variations in the CLDN14 gene. This study aimed to understand CLDN14 mutations’ contribution to hearing loss and renal stone formation in a Pakistani cohort. We analyzed CLDN14 sequence variations in 100 patients, along with healthy individuals, to assess whether specific polymorphisms were associated with the disease. Also, we performed an in silico analysis using a mutation database and protein annotation. The rs219779’s genotype CT (p = 0.0020) and rs219780’s genotype AG (p = 0.0012) were significantly associated with kidney stones. We also found that a novel haplotype, “TA” associated with kidney stone formation, has moderate linkage disequilibrium. The TA haplotype was significantly correlated with a kidney stone risk formation of 3.76-fold (OR (CI 95%) = 3.76 (1.83–7.72)) and p = 0.0016 compared to other haplotypes. In silico analysis revealed that mutations associated with hearing loss were not correlated with renal stone formation but affected claudin-14 protein stability. We structurally mapped a novel TA haplotype of CLDN14 that, based on our analysis, likely contributes to the pathogenesis of renal stones.
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Affiliation(s)
- Ihsan Ullah
- Molecular Biology and Biotechnology Section, Institute of Biochemistry & Biotechnology, University of Veterinary & Animal Sciences , Syed Abdul Qadir Jillani (Out Fall) Road , Lahore 54000 , Pakistan
| | - Khadijah Murtaza
- Molecular Biology and Biotechnology Section, Institute of Biochemistry & Biotechnology, University of Veterinary & Animal Sciences , Syed Abdul Qadir Jillani (Out Fall) Road , Lahore 54000 , Pakistan
| | - Hafiza Ammara
- Molecular Biology and Biotechnology Section, Institute of Biochemistry & Biotechnology, University of Veterinary & Animal Sciences , Syed Abdul Qadir Jillani (Out Fall) Road , Lahore 54000 , Pakistan
| | - Misbah
- Department of Medicine, Services Hospital , Lahore 54000 , Pakistan
| | - Munir Ahmad Bhinder
- Department of Human Genetics and Molecular Biology, University of Health Sciences , Lahore 54000 , Pakistan
| | - Amjad Riaz
- Department of Theriogenology, University of Veterinary & Animal Sciences , Lahore 54000 , Pakistan
| | - Wasim Shehzad
- Molecular Biology and Biotechnology Section, Institute of Biochemistry & Biotechnology, University of Veterinary & Animal Sciences , Syed Abdul Qadir Jillani (Out Fall) Road , Lahore 54000 , Pakistan
| | - Muhammad Yasir Zahoor
- Molecular Biology and Biotechnology Section, Institute of Biochemistry & Biotechnology, University of Veterinary & Animal Sciences , Syed Abdul Qadir Jillani (Out Fall) Road , Lahore 54000 , Pakistan
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Negri AL, Del Valle EE. Role of claudins in idiopathic hypercalciuria and renal lithiasis. Int Urol Nephrol 2022; 54:2197-2204. [PMID: 35084652 DOI: 10.1007/s11255-022-03119-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 01/11/2022] [Indexed: 11/25/2022]
Abstract
Paracellular transport in the kidney is mediated by a family of proteins located in the tight junctions called claudins which confers its ionic selectivity. Claudin-2 is highly expressed in the proximal tubule and descending limb of Henle and mediate paracellular reabsorption of sodium and calcium cations. In the thick ascending limb of Henle (TALH) calcium is reabsorbed by a paracellular channel formed by Claudin-16 and-19. Claudin-16 mediates cationic permeability while Claudin-19 increases the cationic selectivity of Claudin-16 by blocking anionic permeability. On the other hand, Claudin 14, that is also located in TALH, inhibits the paracellular permeability of Claudin-16 to calcium. Recent wide genomic association analysis studies have detected four common synonymous variants (genetic polymorphisms of a single nucleotide, SNPs) at the locus of Claudin-14 gene that were significantly associated with the presence of renal lithiasis. Another study of wide genomic association and nephrolithiasis was carried out in the general population but including chromosome X, where claudin-2 gene is located. They detected nine SNPs that had a significant association with renal lithiasis risk. A greater knowledge of the paracellular pathway controlled by claudins and its regulation will allow us to develop future new treatments for idiopathic hypercalciuria and renal lithiasis.
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Affiliation(s)
- Armando Luis Negri
- Institute for Metabolic Research, Faculty of Medicine, Del Salvador University, Libertad 836, 1 Floor, 1012, Buenos Aires, Argentina.
| | - Elisa Elena Del Valle
- Institute for Metabolic Research, Faculty of Medicine, Del Salvador University, Libertad 836, 1 Floor, 1012, Buenos Aires, Argentina
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da Silva Lopes K, Abe SK. Polymorphisms Contributing to Calcium Status: A Systematic Review. Nutrients 2021; 13:2488. [PMID: 34444650 PMCID: PMC8398213 DOI: 10.3390/nu13082488] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 07/08/2021] [Accepted: 07/17/2021] [Indexed: 01/28/2023] Open
Abstract
This systematic review assessed genotypes and changes in calcium homeostasis. A literature search was performed in EMBASE, Medline and CENTRAL on 7 August 2020 identifying 1012 references. Studies were included with any human population related to the topic of interest, and genetic variations in genes related to calcium metabolism were considered. Two reviewers independently screened references, extracted relevant data and assessed study quality using the Q-Genie tool. Forty-one studies investigating Single Nucleotide Polymorphisms (SNPs) in relation to calcium status were identified. Almost half of the included studies were of good study quality according to the Q-Genie tool. Seventeen studies were cross-sectional, 14 case-control, seven association and three were Mendelian randomization studies. Included studies were conducted in over 18 countries. Participants were mainly adults, while six studies included children and adolescents. Ethnicity was described in 31 studies and half of these included Caucasian participants. Twenty-six independent studies examined the association between calcium and polymorphism in the calcium-sensing receptor (CASR) gene. Five studies assessed the association between polymorphisms of the Vitamin D receptor (VDR) gene and changes in calcium levels or renal excretion. The remaining ten studies investigated calcium homeostasis and other gene polymorphisms such as the CYP24A1 SNP or CLDN14. This study identified several CASR, VDR and other gene SNPs associated with calcium status. However, to provide evidence to guide dietary recommendations, further research is needed to explore the association between common polymorphisms and calcium requirements.
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Affiliation(s)
| | - Sarah Krull Abe
- Center for Public Health Sciences, National Cancer Center, Division of Prevention, Tokyo 104-0045, Japan
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Runova GE, Golounina OO, Glinkina IV, Sych YP, Fadeev VV. [Differential diagnosis of normocalcemic hyperparathyroidism and idiopathic hypercalciuria on the example of clinical case]. PROBLEMY ENDOKRINOLOGII 2020; 66:13-17. [PMID: 33481363 DOI: 10.14341/probl12677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 12/10/2020] [Accepted: 12/16/2020] [Indexed: 06/12/2023]
Abstract
Idiopathic hypercalciuria is a heterogeneous generalized disorder caused by various defects in calcium transport and increased urinary calcium excretion. The main etiopathogenetic factors are violations of vitamin D metabolism, changes in the sensitivity of calcitriol receptors and violations of the processes of calcium reabsorption in the proximal tubules and in the ascending knee of the Henle loop. This article presents a clinical observation of patient with idiopathic hypercalciuria, initially high levels of parathyroid hormone (PTH) in the absence of hyperparathyroidism. Therapy with thiazide diuretics allowed to achieve normalization of daily urinary calcium excretion and reducing PTH. Despite the low prevalence of idiopathic hypercalciuria, differential diagnosis of this metabolic disorder should be carried out with mandatory consideration of clinical and laboratory data, as well as with diseases that may cause increased PTH production.
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Affiliation(s)
- G E Runova
- I.M. Sechenov First Moscow State Medical University (Sechenov University)
| | - O O Golounina
- I.M. Sechenov First Moscow State Medical University (Sechenov University)
| | - I V Glinkina
- I.M. Sechenov First Moscow State Medical University (Sechenov University)
| | - Yu P Sych
- I.M. Sechenov First Moscow State Medical University (Sechenov University)
| | - V V Fadeev
- I.M. Sechenov First Moscow State Medical University (Sechenov University)
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Prot-Bertoye C, Houillier P. Claudins in Renal Physiology and Pathology. Genes (Basel) 2020; 11:genes11030290. [PMID: 32164158 PMCID: PMC7140793 DOI: 10.3390/genes11030290] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 02/24/2020] [Accepted: 02/24/2020] [Indexed: 12/18/2022] Open
Abstract
Claudins are integral proteins expressed at the tight junctions of epithelial and endothelial cells. In the mammalian kidney, every tubular segment express a specific set of claudins that give to that segment unique properties regarding permeability and selectivity of the paracellular pathway. So far, 3 claudins (10b, 16 and 19) have been causally traced to rare human syndromes: variants of CLDN10b cause HELIX syndrome and variants of CLDN16 or CLDN19 cause familial hypomagnesemia with hypercalciuria and nephrocalcinosis. The review summarizes our current knowledge on the physiology of mammalian tight junctions and paracellular ion transport, as well as on the role of the 3 above-mentioned claudins in health and disease. Claudin 14, although not having been causally linked to any rare renal disease, is also considered, because available evidence suggests that it may interact with claudin 16. Some single-nucleotide polymorphisms of CLDN14 are associated with urinary calcium excretion and/or kidney stones. For each claudin considered, the pattern of expression, the function and the human syndrome caused by pathogenic variants are described.
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Affiliation(s)
- Caroline Prot-Bertoye
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université de Paris, F-75006 Paris, France;
- Service de Physiologie, Hôpital Européen Georges Pompidou, Assistance Publique-Hôpitaux de Paris, F-75015 Paris, France
- Centre de Référence des Maladies Rénales Héréditaires de l’Enfant et de l’Adulte (MARHEA), F-75015 Paris, France
- Centre de Référence des Maladies Rares du Calcium et du Phosphate, F-75015 Paris, France
- CNRS, ERL8228, F-75006 Paris, France
| | - Pascal Houillier
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université de Paris, F-75006 Paris, France;
- Service de Physiologie, Hôpital Européen Georges Pompidou, Assistance Publique-Hôpitaux de Paris, F-75015 Paris, France
- Centre de Référence des Maladies Rénales Héréditaires de l’Enfant et de l’Adulte (MARHEA), F-75015 Paris, France
- Centre de Référence des Maladies Rares du Calcium et du Phosphate, F-75015 Paris, France
- CNRS, ERL8228, F-75006 Paris, France
- Correspondence:
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Citterio L, Delli Carpini S, Lupoli S, Brioni E, Simonini M, Fontana S, Zagato L, Messaggio E, Barlassina C, Cusi D, Manunta P, Lanzani C. Klotho Gene in Human Salt-Sensitive Hypertension. Clin J Am Soc Nephrol 2020; 15:375-383. [PMID: 31992575 PMCID: PMC7057312 DOI: 10.2215/cjn.08620719] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 12/23/2019] [Indexed: 12/11/2022]
Abstract
BACKGROUND AND OBJECTIVES Hypertension is a common aging-related disorder. Salt intake is one of the main environmental factors contributing to the development of hypertension. Transgenic mice with one-half Klotho deficiency displayed a spontaneous BP increase and salt-sensitive hypertension in response to high sodium intake. Usually circulating levels of α-Klotho decrease with age, and this reduction may be stronger in patients with several aging-related diseases. This study aimed at exploring the association of Klotho with salt sensitivity in humans. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS The role of Klotho polymorphisms and α-Klotho serum levels was evaluated in patients with hypertension who were treatment naive and underwent an acute salt-sensitivity test (discovery n=673, intravenous 2 L of 0.9% saline in 2 hours). Salt sensitivity was defined as a mean BP increase of >4 mm Hg at the end of the infusion. A total of 32 single nucleotide polymorphisms in the Klotho gene (KL), previously identified with a genome-wide association study, were used in the genetic analysis and studied for a pressure-natriuresis relationship. RESULTS Of the patients with hypertension, 35% were classified as salt sensitive. The most relevant polymorphism associated with pressure natriuresis was the common missense single nucleotide polymorphism rs9536314, and the GG and GT genotypes were more represented among patients who were salt sensitive (P=0.001). Those carrying the G allele showed a less steep pressure-natriuresis relationship, meaning that a significant increase in mean BP was needed to excrete the same quantity of salt compared with patients who were salt resistant. KL rs9536314 also replicated the pressure-natriuresis association in an independent replication cohort (n=193) and in the combined analysis (n=866). There was an inverse relationship between circulating Klotho and mean BP changes after the saline infusion (r=-0.14, P=0.03). Moreover, circulating α-Klotho was directly related to kidney function at baseline eGFR (r=0.22, P<0.001). CONCLUSIONS KL rs9536314 is associated with salt-sensitive hypertension in patients with hypertension who are treatment naive. Moreover, circulating α-Klotho levels were mainly related to diastolic BP changes at the end of a salt load and to eGFR as an expression of kidney aging.
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Affiliation(s)
- Lorena Citterio
- Genomics of Renal Diseases and Hypertension Unit, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy
| | - Simona Delli Carpini
- Genomics of Renal Diseases and Hypertension Unit, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy
| | - Sara Lupoli
- Department of Health Sciences, University of Milan, Filarete Foundation, Milan, Italy
| | - Elena Brioni
- Genomics of Renal Diseases and Hypertension Unit, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy
| | - Marco Simonini
- Genomics of Renal Diseases and Hypertension Unit, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy
| | - Simone Fontana
- Genomics of Renal Diseases and Hypertension Unit, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy
| | - Laura Zagato
- Genomics of Renal Diseases and Hypertension Unit, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy
| | - Elisabetta Messaggio
- Genomics of Renal Diseases and Hypertension Unit, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy
| | - Cristina Barlassina
- Department of Health Sciences, University of Milan, Filarete Foundation, Milan, Italy
| | - Daniele Cusi
- Institute of Biomedical Technologies, National Research Council of Italy (Consiglio Nazionale delle Ricerche, CNR), Milan, Italy; and
- Bio4Dreams Scientific Unit, Bio4Dreams—Business Nursery for Life Sciences, Milan, Italy
| | - Paolo Manunta
- Genomics of Renal Diseases and Hypertension Unit, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy
| | - Chiara Lanzani
- Genomics of Renal Diseases and Hypertension Unit, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy
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12
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Iancu D, Ashton E. Inherited Renal Tubulopathies-Challenges and Controversies. Genes (Basel) 2020; 11:genes11030277. [PMID: 32150856 PMCID: PMC7140864 DOI: 10.3390/genes11030277] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 02/29/2020] [Accepted: 02/29/2020] [Indexed: 12/23/2022] Open
Abstract
Electrolyte homeostasis is maintained by the kidney through a complex transport function mostly performed by specialized proteins distributed along the renal tubules. Pathogenic variants in the genes encoding these proteins impair this function and have consequences on the whole organism. Establishing a genetic diagnosis in patients with renal tubular dysfunction is a challenging task given the genetic and phenotypic heterogeneity, functional characteristics of the genes involved and the number of yet unknown causes. Part of these difficulties can be overcome by gathering large patient cohorts and applying high-throughput sequencing techniques combined with experimental work to prove functional impact. This approach has led to the identification of a number of genes but also generated controversies about proper interpretation of variants. In this article, we will highlight these challenges and controversies.
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Affiliation(s)
- Daniela Iancu
- UCL-Centre for Nephrology, Royal Free Campus, University College London, Rowland Hill Street, London NW3 2PF, UK
- Correspondence: ; Tel.: +44-2381204172; Fax: +44-020-74726476
| | - Emma Ashton
- Rare & Inherited Disease Laboratory, London North Genomic Laboratory Hub, Great Ormond Street Hospital for Children National Health Service Foundation Trust, Levels 4-6 Barclay House 37, Queen Square, London WC1N 3BH, UK;
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Palsson R, Indridason OS, Edvardsson VO, Oddsson A. Genetics of common complex kidney stone disease: insights from genome-wide association studies. Urolithiasis 2018; 47:11-21. [PMID: 30523390 DOI: 10.1007/s00240-018-1094-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 11/08/2018] [Indexed: 12/29/2022]
Abstract
Kidney stone disease is a common disorder in Western countries that is associated with significant suffering, morbidity, and cost for the healthcare system. Numerous studies have demonstrated familial aggregation of nephrolithiasis and a twin study estimated the heritability to be 56%. Over the past decade, genome-wide association studies have uncovered several sequence variants that confer increased risk of common complex kidney stone disease. The first reported variants were observed at the CLDN14 locus in the Icelandic population. This finding has since been replicated in other populations. The CLDN14 gene is expressed in tight junctions of the thick ascending limb of the loop of Henle, where the protein is believed to play a role in regulation of calcium transport. More recent studies have uncovered variants at the ALPL, SLC34A1, CASR, and TRPV5 loci, the first two genes playing a role in renal handling of phosphate, while the latter two are involved in calcium homeostasis. Although genetic data have provided insights into the molecular basis of kidney stone disease, much remains to be learned about the contribution of genetic factors to stone formation. Nevertheless, the progress made in recent years indicates that exciting times lie ahead in genetic research on kidney stone disease.
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Affiliation(s)
- Runolfur Palsson
- Faculty of Medicine, School of Health Sciences, University of Iceland, Reykjavik, Iceland. .,Division of Nephrology, Internal Medicine Services, Landspitali-The National University Hospital of Iceland, Reykjavik, Iceland.
| | - Olafur S Indridason
- Division of Nephrology, Internal Medicine Services, Landspitali-The National University Hospital of Iceland, Reykjavik, Iceland
| | - Vidar O Edvardsson
- Faculty of Medicine, School of Health Sciences, University of Iceland, Reykjavik, Iceland.,Children's Medical Center, Landspitali-The National University Hospital of Iceland, Reykjavik, Iceland
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Shah RJ, Lieske JC. Inching toward a Greater Understanding of Genetic Hypercalciuria: The Role of Claudins. Clin J Am Soc Nephrol 2018; 13:1460-1462. [PMID: 30232135 PMCID: PMC6218823 DOI: 10.2215/cjn.10030818] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Ronak Jagdeep Shah
- Division of Nephrology and Hypertension, Mayo Clinic College of Medicine, Rochester, Minnesota
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