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Gefen AM, Zaritsky JJ. Review of childhood genetic nephrolithiasis and nephrocalcinosis. Front Genet 2024; 15:1381174. [PMID: 38606357 PMCID: PMC11007102 DOI: 10.3389/fgene.2024.1381174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2024] [Accepted: 03/04/2024] [Indexed: 04/13/2024] Open
Abstract
Nephrolithiasis (NL) is a common condition worldwide. The incidence of NL and nephrocalcinosis (NC) has been increasing, along with their associated morbidity and economic burden. The etiology of NL and NC is multifactorial and includes both environmental components and genetic components, with multiple studies showing high heritability. Causative gene variants have been detected in up to 32% of children with NL and NC. Children with NL and NC are genotypically heterogenous, but often phenotypically relatively homogenous, and there are subsequently little data on the predictors of genetic childhood NL and NC. Most genetic diseases associated with NL and NC are secondary to hypercalciuria, including those secondary to hypercalcemia, renal phosphate wasting, renal magnesium wasting, distal renal tubular acidosis (RTA), proximal tubulopathies, mixed or variable tubulopathies, Bartter syndrome, hyperaldosteronism and pseudohyperaldosteronism, and hyperparathyroidism and hypoparathyroidism. The remaining minority of genetic diseases associated with NL and NC are secondary to hyperoxaluria, cystinuria, hyperuricosuria, xanthinuria, other metabolic disorders, and multifactorial etiologies. Genome-wide association studies (GWAS) in adults have identified multiple polygenic traits associated with NL and NC, often involving genes that are involved in calcium, phosphorus, magnesium, and vitamin D homeostasis. Compared to adults, there is a relative paucity of studies in children with NL and NC. This review aims to focus on the genetic component of NL and NC in children.
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Affiliation(s)
- Ashley M. Gefen
- Phoenix Children’s Hospital, Department of Pediatrics, Division of Nephrology, Phoenix, AZ, United States
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2
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Yang G, Mack H, Harraka P, Colville D, Savige J. Ocular manifestations of the genetic renal tubulopathies. Ophthalmic Genet 2023; 44:515-529. [PMID: 37702059 DOI: 10.1080/13816810.2023.2253901] [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: 04/06/2023] [Accepted: 08/26/2023] [Indexed: 09/14/2023]
Abstract
BACKGROUND The genetic tubulopathies are rare and heterogenous disorders that are often difficult to identify. This study examined the tubulopathy-causing genes for ocular associations that suggested their genetic basis and, in some cases, the affected gene. METHODS Sixty-seven genes from the Genomics England renal tubulopathy panel were reviewed for ocular features, and for retinal expression in the Human Protein Atlas and an ocular phenotype in mouse models in the Mouse Genome Informatics database. The genes resulted in disease affecting the proximal tubules (n = 24); the thick ascending limb of the loop of Henle (n = 10); the distal convoluted tubule (n = 15); or the collecting duct (n = 18). RESULTS Twenty-five of the tubulopathy-associated genes (37%) had ocular features reported in human disease, 49 (73%) were expressed in the retina, although often at low levels, and 16 (24%) of the corresponding mouse models had an ocular phenotype. Ocular abnormalities were more common in genes affected in the proximal tubulopathies (17/24, 71%) than elsewhere (7/43, 16%). They included structural features (coloboma, microphthalmia); refractive errors (myopia, astigmatism); crystal deposition (in oxalosis, cystinosis) and sclerochoroidal calcification (in Bartter, Gitelman syndromes). Retinal atrophy was common in the mitochondrial-associated tubulopathies. Structural abnormalities and crystal deposition were present from childhood, but sclerochoroidal calcification typically occurred after middle age. CONCLUSIONS Ocular abnormalities are uncommon in the genetic tubulopathies but may be helpful in recognizing the underlying genetic disease. The retinal expression and mouse phenotype data suggest that further ocular associations may become apparent with additional reports. Early identification may be necessary to monitor and treat visual complications.
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Affiliation(s)
- GeFei Yang
- Department of Medicine (Melbourne Health and Northern Health), The University of Melbourne, Royal Melbourne Hospital, Parkville, Australia
| | - Heather Mack
- Department of Surgery (Ophthalmology), The University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia
| | - Philip Harraka
- Department of Medicine (Melbourne Health and Northern Health), The University of Melbourne, Royal Melbourne Hospital, Parkville, Australia
| | - Deb Colville
- Department of Surgery (Ophthalmology), The University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia
| | - Judy Savige
- Department of Medicine (Melbourne Health and Northern Health), The University of Melbourne, Royal Melbourne Hospital, Parkville, Australia
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Szrok-Jurga S, Czumaj A, Turyn J, Hebanowska A, Swierczynski J, Sledzinski T, Stelmanska E. The Physiological and Pathological Role of Acyl-CoA Oxidation. Int J Mol Sci 2023; 24:14857. [PMID: 37834305 PMCID: PMC10573383 DOI: 10.3390/ijms241914857] [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: 08/25/2023] [Revised: 09/27/2023] [Accepted: 09/30/2023] [Indexed: 10/15/2023] Open
Abstract
Fatty acid metabolism, including β-oxidation (βOX), plays an important role in human physiology and pathology. βOX is an essential process in the energy metabolism of most human cells. Moreover, βOX is also the source of acetyl-CoA, the substrate for (a) ketone bodies synthesis, (b) cholesterol synthesis, (c) phase II detoxication, (d) protein acetylation, and (d) the synthesis of many other compounds, including N-acetylglutamate-an important regulator of urea synthesis. This review describes the current knowledge on the importance of the mitochondrial and peroxisomal βOX in various organs, including the liver, heart, kidney, lung, gastrointestinal tract, peripheral white blood cells, and other cells. In addition, the diseases associated with a disturbance of fatty acid oxidation (FAO) in the liver, heart, kidney, lung, alimentary tract, and other organs or cells are presented. Special attention was paid to abnormalities of FAO in cancer cells and the diseases caused by mutations in gene-encoding enzymes involved in FAO. Finally, issues related to α- and ω- fatty acid oxidation are discussed.
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Affiliation(s)
- Sylwia Szrok-Jurga
- Department of Biochemistry, Faculty of Medicine, Medical University of Gdansk, 80-211 Gdansk, Poland; (S.S.-J.); (J.T.); (A.H.)
| | - Aleksandra Czumaj
- Department of Pharmaceutical Biochemistry, Faculty of Pharmacy, Medical University of Gdansk, 80-211 Gdansk, Poland;
| | - Jacek Turyn
- Department of Biochemistry, Faculty of Medicine, Medical University of Gdansk, 80-211 Gdansk, Poland; (S.S.-J.); (J.T.); (A.H.)
| | - Areta Hebanowska
- Department of Biochemistry, Faculty of Medicine, Medical University of Gdansk, 80-211 Gdansk, Poland; (S.S.-J.); (J.T.); (A.H.)
| | - Julian Swierczynski
- Institue of Nursing and Medical Rescue, State University of Applied Sciences in Koszalin, 75-582 Koszalin, Poland;
| | - Tomasz Sledzinski
- Department of Pharmaceutical Biochemistry, Faculty of Pharmacy, Medical University of Gdansk, 80-211 Gdansk, Poland;
| | - Ewa Stelmanska
- Department of Biochemistry, Faculty of Medicine, Medical University of Gdansk, 80-211 Gdansk, Poland; (S.S.-J.); (J.T.); (A.H.)
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Albuquerque ALB, Dos Santos Borges R, Conegundes AF, Dos Santos EE, Fu FMM, Araujo CT, Vaz de Castro PAS, Simões E Silva AC. Inherited Fanconi syndrome. World J Pediatr 2023; 19:619-634. [PMID: 36729281 DOI: 10.1007/s12519-023-00685-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Accepted: 01/08/2023] [Indexed: 02/03/2023]
Abstract
BACKGROUND Fanconi-Debré-de Toni syndrome (also known as Fanconi renotubular syndrome, or FRST) profoundly increased the understanding of the functions of the proximal convoluted tubule (PCT) and provided important insights into the pathophysiology of several kidney diseases and drug toxicities. DATA SOURCES We searched Pubmed and Scopus databases to find relevant articles about FRST. This review article focuses on the physiology of the PCT, as well as on the physiopathology of FRST in children, its diagnosis, and treatment. RESULTS FRST encompasses a wide variety of inherited and acquired PCT alterations that lead to impairment of PCT reabsorption. In children, FRST often presents as a secondary feature of systemic disorders that impair energy supply, such as Lowe's syndrome, Dent's disease, cystinosis, hereditary fructose intolerance, galactosemia, tyrosinemia, Alport syndrome, and Wilson's disease. Although rare, congenital causes of FRST greatly impact the morbidity and mortality of patients and impose diagnostic challenges. Furthermore, its treatment is diverse and considers the ability of the clinician to identify the correct etiology of the disease. CONCLUSION The early diagnosis and treatment of pediatric patients with FRST improve the prognosis and the quality of life.
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Affiliation(s)
- Anna Luiza Braga Albuquerque
- Interdisciplinary Laboratory of Medical Investigation, Unit of Pediatric Nephrology, Faculty of Medicine, Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil
| | - Rafael Dos Santos Borges
- Interdisciplinary Laboratory of Medical Investigation, Unit of Pediatric Nephrology, Faculty of Medicine, Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil
| | - Ana Flávia Conegundes
- Interdisciplinary Laboratory of Medical Investigation, Unit of Pediatric Nephrology, Faculty of Medicine, Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil
| | - Erika Emmylaine Dos Santos
- Interdisciplinary Laboratory of Medical Investigation, Unit of Pediatric Nephrology, Faculty of Medicine, Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil
| | - Frederico Moreira Man Fu
- Interdisciplinary Laboratory of Medical Investigation, Unit of Pediatric Nephrology, Faculty of Medicine, Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil
| | - Clara Tavares Araujo
- Interdisciplinary Laboratory of Medical Investigation, Unit of Pediatric Nephrology, Faculty of Medicine, Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil
| | - Pedro Alves Soares Vaz de Castro
- Interdisciplinary Laboratory of Medical Investigation, Unit of Pediatric Nephrology, Faculty of Medicine, Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil
| | - Ana Cristina Simões E Silva
- Interdisciplinary Laboratory of Medical Investigation, Unit of Pediatric Nephrology, Faculty of Medicine, Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil.
- Department of Pediatrics, Faculty of Medicine, UFMG, Alfredo Balena Avenue, 190, 2Nd Floor, Room # 281, Belo Horizonte, MG, 30130-100, Brazil.
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Liang S, Wang Y, Kang M, Deng J, Chen L, Hong X, Hou FF, Zhang F. Generation and characterization of an inducible renal proximal tubule-specific CreERT2 mouse. Front Cell Dev Biol 2023; 11:1171637. [PMID: 37215091 PMCID: PMC10196630 DOI: 10.3389/fcell.2023.1171637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 04/19/2023] [Indexed: 05/24/2023] Open
Abstract
Protein reabsorption in renal proximal tubules is essential for maintaining nutrient homeostasis. Renal proximal tubule-specific gene knockout is a powerful method to assess the function of genes involved in renal proximal tubule protein reabsorption. However, the lack of inducible renal proximal tubule-specific Cre recombinase-expressing mouse strains hinders the study of gene function in renal proximal tubules. To facilitate the functional study of genes in renal proximal tubules, we developed an AMN CreERT2 knock-in mouse strain expressing a Cre recombinase-estrogen receptor fusion protein under the control of the promoter of the amnionless (AMN) gene, a protein reabsorption receptor in renal proximal tubules. AMN CreERT2 knock-in mice were generated using the CRISPR/Cas9 strategy, and the tissue specificity of Cre activity was investigated using the Cre/loxP reporter system. We showed that the expression pattern of CreERT2-mEGFP in AMN CreERT2 mice was consistent with that of the endogenous AMN gene. Furthermore, we showed that the Cre activity in AMN CreERT2 knock-in mice was only detected in renal proximal tubules with high tamoxifen induction efficiency. As a proof-of-principle study, we demonstrated that renal proximal tubule-specific knockout of Exoc4 using AMNCreERT2 led to albumin accumulation in renal proximal tubular epithelial cells. The AMN CreERT2 mouse is a powerful tool for conditional gene knockout in renal proximal tubules and should offer useful insight into the physiological function of genes expressed in renal proximal tubules.
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Affiliation(s)
| | | | | | | | | | | | - Fan Fan Hou
- *Correspondence: Fan Fan Hou, ; Fujian Zhang,
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Forst AL, Reichold M, Kleta R, Warth R. Distinct Mitochondrial Pathologies Caused by Mutations of the Proximal Tubular Enzymes EHHADH and GATM. Front Physiol 2021; 12:715485. [PMID: 34349672 PMCID: PMC8326905 DOI: 10.3389/fphys.2021.715485] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 06/28/2021] [Indexed: 12/18/2022] Open
Abstract
The mitochondria of the proximal tubule are essential for providing energy in this nephron segment, whose ATP generation is almost exclusively oxygen dependent. In addition, mitochondria are involved in a variety of metabolic processes and complex signaling networks. Proximal tubular mitochondrial dysfunction can therefore affect renal function in very different ways. Two autosomal dominantly inherited forms of renal Fanconi syndrome illustrate how multifaceted mitochondrial pathology can be: Mutation of EHHADH, an enzyme in fatty acid metabolism, results in decreased ATP synthesis and a consecutive transport defect. In contrast, mutations of GATM, an enzyme in the creatine biosynthetic pathway, leave ATP synthesis unaffected but do lead to mitochondrial protein aggregates, inflammasome activation, and renal fibrosis with progressive renal failure. In this review article, the distinct pathophysiological mechanisms of these two diseases are presented, which are examples of the spectrum of proximal tubular mitochondrial diseases.
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Affiliation(s)
- Anna-Lena Forst
- Medical Cell Biology, Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Markus Reichold
- Medical Cell Biology, Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Robert Kleta
- Centre for Nephrology, University College London, London, United Kingdom
| | - Richard Warth
- Medical Cell Biology, Institute of Physiology, University of Regensburg, Regensburg, Germany
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Koumakis E, Cormier C, Roux C, Briot K. The Causes of Hypo- and Hyperphosphatemia in Humans. Calcif Tissue Int 2021; 108:41-73. [PMID: 32285168 DOI: 10.1007/s00223-020-00664-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 01/20/2020] [Indexed: 12/11/2022]
Abstract
Phosphate homeostasis involves several major organs that are the skeleton, the intestine, the kidney, and parathyroid glands. Major regulators of phosphate homeostasis are parathormone, fibroblast growth factor 23, 1,25-dihydroxyvitamin D, which respond to variations of serum phosphate levels and act to increase or decrease intestinal absorption and renal tubular reabsorption, through the modulation of expression of transcellular transporters at the intestinal and/or renal tubular level. Any acquired or genetic dysfunction in these major organs or regulators may induce hypo- or hyperphosphatemia. The causes of hypo- and hyperphosphatemia are numerous. This review develops the main causes of acquired and genetic hypo- and hyperphosphatemia.
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Affiliation(s)
- Eugénie Koumakis
- Reference Center for Rare Disorders of Calcium and Phosphate Metabolism, Reference Center for Rare Genetic Bone Disorders, OSCAR Filière, Rheumatology Department, Cochin Hospital, AP-HP Centre-Paris University, 27 Rue du Faubourg Saint-Jacques, 75014, Paris, France.
| | - Catherine Cormier
- Reference Center for Rare Disorders of Calcium and Phosphate Metabolism, Reference Center for Rare Genetic Bone Disorders, OSCAR Filière, Rheumatology Department, Cochin Hospital, AP-HP Centre-Paris University, 27 Rue du Faubourg Saint-Jacques, 75014, Paris, France
| | - Christian Roux
- Reference Center for Rare Disorders of Calcium and Phosphate Metabolism, Reference Center for Rare Genetic Bone Disorders, OSCAR Filière, Rheumatology Department, Cochin Hospital, AP-HP Centre-Paris University, 27 Rue du Faubourg Saint-Jacques, 75014, Paris, France
| | - Karine Briot
- Reference Center for Rare Disorders of Calcium and Phosphate Metabolism, Reference Center for Rare Genetic Bone Disorders, OSCAR Filière, Rheumatology Department, Cochin Hospital, AP-HP Centre-Paris University, 27 Rue du Faubourg Saint-Jacques, 75014, Paris, France
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Lemaire M. Novel Fanconi renotubular syndromes provide insights in proximal tubule pathophysiology. Am J Physiol Renal Physiol 2020; 320:F145-F160. [PMID: 33283647 DOI: 10.1152/ajprenal.00214.2020] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The various forms of Fanconi renotubular syndromes (FRTS) offer significant challenges for clinicians and present unique opportunities for scientists who study proximal tubule physiology. This review will describe the clinical characteristics, genetic underpinnings, and underlying pathophysiology of the major forms of FRST. Although the classic forms of FRTS will be presented (e.g., Dent disease or Lowe syndrome), particular attention will be paid to five of the most recently discovered FRTS subtypes caused by mutations in the genes encoding for L-arginine:glycine amidinotransferase (GATM), solute carrier family 34 (type Ii sodium/phosphate cotransporter), member 1 (SLC34A1), enoyl-CoAhydratase/3-hydroxyacyl CoA dehydrogenase (EHHADH), hepatocyte nuclear factor 4A (HNF4A), or NADH dehydrogenase complex I, assembly factor 6 (NDUFAF6). We will explore how mutations in these genes revealed unexpected mechanisms that led to compromised proximal tubule functions. We will also describe the inherent challenges associated with gene discovery studies based on findings derived from small, single-family studies by focusing the story of FRTS type 2 (SLC34A1). Finally, we will explain how extensive alternative splicing of HNF4A has resulted in confusion with mutation nomenclature for FRTS type 4.
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Affiliation(s)
- Mathieu Lemaire
- Division of Nephrology and Cell Biology Program, SickKids Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Pediatrics, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
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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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Park DJ, Jang KS, Kim GH. Adult Idiopathic Renal Fanconi Syndrome: A Case Report. Electrolyte Blood Press 2018; 16:19-22. [PMID: 30899310 PMCID: PMC6414315 DOI: 10.5049/ebp.2018.16.2.19] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 02/20/2019] [Indexed: 11/16/2022] Open
Abstract
Renal Fanconi syndrome (RFS) is caused by generalized proximal tubular dysfunction and can be divided into hereditary and acquired form. Adult-onset RFS is usually associated with drug toxicity or systemic disorders, and modern molecular genetics may explain the etiology of previous idiopathic cases of RFS. Here, we report the case of a 52-year-old woman with RFS whose etiology could not be identified. She presented with features of phosphaturia, renal glucosuria, aminoaciduria, tubular proteinuria, and proximal renal tubular acidosis. Her family history was unremarkable, and previous medications were nonspecific. Her bone mineral density was compatible with osteoporosis, serum intact parathyroid hormone level was mildly elevated, and 25(OH) vitamin D level was insufficient. Her blood urea nitrogen and serum creatinine levels were 8.4 and 1.19 mg/dL, respectively (estimated glomerular filtration rate, 53 mL/min/1.73 m2). Percutaneous renal biopsy was performed but revealed no specific renal pathology, including mitochondrial morphology. No mutation was detected in EHHADH gene. We propose the possibility of involvement of other genes or molecules in this case of adult RFS.
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Affiliation(s)
- Dae Jin Park
- Department of Internal Medicine, Hanyang University College of Medicine, Seoul, Korea
| | - Ki-Seok Jang
- Department of Pathology, Hanyang University College of Medicine, Seoul, Korea
| | - Gheun-Ho Kim
- Department of Internal Medicine, Hanyang University College of Medicine, Seoul, Korea
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Kleta R, Bockenhauer D. Salt-Losing Tubulopathies in Children: What's New, What's Controversial? J Am Soc Nephrol 2018; 29:727-739. [PMID: 29237739 PMCID: PMC5827598 DOI: 10.1681/asn.2017060600] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Renal tubulopathies provide insights into the inner workings of the kidney, yet also pose therapeutic challenges. Because of the central nature of sodium in tubular transport physiology, disorders of sodium handling may affect virtually all aspects of the homeostatic functions of the kidney. Yet, owing to the rarity of these disorders, little clinical evidence regarding treatment exists. Consequently, treatment can vary widely between individual physicians and centers and is based mainly on understanding of renal physiology, reported clinical observations, and individual experiences. Salt-losing tubulopathies can affect all tubular segments, from the proximal tubule to the collecting duct. But the more frequently observed disorders are Bartter and Gitelman syndrome, which affect salt transport in the thick ascending limb of Henle's loop and/or the distal convoluted tubule, and these disorders generate the greatest controversies regarding management. Here, we review clinical and molecular aspects of salt-losing tubulopathies and discuss novel insights provided mainly by genetic investigations and retrospective clinical reviews. Additionally, we discuss controversial topics in the management of these disorders to highlight areas of importance for future clinical trials. International collaboration will be required to perform clinical studies to inform the treatment of these rare disorders.
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Affiliation(s)
- Robert Kleta
- UCL Centre for Nephrology and Great Ormond Street Hospital NHS Foundation Trust, London, United Kingdom
| | - Detlef Bockenhauer
- UCL Centre for Nephrology and Great Ormond Street Hospital NHS Foundation Trust, London, United Kingdom
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12
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Klootwijk ED, Reichold M, Unwin RJ, Kleta R, Warth R, Bockenhauer D. Renal Fanconi syndrome: taking a proximal look at the nephron. Nephrol Dial Transplant 2014; 30:1456-60. [PMID: 25492894 DOI: 10.1093/ndt/gfu377] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Accepted: 11/15/2014] [Indexed: 11/13/2022] Open
Abstract
Renal Fanconi syndrome (RFS) refers to the generalized dysfunction of the proximal tubule (PT) (Kleta R. Fanconi or not Fanconi? Lowe syndrome revisited. Clin J Am Soc Nephrol 2008; 3: 1244-1245). In its isolated form, RFS only affects the PT, but not the other nephron segments. The study of isolated RFS can thus provide specific insights into the function of the PT. In a recent paper, Klootwijk et al. investigated one such form of isolated RFS and revealed the underlying molecular basis (Klootwijk ED, Reichold M, Helip-Wooley A et al. Mistargeting of peroxisomal EHHADH and inherited renal Fanconi's syndrome. N Engl J Med 2014; 370: 129-138). The affected family had been described previously, demonstrating the typical features of RFS, such as low-molecular weight proteinuria, aminoaciduria, glycosuria and phosphaturia with consequent rickets; yet, importantly, patients had no evidence of impaired glomerular filtration (Tolaymat A, Sakarcan A, Neiberger R. Idiopathic Fanconi syndrome in a family. Part I. Clinical aspects. J Am Soc Nephrol 1992; 2: 1310-1317). Inheritance was consistent with an autosomal dominant mode. Klootwijk et al. discovered a surprising explanation: a heterozygous missense mutation causing partial mistargeting of the peroxisomal enzyme EHHADH to the mitochondria. Notably, disease causing was not the absence of the enzyme in the peroxisome, but its interference with mitochondrial function. The discovery of this novel disease mechanism not only confirmed the importance of mitochondrial function for PT transport, but also demonstrated the critical dependence of PT on fatty acid metabolism for energy generation.
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Affiliation(s)
| | - Markus Reichold
- Medical Cell Biology, Institute of Physiology, Regensburg, Germany
| | - Robert J Unwin
- Division of Medicine, University College London, London, UK
| | - Robert Kleta
- Centre for Nephrology, University College London, London, UK
| | - Richard Warth
- Medical Cell Biology, Institute of Physiology, Regensburg, Germany
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Abstract
A number of therapeutic drugs are toxic to the kidney proximal tubule (PT) and can cause the renal Fanconi syndrome (FS). The most frequently implicated drugs are cisplatin, ifosfamide, tenofovir, sodium valproate and aminoglycoside antibiotics, and the new oral iron chelator deferasirox has also recently been associated with FS. The incidence of full or partial FS is almost certainly under-estimated due to a lack of appropriate systematic studies, variations in definitions of tubular dysfunction and under-reporting of adverse events. The clinical features of FS are amino aciduria, low molecular weight proteinuria, hypophosphataemia, metabolic acidosis and glycosuria. The most serious complications are bone demineralization from urinary phosphate wasting and progressive decline in kidney function. Commonly used tests for kidney function such as estimated glomerular filtration rate and urine albumin/creatinine ratio are not sensitive markers of PT toxicity; patients at risk should thus be monitored with more appropriate tests, and drugs should be stopped or reduced in dose if toxicity occurs. Substantial recovery of PT function can occur after withdrawal of therapy, but this can take months and chronic damage may persist in some cases.
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Affiliation(s)
- A M Hall
- Swiss National Centre of Competence in Research (NCCR) Kidney Control of Homeostasis, Institute of Anatomy, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
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Hamilton AJ, Bingham C, McDonald TJ, Cook PR, Caswell RC, Weedon MN, Oram RA, Shields BM, Shepherd M, Inward CD, Hamilton-Shield JP, Kohlhase J, Ellard S, Hattersley AT. The HNF4A R76W mutation causes atypical dominant Fanconi syndrome in addition to a β cell phenotype. J Med Genet 2014; 51:165-9. [PMID: 24285859 PMCID: PMC3932761 DOI: 10.1136/jmedgenet-2013-102066] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Revised: 10/22/2013] [Accepted: 10/23/2013] [Indexed: 01/09/2023]
Abstract
BACKGROUND Mutation specific effects in monogenic disorders are rare. We describe atypical Fanconi syndrome caused by a specific heterozygous mutation in HNF4A. Heterozygous HNF4A mutations cause a beta cell phenotype of neonatal hyperinsulinism with macrosomia and young onset diabetes. Autosomal dominant idiopathic Fanconi syndrome (a renal proximal tubulopathy) is described but no genetic cause has been defined. METHODS AND RESULTS We report six patients heterozygous for the p.R76W HNF4A mutation who have Fanconi syndrome and nephrocalcinosis in addition to neonatal hyperinsulinism and macrosomia. All six displayed a novel phenotype of proximal tubulopathy, characterised by generalised aminoaciduria, low molecular weight proteinuria, glycosuria, hyperphosphaturia and hypouricaemia, and additional features not seen in Fanconi syndrome: nephrocalcinosis, renal impairment, hypercalciuria with relative hypocalcaemia, and hypermagnesaemia. This was mutation specific, with the renal phenotype not being seen in patients with other HNF4A mutations. In silico modelling shows the R76 residue is directly involved in DNA binding and the R76W mutation reduces DNA binding affinity. The target(s) selectively affected by altered DNA binding of R76W that results in Fanconi syndrome is not known. CONCLUSIONS The HNF4A R76W mutation is an unusual example of a mutation specific phenotype, with autosomal dominant atypical Fanconi syndrome in addition to the established beta cell phenotype.
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Affiliation(s)
- Alexander J Hamilton
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, Devon, UK
- Renal Unit, Royal Devon and Exeter NHS Foundation Trust, Exeter, Devon, UK
| | - Coralie Bingham
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, Devon, UK
- Renal Unit, Royal Devon and Exeter NHS Foundation Trust, Exeter, Devon, UK
| | - Timothy J McDonald
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, Devon, UK
| | - Paul R Cook
- University Hospital Southampton NHS Foundation Trust, Southampton, Hampshire, UK
| | - Richard C Caswell
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, Devon, UK
| | - Michael N Weedon
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, Devon, UK
| | - Richard A Oram
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, Devon, UK
| | - Beverley M Shields
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, Devon, UK
| | - Maggie Shepherd
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, Devon, UK
| | | | - Julian P Hamilton-Shield
- Bristol Royal Hospital for Children, Bristol, UK
- UBHT Education Centre, University of Bristol, Bristol, UK
| | | | - Sian Ellard
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, Devon, UK
| | - Andrew T Hattersley
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, Devon, UK
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15
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Klootwijk ED, Reichold M, Helip-Wooley A, Tolaymat A, Broeker C, Robinette SL, Reinders J, Peindl D, Renner K, Eberhart K, Assmann N, Oefner PJ, Dettmer K, Sterner C, Schroeder J, Zorger N, Witzgall R, Reinhold SW, Stanescu HC, Bockenhauer D, Jaureguiberry G, Courtneidge H, Hall AM, Wijeyesekera AD, Holmes E, Nicholson JK, O'Brien K, Bernardini I, Krasnewich DM, Arcos-Burgos M, Izumi Y, Nonoguchi H, Jia Y, Reddy JK, Ilyas M, Unwin RJ, Gahl WA, Warth R, Kleta R. Mistargeting of peroxisomal EHHADH and inherited renal Fanconi's syndrome. N Engl J Med 2014; 370:129-38. [PMID: 24401050 DOI: 10.1056/nejmoa1307581] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BACKGROUND In renal Fanconi's syndrome, dysfunction in proximal tubular cells leads to renal losses of water, electrolytes, and low-molecular-weight nutrients. For most types of isolated Fanconi's syndrome, the genetic cause and underlying defect remain unknown. METHODS We clinically and genetically characterized members of a five-generation black family with isolated autosomal dominant Fanconi's syndrome. We performed genomewide linkage analysis, gene sequencing, biochemical and cell-biologic investigations of renal proximal tubular cells, studies in knockout mice, and functional evaluations of mitochondria. Urine was studied with the use of proton nuclear magnetic resonance ((1)H-NMR) spectroscopy. RESULTS We linked the phenotype of this family's Fanconi's syndrome to a single locus on chromosome 3q27, where a heterozygous missense mutation in EHHADH segregated with the disease. The p.E3K mutation created a new mitochondrial targeting motif in the N-terminal portion of EHHADH, an enzyme that is involved in peroxisomal oxidation of fatty acids and is expressed in the proximal tubule. Immunocytofluorescence studies showed mistargeting of the mutant EHHADH to mitochondria. Studies of proximal tubular cells revealed impaired mitochondrial oxidative phosphorylation and defects in the transport of fluids and a glucose analogue across the epithelium. (1)H-NMR spectroscopy showed elevated levels of mitochondrial metabolites in urine from affected family members. Ehhadh knockout mice showed no abnormalities in renal tubular cells, a finding that indicates a dominant negative nature of the mutation rather than haploinsufficiency. CONCLUSIONS Mistargeting of peroxisomal EHHADH disrupts mitochondrial metabolism and leads to renal Fanconi's syndrome; this indicates a central role of mitochondria in proximal tubular function. The dominant negative effect of the mistargeted protein adds to the spectrum of monogenic mechanisms of Fanconi's syndrome. (Funded by the European Commission Seventh Framework Programme and others.).
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Affiliation(s)
- Enriko D Klootwijk
- From the Centre for Nephrology (E.D.K., H.C.S., D.B., G.J., H.C., A.M.H., R.J.U., R.K.) and Institute of Child Health (D.B., R.K.), University College London, and Biomolecular Medicine, Imperial College London (S.L.R., A.D.W., E.H., J.K.N.) - both in London; the Departments of Medical Cell Biology (M.R., C.B., D.P., C.S., R. Warth), Internal Medicine III (K.R.), Internal Medicine II (S.W.R.), and Molecular and Cellular Anatomy (R. Witzgall) and the Institutes of Functional Genomics (J.R., K.E., N.A., P.J.O., K.D.) and Pathology (J.S.), University of Regensburg, and the Department of Radiology, Barmherzige Brueder Hospital (N.Z.) - all in Regensburg, Germany; the National Human Genome Research Institute (A.H.-W., S.L.R., H.C.S., K.O., I.B., D.M.K., W.A.G., R.K.) and National Heart, Lung, and Blood Institute (Y.I.), National Institutes of Health, Bethesda, MD; the Division of Pediatric Nephrology, University of Florida, Jacksonville (A.T., M.I.); the Genome Biology Department, Australian National University, Canberra, ACT, Australia (M.A.-B.); Kitasato University Medical Center, Saitama, Japan (H.N.); and the Department of Pathology, Northwestern University, Chicago (Y.J., J.K.R.)
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16
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Bowden SA, Patel HP, Beebe A, McBride KL. Successful Medical Therapy for Hypophosphatemic Rickets due to Mitochondrial Complex I Deficiency Induced de Toni-Debré-Fanconi Syndrome. Case Rep Pediatr 2013; 2013:354314. [PMID: 24386581 PMCID: PMC3872385 DOI: 10.1155/2013/354314] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Accepted: 11/14/2013] [Indexed: 11/17/2022] Open
Abstract
Primary de Toni-Debré-Fanconi syndrome is a non-FGF23-mediated hypophosphatemic disorder due to a primary defect in renal proximal tubule cell function resulting in hyperphosphaturia, renal tubular acidosis, glycosuria, and generalized aminoaciduria. The orthopaedic sequela and response to treatment of this rare disorder are limited in the literature. Herein we report a long term followup of a 10-year-old female presenting at 1 year of age with rickets initially misdiagnosed as vitamin D deficiency rickets. She was referred to the metabolic bone and genetics clinics at 5 years of age with severe genu valgum deformities of 24 degrees and worsening rickets. She had polyuria, polydipsia, enuresis, and bone pain. Diagnosis of hypophosphatemic rickets due to de Toni-Debré-Fanconi syndrome was subsequently made. Respiratory chain enzyme analysis identified a complex I mitochondrial deficiency as the underlying cause. She was treated with phosphate (50-70 mg/kg/day), calcitriol (30 ng/kg/day), and sodium citrate with resolution of bone pain and normal growth. By 10 years of age, her genu valgus deformities were 4 degrees with healing of rickets. Her excellent orthopaedic outcome despite late proper medical therapy is likely due to the intrinsic renal tubular defect that is more responsive to combined alkali, phosphate, and calcitriol therapy.
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Affiliation(s)
- Sasigarn A. Bowden
- Division of Endocrinology, Nationwide Children's Hospital, The Ohio State University College of Medicine, 700 Children's Drive, Columbus, OH 43205, USA
| | - Hiren P. Patel
- Division of Nephrology, Nationwide Children's Hospital, The Ohio State University College of Medicine, Columbus, OH 43205, USA
| | - Allan Beebe
- Division of Orthopedics, Nationwide Children's Hospital, The Ohio State University College of Medicine, Columbus, OH 43205, USA
| | - Kim L. McBride
- Center for Cardiovascular and Pulmonary Research, Department of Pediatrics, Nationwide Children's Hospital, The Ohio State University College of Medicine, Columbus, OH 43205, USA
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17
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Bockenhauer D, Bichet DG. Inherited secondary nephrogenic diabetes insipidus: concentrating on humans. Am J Physiol Renal Physiol 2013; 304:F1037-42. [PMID: 23364801 DOI: 10.1152/ajprenal.00639.2012] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The study of human physiology is paramount to understanding disease and developing rational and targeted treatments. Conversely, the study of human disease can teach us a lot about physiology. Investigations into primary inherited nephrogenic diabetes insipidus (NDI) have contributed enormously to our understanding of the mechanisms of urinary concentration and identified the vasopressin receptor AVPR2, as well as the water channel aquaporin-2 (AQP2), as key players in water reabsorption in the collecting duct. Yet, there are also secondary forms of NDI, for instance as a complication of lithium treatment. The focus of this review is secondary NDI associated with inherited human diseases, such as Bartter syndrome or apparent mineralocorticoid excess. Currently, the underlying pathophysiology of this inherited secondary NDI is unclear, but there appears to be true AQP2 deficiency. To better understand the underlying mechanism(s), collaboration between clinical and experimental physiologists is essential to further investigate these observations in appropriate experimental models.
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Affiliation(s)
- D Bockenhauer
- UCL Institute of Child Health and Great Ormond Street Hospital for Children NHS Foundation Trust, London, United Kingdom.
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18
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Hall AM, Hendry BM, Nitsch D, Connolly JO. Tenofovir-associated kidney toxicity in HIV-infected patients: a review of the evidence. Am J Kidney Dis 2011; 57:773-80. [PMID: 21435764 DOI: 10.1053/j.ajkd.2011.01.022] [Citation(s) in RCA: 267] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2010] [Accepted: 01/27/2011] [Indexed: 01/11/2023]
Abstract
Tenofovir (TDF) is an effective and widely used treatment for both human immunodeficiency virus (HIV) and hepatitis B virus infection. Although studies suggest that TDF has a low overall toxicity profile and only a modest effect on estimated glomerular filtration rate, numerous case reports have since appeared in the literature describing TDF-associated renal tubular dysfunction, and this is now a significant source of HIV-related referrals to nephrologists. The main target of toxicity appears to be the proximal tubule, and in severe cases, patients can develop renal Fanconi syndrome. We review findings from recent studies in this area performed by ourselves and others and discuss our direct experience as practicing nephrologists. In particular, we discuss: (1) the nature and extent of TDF-associated kidney toxicity in the HIV-infected population, (2) potential underlying mechanisms of toxicity in the proximal tubule, (3) risk factors for developing tubular dysfunction, and (4) suggested strategies to monitor patients on TDF therapy.
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Affiliation(s)
- Andrew M Hall
- UCL Centre for Nephrology, Royal Free Campus, University College London, London, UK.
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20
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Wornell P, Crocker J, Wade A, Dixon J, Acott P. An Acadian variant of Fanconi syndrome. Pediatr Nephrol 2007; 22:1711-5. [PMID: 17690917 DOI: 10.1007/s00467-007-0553-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2007] [Revised: 05/23/2007] [Accepted: 05/23/2007] [Indexed: 10/23/2022]
Abstract
The Acadians were French settlers to Nova Scotia in the seventeenth century. In 1755, they were expelled by the British to various sites in the Americas, including Louisiana, where they are referred to as Cajuns. Many later migrated back to the Maritime Provinces of Canada. The objective of this study was to describe a series of pediatric patients representing an Acadian variant of Fanconi syndrome (AVFS). Nineteen children were diagnosed with AVFS between 1971 and 2006 and followed regularly. Data concerning demographics, growth, bone disease, and renal function at presentation and last observation were collected. The commonest reason for referral was assessment of genu valgum at 8.5 +/- 4.2 years (mean +/- SD) with hypophosphatemic rickets confirmed in all patients. Small-body habitus and short stature were confirmed in all patients. Therapy consisting of alkali replacement and phosphate and vitamin D supplements resulted in improvement of rickets and leg alignment but not stature (median height Z-score at presentation -2.05, range -3.6 to 0.21, vs. -2.05 at last observation, range -3.36 to 0.47). Creatinine clearance decreased (65.4 +/- 24.6 vs. 48.0 +/- 36.0 ml/min per 1.73 m(2), P < 0.05) and proteinuria increased (0.38 +/- 0.25 vs. 1.46 +/- 1.52 g/d, P < 0.05) during follow up of 8.4 +/- 6.1 years. Chronic kidney disease developed in 50% by age 13 years. No extrarenal manifestations were identified, although two patients developed lethal pulmonary fibrosis postrenal transplantation. AVFS is characterized by rickets responsive to solute therapy, short stature, and loss of renal function, with progressive proteinuria with age.
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Affiliation(s)
- Philip Wornell
- Department of Pediatrics, IWK Health Centre, Dalhouise University, 5850/5980 University Avenue, PO Box 9700, Halifax, Nova Scotia, B3K 6R8, Canada.
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21
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Hsu SY, Tsai IJ, Tsau YK. Comparison of growth in primary Fanconi syndrome and proximal renal tubular acidosis. Pediatr Nephrol 2005; 20:460-4. [PMID: 15703948 DOI: 10.1007/s00467-004-1771-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2004] [Revised: 11/05/2004] [Accepted: 11/05/2004] [Indexed: 10/25/2022]
Abstract
To compare the difference between primary proximal renal tubular acidosis (PRTA) and Fanconi syndrome (FS), and to find out possible risk factors for growth retardation, we studied the long-term growth, clinical, laboratory, and radiological findings associated with the treatment of six children with primary FS and 15 children with PRTA. The ages of the children with FS were much older than those with PRTA at initial diagnosis (7.03+/-3.82 vs. 1.63+/-1.56 years). The height standard deviation score (SDS) at the start of treatment was significantly lower in FS than in PRTA. Catch-up growth was noted in PRTA at the end of follow-up (initial height SDS -2.13+/-1.10 vs. last height SDS -1.33+/-1.43, P=0.023 by paired t-test), whereas apparent linear growth impairment was found in FS in terms of overall growth velocity index (82.70+/-8.37%) and height SDS (initial -3.25+/-0.95 vs. last -3.15+/-0.31, P=0.791). There was also a higher rate of rickets occurrence in FS (3/6 vs. 0/15 in PRTA). Hypophosphatemia during the follow-up period was more frequent for FS than PRTA (69.2+/-26.1% vs. 7.0+/-25.8%, P<0.001), whereas metabolic acidosis (blood HCO(3)<20 mmol/l) was less efficiently corrected in PRTA (49.1+/-20.5% vs. 25.2+/-21.6% in FS, P=0.028). Moreover, the height Delta SDS correlated well with the mean serum P level during the treatment period in these patients (R=0.528, P=0.014 for all children; R=0.917, P=0.01 for FS patients). Our data suggest that metabolic acidosis may not be the sole factor causing growth impairment in FS. Correction of metabolic acidosis may indeed improve growth in PRTA but not in FS. This study indicates that factors other than metabolic acidosis, such as phosphate depletion and delayed diagnosis/treatment, should be considered to be important causes of growth retardation in FS.
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Affiliation(s)
- Shu-Yeh Hsu
- Department of Pediatrics, National Taiwan University Hospital, No. 7 Chung-Shan South Road, 100 Taipei, Taiwan
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22
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Lichter-Konecki U, Broman KW, Blau EB, Konecki DS. Genetic and physical mapping of the locus for autosomal dominant renal Fanconi syndrome, on chromosome 15q15.3. Am J Hum Genet 2001; 68:264-8. [PMID: 11090339 PMCID: PMC1234925 DOI: 10.1086/316923] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2000] [Accepted: 10/24/2000] [Indexed: 11/03/2022] Open
Abstract
Autosomal dominant renal Fanconi syndrome is a genetic model for the study of proximal renal tubular transport pathology. We were able to map the locus for this disease to human chromosome 15q15.3 by genotyping a central Wisconsin pedigree with 10 affected individuals. After a whole-genome scan with highly polymorphic simple sequence repeat markers, a maximum LOD score of 3.01 was calculated for marker D15S659 on chromosome 15q15.3. Linkage and haplotype analysis for an additional 24 markers flanking D15S659 narrowed the interval to approximately 3 cM, with the two highest single-point LOD scores observed being 4.44 and 4.68 (for D15S182 and D15S537, respectively). Subsequently, a complete bacterial artificial chromosome contig was constructed, from the High Throughput Genomic Sequence Database, for the region bounded by D15S182 and D15S143. The identification of the gene and gene product altered in autosomal dominant renal Fanconi syndrome will allow the study of the physiology of proximal renal tubular transport.
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Affiliation(s)
- U Lichter-Konecki
- Center for Medical Genetics, Marshfield Medical Research Foundation, Marshfield, WI, USA
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23
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Abstract
Although inorganic sulfate is an essential and ubiquitous anion in human biology, it is infrequently assayed in clinical chemistry today. Serum sulfate is difficult to measure accurately without resorting to physicochemical methods, such as ion chromatography, although many other techniques have been described. It is strongly influenced by a variety of physiological factors, including age, diet, pregnancy, and drug ingestion. Urinary excretion is the principal mechanism of disposal for the excess sulfate produced by sulfur amino acid oxidation, and the kidney is the primary site of regulation. In renal failure, sulfoesters accumulate and hypersulfatemia contributes directly to the unmeasured anion gap characteristic of the condition. In contrast, sulfate in urine is readily assayed by a number of means, particularly nephelometry after precipitation as a barium salt. Sulfate is most commonly assayed today as part of the clinical workup for nephrolithiasis, because sulfate is a major contributor to the ionic strength of urine and alters the equilibrium constants governing saturation and precipitation of calcium salts. Total sulfate deficiency has hitherto not been described, although genetic defects in sulfate transporters have been associated recently with congenital osteochondrodystrophies that may be lethal. New insights into sulfate transport and its hormonal regulation may lead to new clinical applications of sulfate analysis in the future.
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Affiliation(s)
- D E Cole
- Department of Laboratory Medicine and Pathobiology, University of Toronto, ON.
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van de Moesdijk D, van Weel-Sipman MH. An infant with severe combined immunodeficiency syndrome, an alpha-thalassemia trait and renal Fanconi syndrome. Bone Marrow Transplant 2000; 26:97-9. [PMID: 10918411 DOI: 10.1038/sj.bmt.1702463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We describe an infant with severe combined immunodeficiency syndrome and an alpha-thalassemia trait who developed a renal Fanconi syndrome after his first stem cell transplantation. This syndrome consists of a generalized failure of proximal tubular reabsorption, which leads to a large number of metabolic disturbances. The etiology varies from inherited causes, including an idiopathic form, to acquired causes such as intoxications, immunological disorders and hemoglobinopathies. In this case report we discuss possible explanations of the Fanconi syndrome in our patient.
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Affiliation(s)
- D van de Moesdijk
- Department of Clinical Genetics, Leiden University Medical Center, Leiden, The Netherlands
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Darrigrand-Haag RA, Center SA, Randolph JF, Lewis RM, Wood PA. Congenital Fanconi syndrome associated with renal dysplasia in 2 Border Terriers. Vet Med (Auckl) 1996; 10:412-9. [PMID: 8947876 DOI: 10.1111/j.1939-1676.1996.tb02090.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- R A Darrigrand-Haag
- Department of Clinical Sciences, New York State College of Veterinary Medicine, Cornell University, Ithaca, USA
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