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Coroado MAHD, Tavares JMSFL, Verde AGIV, Rodrigues MDCPP, Silva LMCRDCN, Silva SMMFD, Mota MDCR, Braga JDS. Severe polyhydramnios as neonatal presentation of Bartter’s syndrome type IV. REVISTA BRASILEIRA DE SAÚDE MATERNO INFANTIL 2021. [DOI: 10.1590/1806-93042021000200018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Abstract Introduction: Bartter’s syndrome comprises a heterogeneous group of inherited salt-losing tubulopathies. There are two forms of clinical presentation: classical and neonatal, the most severe type. Types I and II account for most of the neonatal cases. Types III and V are usually less severe. Characteristically Bartter’s syndrome type IV is a saltlosing nephropathy with mild to severe neonatal symptoms, with a specific feature - sensorineural deafness. Bartter’s syndrome type IV is the least common of all recessive types of the disease. Description: the first reported case of a Portuguese child with neurosensorial deafness, polyuria, polydipsia and failure to thrive, born prematurely due to severe polyhydramnios, with the G47R mutation in the BSND gene that causes Bartter’s syndrome type IV. Discussion: there are few published cases of BS type IV due to this mutation and those reported mostly have moderate clinical manifestations which begin later in life. The poor phenotype-genotype relationship combined with the rarity of this syndrome usually precludes an antenatal diagnosis. In the presence of a severe polyhydramnios case, with no fetal malformation detected, normal karyotype and after maternal disease exclusion, autosomal recessive diseases, including tubulopathies, should always be suspected.
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Peces R, Mena R, Peces C, Barruz P, Trujillo H, Carreño A, Espinosa L, Selgas R, Lapunzina P, Nevado J. Historical and geographical distribution of the founder mutation c.610G>A; p.Ala204Thr in the CLCNKB gene linked to Bartter syndrome type III in Spain. Clin Kidney J 2021; 14:1990-1993. [PMID: 34345425 PMCID: PMC8323134 DOI: 10.1093/ckj/sfab083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 04/20/2021] [Indexed: 12/02/2022] Open
Affiliation(s)
- Ramón Peces
- Servicio de Nefrología-Adultos, Hospital Universitario La Paz. IdiPAZ. Universidad Autónoma, Madrid, Spain
| | - Rocío Mena
- Instituto de Genética Médica y Molecular (INGEMM), Hospital Universitario La Paz. IdiPAZ. Universidad Autónoma, Madrid, Spain
| | - Carlos Peces
- Area de Tecnología de la Información, SESCAM, Toledo, Spain
| | - Pilar Barruz
- Instituto de Genética Médica y Molecular (INGEMM), Hospital Universitario La Paz. IdiPAZ. Universidad Autónoma, Madrid, Spain
| | - Hernando Trujillo
- Servicio de Nefrología-Adultos, Hospital Universitario 12 de Octubre, Madrid, Spain
| | - Agustín Carreño
- Servicio de Nefrología, Hospital General Universitario de Ciudad Real, Ciudad Real, Spain
| | - Laura Espinosa
- Servicio de Nefrología-Infantil, Hospital Universitario La Paz. IdiPAZ. Universidad Autónoma, Madrid, Spain
| | - Rafael Selgas
- Servicio de Nefrología-Adultos, Hospital Universitario La Paz. IdiPAZ. Universidad Autónoma, Madrid, Spain
| | - Pablo Lapunzina
- Instituto de Genética Médica y Molecular (INGEMM), Hospital Universitario La Paz. IdiPAZ. Universidad Autónoma, Madrid, Spain.,CIBERER, ITHACA (European Reference Network), Madrid, Spain
| | - Julián Nevado
- Instituto de Genética Médica y Molecular (INGEMM), Hospital Universitario La Paz. IdiPAZ. Universidad Autónoma, Madrid, Spain.,CIBERER, ITHACA (European Reference Network), Madrid, Spain
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Sakamoto Y, Hasegawa K, Moriwaki S, Hara Y, Hamada Y, Sasaki S. A long-term study of the effects of SLC12A1 homozygous mutation (g.62382825G>A, p.Pro372Leu) in Japanese Black cattle. Anim Sci J 2020; 91:e13415. [PMID: 32671963 DOI: 10.1111/asj.13415] [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: 04/20/2020] [Revised: 05/27/2020] [Accepted: 06/05/2020] [Indexed: 10/23/2022]
Abstract
Recessive missense mutation in the solute carrier family 12, member 1 (SLC12A1) gene (g.62382825G>A) is associated with hydrallantois, which is the accumulation of fluid in the allantoic cavity of a pregnant animal, and usually causes fetal death in Japanese Black cattle. However, the symptoms of a homozygote with this mutation that do not result in fetal death have not previously been tracked and evaluated. In the present study, we observed a homozygote with the SLC12A1 risk allele over a long-term period. The calf did not show any obvious clinical symptoms, although it did exhibit a slight growth retardation that accompanied mild calciuria. At 28 months of age, the homozygote showed renal dysfunction, which in turn resulted in hydronephrosis. The time course of the symptoms was consistent with the phenotype of Bartter syndrome in humans. Additionally, the risk heterozygous genotype did not any effects on carcass traits, which indicates that eliminating the risk allele would not have any unfavorable effects. Therefore, we emphasize that both the fetal- and late-stage symptoms associated with the SLC12A1 risk allele compromise animal welfare, and consequently may result in severe economic losses for individual farmers if the SLC12A1 risk allele is not eliminated from the population.
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Affiliation(s)
- Yoichi Sakamoto
- Shimane Prefecture Livestock Technology Center, Izumo, Shimane, Japan
| | | | - Shunsuke Moriwaki
- Shimane Prefecture Livestock Technology Center, Izumo, Shimane, Japan
| | - Yoko Hara
- Matsue Livestock Hygiene Service Center, Matsune, Shimane, Japan
| | - Yuta Hamada
- Shimane Domestic Livestock Disease Identification Office, Izumo, Shimane, Japan
| | - Shinji Sasaki
- Faculty of Agriculture, University of the Ryukyus, Nishihara, Okinawa, Japan.,United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima, Japan
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Khandelwal P, Sabanadesan J, Sinha A, Hari P, Bagga A. Isolated nephrocalcinosis due to compound heterozygous mutations in renal outer medullary potassium channel. CEN Case Rep 2020; 9:232-236. [PMID: 32185747 DOI: 10.1007/s13730-020-00464-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 03/03/2020] [Indexed: 02/06/2023] Open
Abstract
Identification of a monogenic etiology is possible in a proportion of patients with childhood-onset nephrolithiasis or nephrocalcinosis. Bartter syndrome (BS), a hereditary tubulopathy characterized by polyuria, hypokalemic alkalosis and growth retardation that rarely presents with isolated nephrocalcinosis. Patients with defect in renal outer medullary potassium channel, encoded by the KCNJ1 gene causing BS type 2, typically present during the neonatal period. We describe a 14-year-old girl with mild late-onset BS type 2 with reported pathogenic compound heterozygous variations in exon 2 of KCNJ1 (c.146G > A and c.657C > G). This patient presented with isolated medullary nephrocalcinosis due to hypercalciuria; absence of hypokalemia and metabolic alkalosis was unique. This case highlights the importance of screening the KCNJ1 gene in patients with hypercalciuria and nephrocalcinosis, even in older children.
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Affiliation(s)
- Priyanka Khandelwal
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029, India
| | - Jasintha Sabanadesan
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029, India
| | - Aditi Sinha
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029, India
| | - Pankaj Hari
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029, India
| | - Arvind Bagga
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029, India.
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Penon-Portmann M, Lotz-Esquivel S, Chavez Carrera A, Jiménez-Hernández M, Alvarado-Romero D, Segura-Cordero S, Rimolo-Donadio F, Hevia-Urrutia F, Mora-Guevara A, Saborío-Rocafort M, Jiménez-Arguedas G, Badilla-Porras R. Wilson disease in Costa Rica: Pediatric phenotype and genotype characterization. JIMD Rep 2020; 52:55-62. [PMID: 32154060 PMCID: PMC7052697 DOI: 10.1002/jmd2.12098] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 01/14/2020] [Accepted: 01/17/2020] [Indexed: 12/20/2022] Open
Abstract
Introduction The prevalence of Wilson disease (WD) in Costa Rica is among the highest reported in the world, 4.9:100 000. Previous investigators have also described a burden of autosomal recessive conditions in this country. Genetic testing for WD began in 2010 as a strategy for earlier detection due to the country's high prevalence. Here we describe what we have learned about the genotype and phenotype of the Costa Rican pediatric population with WD. Methods We completed a retrospective review of medical records from pediatric individuals (<18 years of age) with molecular testing for ATP7B between 2010 and 2015. We documented phenotype and genotype for cases with WD as defined by the international scoring system. Results Thirty-four WD cases from 28 families were included, 15 female and 19 male patients. The most frequent pathogenic variant in ATP7B was NM_000053:c.3809A>G, p.Asn1270Ser, with 58.8% of affected individuals homozygous for this variant. Age of diagnosis ranged from 1 to 17 years, with an average of 8.8 ± 3.6 years. All individuals who presented with acute liver failure (n = 6) were homozygous for the p.Asn1270Ser variant (Chi-squared, P < .05). Discussion Molecular testing has facilitated the detection of presymptomatic patients with WD in Costa Rica. We hope that ongoing efforts in the delivery of clinical services lead to optimized molecular screening for WD and other genetic conditions in Costa Rica.
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Affiliation(s)
- Monica Penon-Portmann
- Servicio de Genética y Enfermedades Metabólicas, Departamento de Pediatría, Hospital Nacional de Niños, "Dr. Carlos Sáenz Herrera", Caja Costarricense de Seguro Social & Sistema de Estudios de Posgrado Universidad de Costa Rica San José Costa Rica.,Division of Medical Genetics, Department of Pediatrics & Institute for Human Genetics University of California San Francisco San Francisco California
| | - Stephanie Lotz-Esquivel
- Clínica Multidisciplinaria de Enfermedades Raras y Huérfanas & Unidad de Investigación, Departamento de Medicina Interna, Hospital San Juan de Dios Caja Costarricense de Seguro Social San José Costa Rica
| | - Alejandra Chavez Carrera
- Division of Medical Genetics, Department of Pediatrics & Institute for Human Genetics University of California San Francisco San Francisco California.,Escuela de Medicina, Colegio de Ciencias de la Salud Universidad San Francisco de Quito Quito Ecuador
| | - Mildred Jiménez-Hernández
- Programa Nacional de Tamizaje Neonatal Caja Costarricense de Seguro Social San José Costa Rica.,Laboratorio Nacional de Tamizaje Neonatal y Alto Riesgo Caja Costarricense de Seguro Social San José Costa Rica
| | - Danny Alvarado-Romero
- Programa Nacional de Tamizaje Neonatal Caja Costarricense de Seguro Social San José Costa Rica.,Laboratorio Nacional de Tamizaje Neonatal y Alto Riesgo Caja Costarricense de Seguro Social San José Costa Rica
| | - Sharon Segura-Cordero
- Clínica Multidisciplinaria de Enfermedades Raras y Huérfanas & Unidad de Investigación, Departamento de Medicina Interna, Hospital San Juan de Dios Caja Costarricense de Seguro Social San José Costa Rica
| | - Fiorella Rimolo-Donadio
- Unidad de Trasplante, Departamento de Cirugía, Hospital Nacional de Niños, "Dr. Carlos Sáenz Herrera" Caja Costarricense de Seguro Social San José Costa Rica
| | - Francisco Hevia-Urrutia
- Servicio de Gastroenterología, Sección de Medicina, Hospital San Juan de Dios Caja Costarricense de Seguro Social San José Costa Rica
| | - Alfredo Mora-Guevara
- Servicio de Gastroenterología, Departamento de Pediatría, Hospital Nacional de Niños, "Dr. Carlos Sáenz Herrera" Caja Costarricense de Seguro Social San José Costa Rica
| | - Manuel Saborío-Rocafort
- Servicio de Genética y Enfermedades Metabólicas, Departamento de Pediatría, Hospital Nacional de Niños, "Dr. Carlos Sáenz Herrera", Caja Costarricense de Seguro Social & Sistema de Estudios de Posgrado Universidad de Costa Rica San José Costa Rica.,Programa Nacional de Tamizaje Neonatal Caja Costarricense de Seguro Social San José Costa Rica
| | - Gabriela Jiménez-Arguedas
- Servicio de Gastroenterología, Departamento de Pediatría, Hospital Nacional de Niños, "Dr. Carlos Sáenz Herrera" Caja Costarricense de Seguro Social San José Costa Rica
| | - Ramsés Badilla-Porras
- Servicio de Genética y Enfermedades Metabólicas, Departamento de Pediatría, Hospital Nacional de Niños, "Dr. Carlos Sáenz Herrera", Caja Costarricense de Seguro Social & Sistema de Estudios de Posgrado Universidad de Costa Rica San José Costa Rica.,Programa Nacional de Tamizaje Neonatal Caja Costarricense de Seguro Social San José Costa Rica
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Glen WB, Peterseim MMW, Badilla R, Znoyko I, Bourg A, Wilson R, Hardiman G, Wolff D, Martinez J. A high prevalence of biallelic RPE65 mutations in Costa Rican children with Leber congenital amaurosis and early-onset retinal dystrophy. Ophthalmic Genet 2019; 40:110-117. [PMID: 30870047 DOI: 10.1080/13816810.2019.1582069] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
BACKGROUND Leber congenital amaurosis (LCA) and early-onset retinal dystrophy (EORD), are primary causes of inherited childhood blindness. Both are autosomal recessive diseases, with mutations in more than 25 genes explaining approximately ~70% of cases. However, the genetic cause for many cases remains unclear. Sequencing studies from genetically isolated populations with increased prevalence of a disorder has proven useful for rare variant studies, making Costa Rica an ideal place to study LCA/EORD genetics. MATERIALS AND METHODS Twenty-eight affected children (25 LCA, three EORD) and their immediate family members, totaling 52 individuals (30 affected) from 22 families, were sequenced. Whole exome sequencing was performed on all affected individuals. Available parents were analyzed either by whole exome sequencing (WES) or Sanger sequencing to determine transmission. RESULTS All affected individuals demonstrated compound heterozygous or homozygous mutations in known Inherited Retinal Disease (IRD) associated genes. Twelve variants were identified in at least one individual in three genes, RDH12, RPE65, and USH2A. Four recurrent RPE65 mutations were observed in 97% of individuals and 95% of families. All patients with LCA and two of the three individuals with EORD had biallelic mutations in RPE65; one child with EORD had a homozygous RDH12 mutation. CONCLUSIONS These data suggest that the majority of LCA/EORD in Costa Rica is due to four founder mutations in RPE65 which have been maintained in this genetically isolated population. This finding is of great clinical significance due to the availability of gene therapy recently approved in the US and European Union for patients with biallelic RPE65 defects.
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Affiliation(s)
- W Bailey Glen
- a Pathology and Laboratory Medicine , Medical University of South Carolina.,b Center for Genomic Medicine , Medical University of South Carolina
| | | | - Ramses Badilla
- d Genetics and Metabolism , National Children's Hospital , San José , Costa Rica.,e Caja Costarricense del Seguro Social
| | - Iya Znoyko
- a Pathology and Laboratory Medicine , Medical University of South Carolina
| | - Andre Bourg
- f Department of Medicine , Medical University of South Carolina
| | - Robert Wilson
- a Pathology and Laboratory Medicine , Medical University of South Carolina.,b Center for Genomic Medicine , Medical University of South Carolina
| | - Gary Hardiman
- b Center for Genomic Medicine , Medical University of South Carolina.,f Department of Medicine , Medical University of South Carolina.,g Institute for Global Food Security , Queen's University Belfast
| | - Daynna Wolff
- a Pathology and Laboratory Medicine , Medical University of South Carolina
| | - Joaquin Martinez
- e Caja Costarricense del Seguro Social.,h Division of Ophthalmology , National Children's Hospital , San José , Costa Rica
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7
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Sun M, Ning J, Xu W, Zhang H, Zhao K, Li W, Li G, Li S. Genetic heterogeneity in patients with Bartter syndrome type 1. Mol Med Rep 2016; 15:581-590. [PMID: 28000888 PMCID: PMC5364841 DOI: 10.3892/mmr.2016.6063] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 11/01/2016] [Indexed: 12/28/2022] Open
Abstract
Bartter syndrome (BS) type 1 is an autosomal recessive kidney disorder caused by loss-of-function mutations in the solute carrier family 12 member 1 (SLC12A1) gene. To date, 72 BS type 1 patients harboring SLC12A1 mutations have been documented. Of these 144 alleles studied, 68 different disease-causing mutations have been detected in 129 alleles, and no mutation was detected in the remaining 15 alleles. The mutation types included missense/nonsense mutations, splicing mutations and small insertions and deletions ranging from 1 to 4 nucleotides. A large deletion encompassing a whole exon in the SLC12A1 gene has not yet been reported. The current study initially identified an undocumented homozygous frameshift mutation (c.1833delT) by Sanger sequencing analysis of a single infant with BS type 1. However, in a subsequent analysis, the mutation was detected only in the father's DNA. Upon further investigation using a next-generation sequencing approach, a deletion in exons 14 and 15 in both the patient and patient's mother was detected. The deletion was subsequently confirmed by use of a long-range polymerase chain reaction and was determined to be 3.16 kb in size based on sequencing of the junction fragment. The results of the present study demonstrated that pathogenic variants of SLC12A1 are heterogeneous. Large deletions appear to serve an etiological role in BS type 1, and may be more prevalent than previously thought.
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Affiliation(s)
- Mingran Sun
- Department of Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma, OK 73117, USA
| | - Jing Ning
- Department of Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma, OK 73117, USA
| | - Weihong Xu
- Department of Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma, OK 73117, USA
| | - Han Zhang
- Department of Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma, OK 73117, USA
| | - Kaishu Zhao
- Department of Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma, OK 73117, USA
| | - Wenfu Li
- Department of Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma, OK 73117, USA
| | - Guiying Li
- Key Laboratory for Molecular Enzymology and Engineering, The Ministry of Education, School of Life Sciences, Jilin University, Changchun, Jilin 130012, P.R. China
| | - Shibo Li
- Department of Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma, OK 73117, USA
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8
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Sasaki S, Hasegawa K, Higashi T, Suzuki Y, Sugano S, Yasuda Y, Sugimoto Y. A missense mutation in solute carrier family 12, member 1 (SLC12A1) causes hydrallantois in Japanese Black cattle. BMC Genomics 2016; 17:724. [PMID: 27613513 PMCID: PMC5016959 DOI: 10.1186/s12864-016-3035-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2016] [Accepted: 08/24/2016] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND Hydrallantois is the excessive accumulation of fluid within the allantoic cavity in pregnant animals and is associated with fetal mortality. Although the incidence of hydrallantois is very low in artificial insemination breeding programs in cattle, recently 38 cows with the phenotypic appearance of hydrallantois were reported in a local subpopulation of Japanese Black cattle. Of these, 33 were traced back to the same sire; however, both their parents were reported healthy, suggesting that hydrallantois is a recessive inherited disorder. To identify autozygous chromosome segments shared by individuals with hydrallantois and the causative mutation in Japanese Black cattle, we performed autozygosity mapping using single-nucleotide polymorphism (SNP) array and exome sequencing. RESULTS Shared haplotypes of the affected fetuses spanned 3.52 Mb on bovine chromosome 10. Exome sequencing identified a SNP (g.62382825G > A, p.Pro372Leu) in exon 10 of solute carrier family 12, member 1 (SLC12A1), the genotype of which was compatible with recessive inheritance. SLC12A1 serves as a reabsorption molecule of Na(+)-K(+)-2Cl(-) in the apical membrane of the thick ascending limb of the loop of Henle in the kidney. We observed that the concentration of Na(+)-Cl(-) increased in allantoic fluid of homozygous SLC12A1 (g.62382825G > A) in a hydrallantois individual. In addition, SLC12A1-positive signals were localized at the apical membrane in the kidneys of unaffected fetuses, whereas they were absent from the apical membrane in the kidneys of affected fetuses. These results suggested that p.Pro372Leu affects the membrane localization of SLC12A1, and in turn, may impair its transporter activity. Surveillance of the risk-allele frequency revealed that the carriers were restricted to the local subpopulation of Japanese Black cattle. Moreover, we identified a founder individual that carried the mutation (g.62382825G > A). CONCLUSIONS In this study, we mapped the shared haplotypes of affected fetuses using autozygosity mapping and identified a de novo mutation in the SLC12A1 gene that was associated with hydrallantois in Japanese Black cattle. In kidneys of hydrallantois-affected fetuses, the mutation in SLC12A1 impaired the apical membrane localization of SLC12A1 and reabsorption of Na(+)-K(+)-2Cl(-) in the thick ascending limb of the loop of Henle, leading to a defect in the concentration of urine via the countercurrent mechanism. Consequently, the affected fetuses exhibited polyuria that accumulated in the allantoic cavity. Surveillance of the risk-allele frequency indicated that carriers were not widespread throughout the Japanese Black cattle population. Moreover, we identified the founder individual, and thus could effectively manage the disorder in the population.
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Affiliation(s)
- Shinji Sasaki
- Shirakawa Institute of Animal Genetics, Japan Livestock Technology Association, Odakura, Nishigo, Fukushima 961-8061 Japan
| | - Kiyotoshi Hasegawa
- Shimane Prefecture Livestock Technology Center, Koshi, Izumo, Shimane 693-0031 Japan
| | - Tomoko Higashi
- Shimane Prefecture Livestock Division Livestock Hygiene Research Office, Jinzaioki, Izumo, Shimane 699-0822 Japan
| | - Yutaka Suzuki
- Department of Medical Genome Sciences, and Department of Computational Biology, Graduate School of Frontier Sciences, The University of Tokyo, Chiba, 277-8562 Japan
| | - Sumio Sugano
- Department of Medical Genome Sciences, and Department of Computational Biology, Graduate School of Frontier Sciences, The University of Tokyo, Chiba, 277-8562 Japan
| | - Yasuaki Yasuda
- Shimane Prefecture Livestock Technology Center, Koshi, Izumo, Shimane 693-0031 Japan
| | - Yoshikazu Sugimoto
- Shirakawa Institute of Animal Genetics, Japan Livestock Technology Association, Odakura, Nishigo, Fukushima 961-8061 Japan
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Caceres PS, Mendez M, Haque MZ, Ortiz PA. Vesicle-associated Membrane Protein 3 (VAMP3) Mediates Constitutive Trafficking of the Renal Co-transporter NKCC2 in Thick Ascending Limbs: ROLE IN RENAL FUNCTION AND BLOOD PRESSURE. J Biol Chem 2016; 291:22063-22073. [PMID: 27551042 PMCID: PMC5063989 DOI: 10.1074/jbc.m116.735167] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Indexed: 02/04/2023] Open
Abstract
Renal cells of the thick ascending limb (TAL) reabsorb NaCl via the apical Na+/K+/2Cl- co-transporter NKCC2. Trafficking of NKCC2 to the apical surface regulates NKCC2-mediated NaCl absorption and blood pressure. The molecular mechanisms by which NKCC2 reaches the apical surface and their role in renal function and maintenance of blood pressure are poorly characterized. Here we report that NKCC2 interacts with the vesicle fusion protein VAMP3, and they co-localize at the TAL apical surface. We observed that silencing VAMP3 in vivo blocks constitutive NKCC2 exocytic delivery, decreasing the amount of NKCC2 at the TAL apical surface. VAMP3 is not required for cAMP-stimulated NKCC2 exocytic delivery. Additionally, genetic deletion of VAMP3 in mice decreased total expression of NKCC2 in the TAL and lowered blood pressure. Consistent with these results, urinary excretion of water and electrolytes was higher in VAMP3 knock-out mice, which produced more diluted urine. We conclude that VAMP3 interacts with NKCC2 and mediates its constitutive exocytic delivery to the apical surface. Additionally, VAMP3 is required for normal NKCC2 expression, renal function, and blood pressure.
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Affiliation(s)
- Paulo S Caceres
- From the Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Hospital, Detroit, Michigan 48202, the Department of Physiology, Wayne State University, Detroit, Michigan 48202, and
| | - Mariela Mendez
- From the Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Hospital, Detroit, Michigan 48202
| | - Mohammed Z Haque
- From the Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Hospital, Detroit, Michigan 48202, the Interim Translational Research Institute, Academic Health System, Hamad Medical Corporation, 16060 Doha, Qatar
| | - Pablo A Ortiz
- From the Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Hospital, Detroit, Michigan 48202, the Department of Physiology, Wayne State University, Detroit, Michigan 48202, and
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Lykke K, Töllner K, Feit PW, Erker T, MacAulay N, Löscher W. The search for NKCC1-selective drugs for the treatment of epilepsy: Structure-function relationship of bumetanide and various bumetanide derivatives in inhibiting the human cation-chloride cotransporter NKCC1A. Epilepsy Behav 2016; 59:42-9. [PMID: 27088517 DOI: 10.1016/j.yebeh.2016.03.021] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Revised: 03/11/2016] [Accepted: 03/12/2016] [Indexed: 11/30/2022]
Abstract
The Na(+)-K(+)-Cl(-) cotransporter NKCC1 plays a major role in the regulation of intraneuronal Cl(-) concentration. Abnormal functionality of NKCC1 has been implicated in several brain disorders, including epilepsy. Bumetanide is the only available selective NKCC1 inhibitor, but also inhibits NKCC2, which can cause severe adverse effects during treatment of brain disorders. A NKCC1-selective bumetanide derivative would therefore be a desirable option. In the present study, we used the Xenopus oocyte heterologous expression system to compare the effects of bumetanide and several derivatives on the two major human splice variants of NKCCs, hNKCC1A and hNKCC2A. The derivatives were selected from a series of ~5000 3-amino-5-sulfamoylbenzoic acid derivatives, covering a wide range of structural modifications and diuretic potencies. To our knowledge, such structure-function relationships have not been performed before for NKCC1. Half maximal inhibitory concentrations (IC50s) of bumetanide were 0.68 (hNKCC1A) and 4.0μM (hNKCC2A), respectively, indicating that this drug is 6-times more potent to inhibit hNKCC1A than hNKCC2A. Side chain substitutions in the bumetanide molecule variably affected the potency to inhibit hNKCC1A. This allowed defining the minimal structural requirements necessary for ligand interaction. Unexpectedly, only a few of the bumetanide derivatives examined were more potent than bumetanide to inhibit hNKCC1A, and most of them also inhibited hNKCC2A, with a highly significant correlation between IC50s for the two NKCC isoforms. These data indicate that the structural requirements for inhibition of NKCC1 and NKCC2 are similar, which complicates development of bumetanide-related compounds with high selectivity for NKCC1.
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Affiliation(s)
- Kasper Lykke
- Department of Neuroscience and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Kathrin Töllner
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany
| | - Peter W Feit
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany
| | - Thomas Erker
- Department of Medicinal Chemistry, University of Vienna, Vienna, Austria
| | - Nanna MacAulay
- Department of Neuroscience and Pharmacology, University of Copenhagen, Copenhagen, Denmark.
| | - Wolfgang Löscher
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany.
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Hartmann AM, Nothwang HG. Molecular and evolutionary insights into the structural organization of cation chloride cotransporters. Front Cell Neurosci 2015; 8:470. [PMID: 25653592 PMCID: PMC4301019 DOI: 10.3389/fncel.2014.00470] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 12/30/2014] [Indexed: 01/26/2023] Open
Abstract
Cation chloride cotransporters (CCC) play an essential role for neuronal chloride homeostasis. K(+)-Cl(-) cotransporter (KCC2), is the principal Cl(-)-extruder, whereas Na(+)-K(+)-Cl(-) cotransporter (NKCC1), is the major Cl(-)-uptake mechanism in many neurons. As a consequence, the action of the inhibitory neurotransmitters gamma-aminobutyric acid (GABA) and glycine strongly depend on the activity of these two transporters. Knowledge of the mechanisms involved in ion transport and regulation is thus of great importance to better understand normal and disturbed brain function. Although no overall 3-dimensional crystal structures are yet available, recent molecular and phylogenetic studies and modeling have provided new and exciting insights into structure-function relationships of CCC. Here, we will summarize our current knowledge of the gross structural organization of the proteins, their functional domains, ion binding and translocation sites, and the established role of individual amino acids (aa). A major focus will be laid on the delineation of shared and distinct organizational principles between KCC2 and NKCC1. Exploiting the richness of recently generated genome data across the tree of life, we will also explore the molecular evolution of these features.
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Affiliation(s)
- Anna-Maria Hartmann
- Systematics and Evolutionary Biology Group, Institute for Biology and Environmental Sciences, Carl von Ossietzky University Oldenburg Oldenburg, Germany
| | - Hans Gerd Nothwang
- Neurogenetics Group, Center of Excellence Hearing4All, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg Oldenburg, Germany ; Research Center for Neurosensory Sciences, Carl von Ossietzky University Oldenburg Oldenburg, Germany
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12
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Castrop H, Schießl IM. Physiology and pathophysiology of the renal Na-K-2Cl cotransporter (NKCC2). Am J Physiol Renal Physiol 2014; 307:F991-F1002. [PMID: 25186299 DOI: 10.1152/ajprenal.00432.2014] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The Na-K-2Cl cotransporter (NKCC2; BSC1) is located in the apical membrane of the epithelial cells of the thick ascending limb of the loop of Henle (TAL). NKCC2 facilitates ∼20–25% of the reuptake of the total filtered NaCl load. NKCC2 is therefore one of the transport proteins with the highest overall reabsorptive capacity in the kidney. Consequently, even subtle changes in NKCC2 transport activity considerably alter the renal reabsorptive capacity for NaCl and eventually lead to perturbations of the salt and water homoeostasis. In addition to facilitating the bulk reabsorption of NaCl in the TAL, NKCC2 transport activity in the macula densa cells of the TAL constitutes the initial step of the tubular-vascular communication within the juxtaglomerular apparatus (JGA); this communications allows the TAL to modulate the preglomerular resistance of the afferent arteriole and the renin secretion from the granular cells of the JGA. This review provides an overview of our current knowledge with respect to the general functions of NKCC2, the modulation of its transport activity by different regulatory mechanisms, and new developments in the pathophysiology of NKCC2-dependent renal NaCl transport.
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Affiliation(s)
- Hayo Castrop
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Ina Maria Schießl
- Institute of Physiology, University of Regensburg, Regensburg, Germany
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Vona B, Neuner C, El Hajj N, Schneider E, Farcas R, Beyer V, Zechner U, Keilmann A, Poot M, Bartsch O, Nanda I, Haaf T. Disruption of the ATE1 and SLC12A1 Genes by Balanced Translocation in a Boy with Non-Syndromic Hearing Loss. Mol Syndromol 2013; 5:3-10. [PMID: 24550759 DOI: 10.1159/000355443] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/05/2013] [Indexed: 01/21/2023] Open
Abstract
We report on a boy with non-syndromic hearing loss and an apparently balanced translocation t(10;15)(q26.13;q21.1). The same translocation was found in the normally hearing brother, father and paternal grandfather; however, this does not exclude its involvement in disease pathogenesis, for example, by unmasking a second mutation. Breakpoint analysis via FISH with BAC clones and long-range PCR products revealed a disruption of the arginyltransferase 1 (ATE1) gene on translocation chromosome 10 and the solute carrier family 12, member 1 gene (SLC12A1) on translocation chromosome 15. SNP array analysis revealed neither loss nor gain of chromosomal regions in the affected child, and a targeted gene enrichment panel consisting of 130 known deafness genes was negative for pathogenic mutations. The expression patterns in zebrafish and humans did not provide evidence for ear-specific functions of the ATE1 and SLC12A1 genes. Sanger sequencing of the 2 genes in the boy and 180 GJB2 mutation-negative hearing-impaired individuals did not detect homozygous or compound heterozygous pathogenic mutations. Our study demonstrates the many difficulties in unraveling the molecular causes of a heterogeneous phenotype. We cannot directly implicate disruption of ATE1 and/or SLC12A1 to the abnormal hearing phenotype; however, mutations in these genes may have a role in polygenic or multifactorial forms of hearing impairment. On the other hand, it is conceivable that our patient carries a disease-causing mutation in a so far unidentified deafness gene. Evidently, disruption of ATE1 and/or SLC12A1 gene function alone does not have adverse effects.
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Affiliation(s)
- B Vona
- Institute of Human Genetics, Julius Maximilians University, Wuerzburg, Germany
| | - C Neuner
- Institute of Human Genetics, Julius Maximilians University, Wuerzburg, Germany
| | - N El Hajj
- Institute of Human Genetics, Julius Maximilians University, Wuerzburg, Germany
| | - E Schneider
- Institute of Human Genetics, Julius Maximilians University, Wuerzburg, Germany
| | - R Farcas
- Institute of Human Genetics, Department of ORL, University Medical Center, Mainz, Germany
| | - V Beyer
- Institute of Human Genetics, Department of ORL, University Medical Center, Mainz, Germany
| | - U Zechner
- Institute of Human Genetics, Department of ORL, University Medical Center, Mainz, Germany
| | - A Keilmann
- Division of Communication Disorders, Department of ORL, University Medical Center, Mainz, Germany
| | - M Poot
- Department of Medical Genetics, University Medical Center, Utrecht, The Netherlands
| | - O Bartsch
- Institute of Human Genetics, Department of ORL, University Medical Center, Mainz, Germany
| | - I Nanda
- Institute of Human Genetics, Julius Maximilians University, Wuerzburg, Germany
| | - T Haaf
- Institute of Human Genetics, Julius Maximilians University, Wuerzburg, Germany
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Gagnon KB, Delpire E. Physiology of SLC12 transporters: lessons from inherited human genetic mutations and genetically engineered mouse knockouts. Am J Physiol Cell Physiol 2013; 304:C693-714. [PMID: 23325410 DOI: 10.1152/ajpcell.00350.2012] [Citation(s) in RCA: 116] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Among the over 300 members of the solute carrier (SLC) group of integral plasma membrane transport proteins are the nine electroneutral cation-chloride cotransporters belonging to the SLC12 gene family. Seven of these transporters have been functionally described as coupling the electrically silent movement of chloride with sodium and/or potassium. Although in silico analysis has identified two additional SLC12 family members, no physiological role has been ascribed to the proteins encoded by either the SLC12A8 or the SLC12A9 genes. Evolutionary conservation of this gene family from protists to humans confirms their importance. A wealth of physiological, immunohistochemical, and biochemical studies have revealed a great deal of information regarding the importance of this gene family to human health and disease. The sequencing of the human genome has provided investigators with the capability to link several human diseases with mutations in the genes encoding these plasma membrane proteins. The availability of bacterial artificial chromosomes, recombination engineering techniques, and the mouse genome sequence has simplified the creation of targeting constructs to manipulate the expression/function of these cation-chloride cotransporters in the mouse in an attempt to recapitulate some of these human pathologies. This review will summarize the three human disorders that have been linked to the mutation/dysfunction of the Na-Cl, Na-K-2Cl, and K-Cl cotransporters (i.e., Bartter's, Gitleman's, and Andermann's syndromes), examine some additional pathologies arising from genetically modified mouse models of these cotransporters including deafness, blood pressure, hyperexcitability, and epithelial transport deficit phenotypes.
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Affiliation(s)
- Kenneth B Gagnon
- Department of Anatomy and Cell Biology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
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Gamba G, Friedman PA. Thick ascending limb: the Na(+):K (+):2Cl (-) co-transporter, NKCC2, and the calcium-sensing receptor, CaSR. Pflugers Arch 2009; 458:61-76. [PMID: 18982348 PMCID: PMC3584568 DOI: 10.1007/s00424-008-0607-1] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2008] [Accepted: 10/21/2008] [Indexed: 01/12/2023]
Abstract
The thick ascending limb of Henle's loop is a nephron segment that is vital to the formation of dilute and concentrated urine. This ability is accomplished by a consortium of functionally coupled proteins consisting of the apical Na(+):K(+):2Cl(-) co-transporter, the K(+) channel, and basolateral Cl(-) channel that mediate electroneutral salt absorption. In thick ascending limbs, salt absorption is importantly regulated by the calcium-sensing receptor. Genetic or pharmacological disruption impairing the function of any of these proteins results in Bartter syndrome. The thick ascending limb is also an important site of Ca(2+) and Mg(2+) absorption. Calcium-sensing receptor activation inhibits cellular Ca(2+) absorption induced by parathyroid hormone, as well as passive paracellular Ca(2+) transport. The present review discusses these functions and their genetic and molecular regulation.
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Affiliation(s)
- Gerardo Gamba
- Molecular Physiology Unit, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
- Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Tlalpan, 14000 Mexico City, Mexico
| | - Peter A. Friedman
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
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Adachi M, Asakura Y, Sato Y, Tajima T, Nakajima T, Yamamoto T, Fujieda K. Novel SLC12A1 (NKCC2) mutations in two families with Bartter syndrome type 1. Endocr J 2007; 54:1003-7. [PMID: 17998760 DOI: 10.1507/endocrj.k06-204] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Bartter syndrome (BS) type 1, also referred to antenatal BS, is a genetic tubulopathy with hypokalemic metabolic alkalosis and prenatal onset of polyuria leading to polyhydramnios. It has been shown that BS type 1 is caused by mutations in the SLC12A1 gene encoding bumetanide-sensitive Na-K-2Cl (-) cotransporter (NKCC2). We had the opportunity to care for two unrelated Japanese patients of BS type 1 with typical manifestations including polyhydramnios, prematurity, hypokalemia, alkalosis, and infantile-onset nephrocalcinosis. Analysis of the SLC12A1 gene demonstrated four novel mutations: N117X, G257S, D792fs and N984fs. N117X mutation is expected to abolish most of the NKCC2 protein, whereas G257, which is evolutionary conserved, resides in the third transmembrane domain. The latter two frameshift mutations reside in the intra-cytoplasmic C-terminal domain, which illustrates the importance of this domain for the NKCC2 function. In conclusion, we found four novel SLC12A1 mutations in two BS type 1 patients. Development of effective therapy for hypercalciuria is mandatory to prevent nephrocalcinosis and resultant renal failure.
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Affiliation(s)
- Masanori Adachi
- Department of Endocrinology & Metabolism, Clinical Research Institute, Kanagawa Children's Medical Center, Yokohama, Japan
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Benziane B, Demaretz S, Defontaine N, Zaarour N, Cheval L, Bourgeois S, Klein C, Froissart M, Blanchard A, Paillard M, Gamba G, Houillier P, Laghmani K. NKCC2 surface expression in mammalian cells: down-regulation by novel interaction with aldolase B. J Biol Chem 2007; 282:33817-33830. [PMID: 17848580 DOI: 10.1074/jbc.m700195200] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Apical bumetanide-sensitive Na(+)-K(+)-2Cl(-) co-transporter, termed NKCC2, is the major salt transport pathway in kidney thick ascending limb. NKCC2 surface expression is subject to regulation by intracellular protein trafficking. However, the protein partners involved in the intracellular trafficking of NKCC2 remain unknown. Moreover, studies aimed at under-standing the post-translational regulation of NKCC2 have been hampered by the difficulty to express NKCC2 protein in mammalian cells. Here we were able to express NKCC2 protein in renal epithelial cells by tagging its N-terminal domain. To gain insights into the regulation of NKCC2 trafficking, we screened for interaction partners of NKCC2 with the yeast two-hybrid system, using the C-terminal tail of NKCC2 as bait. Aldolase B was identified as a dominant and novel interacting protein. Real time PCR on renal microdissected tubules demonstrated the expression of aldolase B in the thick ascending limb. Co-immunoprecipitation and co-immunolocalization experiments confirmed NKCC2-aldolase interaction in renal cells. Biotinylation assays showed that aldolase co-expression reduces NKCC2 surface expression. In the presence of aldolase substrate, fructose 1,6-bisphosphate, aldolase binding was disrupted, and aldolase co-expression had no further effect on the cell surface level of NKCC2. Finally, functional studies demonstrated that aldolase-induced down-regulation of NKCC2 at the plasma membrane was associated with a decrease in its transport activity. In summary, we identified aldolase B as a novel NKCC2 binding partner that plays a key role in the modulation of NKCC2 surface expression, thereby revealing a new regulatory mechanism governing the co-transporter intracellular trafficking. Furthermore, NKCC2 protein expression in mammalian cells and its regulation by protein-protein interactions, described here, may open new and important avenues in studying the cell biology and post-transcriptional regulation of the co-transporter.
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Affiliation(s)
- Boubacar Benziane
- INSERM U652, 75006 Paris, France; IFR58, Institut des Cordeliers, 75006 Paris, France, Universite Paris-Descartes, 75006 Paris, France
| | - Sylvie Demaretz
- INSERM U652, 75006 Paris, France; IFR58, Institut des Cordeliers, 75006 Paris, France, Universite Paris-Descartes, 75006 Paris, France
| | - Nadia Defontaine
- INSERM U652, 75006 Paris, France; IFR58, Institut des Cordeliers, 75006 Paris, France, Universite Paris-Descartes, 75006 Paris, France
| | - Nancy Zaarour
- INSERM U652, 75006 Paris, France; IFR58, Institut des Cordeliers, 75006 Paris, France, Universite Paris-Descartes, 75006 Paris, France
| | - Lydie Cheval
- IFR58, Institut des Cordeliers, 75006 Paris, France, Universite Paris-Descartes, 75006 Paris, France; CNRS-UPMC UMR7134, 75006 Paris, France
| | - Soline Bourgeois
- INSERM U652, 75006 Paris, France; IFR58, Institut des Cordeliers, 75006 Paris, France, Universite Paris-Descartes, 75006 Paris, France
| | - Christophe Klein
- IFR58, Institut des Cordeliers, 75006 Paris, France, Universite Paris-Descartes, 75006 Paris, France
| | - Marc Froissart
- INSERM U652, 75006 Paris, France; IFR58, Institut des Cordeliers, 75006 Paris, France, Universite Paris-Descartes, 75006 Paris, France; AP-HP, Departement de Physiologie, Hopital Europeen Georges Pompidou, 75015 Paris, France
| | - Anne Blanchard
- INSERM U652, 75006 Paris, France; IFR58, Institut des Cordeliers, 75006 Paris, France, Universite Paris-Descartes, 75006 Paris, France; AP-HP, Departement de Physiologie, Hopital Europeen Georges Pompidou, 75015 Paris, France
| | - Michel Paillard
- INSERM U652, 75006 Paris, France; IFR58, Institut des Cordeliers, 75006 Paris, France, Universite Paris-Descartes, 75006 Paris, France; AP-HP, Departement de Physiologie, Hopital Europeen Georges Pompidou, 75015 Paris, France
| | - Gerardo Gamba
- Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran and Instituto de Investigaciones Biomedicas, Universidad Nacional Autonoma de Mexico, Tlalpan, Mexico City 14000, Mexico
| | - Pascal Houillier
- INSERM U652, 75006 Paris, France; IFR58, Institut des Cordeliers, 75006 Paris, France, Universite Paris-Descartes, 75006 Paris, France; AP-HP, Departement de Physiologie, Hopital Europeen Georges Pompidou, 75015 Paris, France
| | - Kamel Laghmani
- INSERM U652, 75006 Paris, France; IFR58, Institut des Cordeliers, 75006 Paris, France, Universite Paris-Descartes, 75006 Paris, France.
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Cooper-Casey K, Mésen-Fainardi A, Galke-Rollins B, Llach M, Laprade B, Rodriguez C, Riondet S, Bertheau A, Byerley W. Suggestive linkage of schizophrenia to 5p13 in Costa Rica. Mol Psychiatry 2005; 10:651-6. [PMID: 15700049 DOI: 10.1038/sj.mp.4001640] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Schizophrenia afflicts roughly 1% of all people worldwide. Remarkably, despite differing cultures and environments, the expression of illness is essentially the same. Family, twin, and adoption studies identify schizophrenia as a genetically influenced disease. Linkage studies suggest many positive regions of interest, but as a complex genetic disorder most of the pathogenic loci have not yet been found. Isolated populations are commonly used to study rare Mendelian inherited diseases due to the more homogenous genetic background of the subjects and are thought to be useful for detecting linkage in complex genetic disorders such as schizophrenia. This study aims to define areas of the genome that exhibit co-inheritance with schizophrenia in one large, Mendelian-like family from the central valley of Costa Rica. The whole genome scan analysis of this pedigree, which included 11 cases of schizophrenia and schizoaffective disorder, identified a number of markers on chromosome 5p that appear to co-segregate with the disease with a maximum lod score of 2.70 at marker D5S426. Current studies include investigating additional Costa Rican pedigrees to replicate these findings and identify additional loci linked to the disease.
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Affiliation(s)
- K Cooper-Casey
- Department of Biological Chemistry, University of California, Irvine, Irvine, California, USA.
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Knepper MA, Kleyman T, Gamba G. Diuretics: Mechanisms of Action. Hypertension 2005. [DOI: 10.1016/b978-0-7216-0258-5.50152-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Mathews CA, Reus VI, Bejarano J, Escamilla MA, Fournier E, Herrera LD, Lowe TL, McInnes LA, Molina J, Ophoff RA, Raventos H, Sandkuijl LA, Service SK, Spesny M, León PE, Freimer NB. Genetic studies of neuropsychiatric disorders in Costa Rica: a model for the use of isolated populations. Psychiatr Genet 2004; 14:13-23. [PMID: 15091311 DOI: 10.1097/00041444-200403000-00003] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The importance of genetics in understanding the etiology of mental illness has become increasingly clear in recent years, as more evidence has mounted that almost all neuropsychiatric disorders have a genetic component. It has also become clear, however, that these disorders are etiologically complex, and multiple genetic and environmental factors contribute to their makeup. So far, traditional linkage mapping studies have not definitively identified specific disease genes for neuropsychiatric disorders, although some potential candidates have been identified via these methods (e.g. the dysbindin gene in schizophrenia; Straub et al., 2002; Schwab et al., 2003). For this reason, alternative approaches are being attempted, including studies in genetically isolated populations. Because isolated populations have a high degree of genetic homogeneity, their use may simplify the process of identifying disease genes in disorders where multiple genes may play a role. Several areas of Latin America contain genetically isolated populations that are well suited for the study of neuropsychiatric disorders. Genetic studies of several major psychiatric illnesses, including bipolar disorder, major depression, schizophrenia, Tourette Syndrome, alcohol dependence, attention deficit hyperactivity disorder, and obsessive-compulsive disorder, are currently underway in these regions. In this paper we highlight the studies currently being conducted by our groups in the Central Valley of Costa Rica to illustrate the potential advantages of this population for genetic studies.
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Affiliation(s)
- Carol A Mathews
- Department of Psychiatry, University of California, San Diego, La Jolla, CA 92093-0810, USA.
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Hebert SC, Mount DB, Gamba G. Molecular physiology of cation-coupled Cl- cotransport: the SLC12 family. Pflugers Arch 2004; 447:580-93. [PMID: 12739168 DOI: 10.1007/s00424-003-1066-3] [Citation(s) in RCA: 207] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2003] [Accepted: 03/27/2003] [Indexed: 01/12/2023]
Abstract
The electroneutral cation-chloride-coupled cotransporter gene family ( SLC12) was identified initially at the molecular level in fish and then in mammals. This nine-member gene family encompasses two major branches, one including two bumetanide-sensitive Na(+)-K(+)-2Cl(-) cotransporters and the thiazide-sensitive Na(+):Cl(-) cotransporter. Two of the genes in this branch ( SLC12A1 and SLC12A3), exhibit kidney-specific expression and function in renal salt reabsorption, whereas the third gene ( SLC12A2) is expressed ubiquitously and plays a key role in epithelial salt secretion and cell volume regulation. The functional characterization of both alternatively-spliced mammalian Na(+)-K(+)-2Cl(-) cotransporter isoforms and orthologs from distantly related species has generated important structure-function data. The second branch includes four genes ( SLC12A4- 7) encoding electroneutral K(+)-Cl(-) cotransporters. The relative expression level of the neuron-specific SLC12A5 and the Na(+)-K(+)-2Cl(-) cotransporter SLC12A2 appears to determine whether neurons respond to GABA with a depolarizing, excitatory response or with a hyperpolarizing, inhibitory response. The four K(+)-Cl(-) cotransporter genes are co-expressed to varying degrees in most tissues, with further roles in cell volume regulation, transepithelial salt transport, hearing, and function of the peripheral nervous system. The transported substrates of the remaining two SLC12 family members, SLC12A8 and SLC12A9, are as yet unknown. Inactivating mutations in three members of the SLC12 gene family result in Mendelian disease; Bartter syndrome type I in the case of SLC12A1, Gitelman syndrome for SLC12A3, and peripheral neuropathy in the case of SLC12A6. In addition, knockout mice for many members of this family have generated important new information regarding their respective physiological roles.
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Affiliation(s)
- Steven C Hebert
- Department of Cellular and Molecular Physiology, Yale University Medical School, 333 Cedar Street, P.O. Box 208026, SHM B147, New Haven, CT 06520-8026, USA.
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Vormfelde SV, Burckhardt G, Zirk A, Wojnowski L, Brockmöller J. Pharmacogenomics of diuretic drugs: data on rare monogenic disorders and on polymorphisms and requirements for further research. Pharmacogenomics 2003; 4:701-34. [PMID: 14596636 DOI: 10.1517/phgs.4.6.701.22817] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
This review summarizes the current status of our knowledge about the role of pharmacogenetic variation in response to diuretics and suggests future research topics for the field. Genes with a role in the pharmacokinetics of most diuretics are renal drug transporters, especially OAT1, OAT3 and OCT2 (genes SLC22A6, SLC22A8 and SLC22A2) whereas variants in carbonic anhydrase (CA), cytochrome P450 enzymes and sulfotransferases are relevant only for specific substances. Genes on the pharmacodynamic side include the primary targets of thiazide, loop, K+-sparing and aldosterone antagonistic diuretics: NCC, NKCC2, ENaC and the mineralocorticoid receptor (genes SLC12A3, SLC12A1, SCNN1A, B, G and NR3C2). Rare variants of these proteins cause Gitelman’s syndrome, Bartter’s syndrome, Liddle’s syndrome or pregnancy-induced hypertension. Polymorphisms in these and in associated proteins such as GNB3, α-adducin and angiotensin-converting enzyme (ACE) seem to be clinically relevant. In conclusion, first knowledge has evolved that efficacy of diuretic drugs may be determined by genetic polymorphisms in genes determining pharmacokinetics and pharmacodynamics of this drug class. In the future, the selection of a diuretic drug or the dosing schedules may be individually chosen based on pharmacogenetic parameters, however, many questions remain to be answered before this fantasy becomes reality.
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Affiliation(s)
- Stefan Viktor Vormfelde
- Department of Clinical Pharmacology & Department of Vegetative Physiology, Georg August University Göttingen, Robert-Koch-Str. 40, D-37075 Göttingen, Germany.
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Zelikovic I, Szargel R, Hawash A, Labay V, Hatib I, Cohen N, Nakhoul F. A novel mutation in the chloride channel gene, CLCNKB, as a cause of Gitelman and Bartter syndromes. Kidney Int 2003; 63:24-32. [PMID: 12472765 DOI: 10.1046/j.1523-1755.2003.00730.x] [Citation(s) in RCA: 135] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND Gitelman syndrome (GS) and Bartter syndrome (BS) are hereditary hypokalemic tubulopathies with distinct phenotypic features. GS has been considered a genetically homogeneous disorder caused by mutation in the gene encoding the NaCl cotransporter (TSC) of the distal convoluted tubule. In contrast, BS is caused by mutations in the genes encoding either the Na-K-2Cl cotransporter (NKCC2), the K+ channel (ROMK) or the Cl- channel (ClC-Kb) of the thick ascending limb. The purpose of this study was to examine the clinical, biochemical and genetic characteristics of a very large inbred Bedouin kindred in Northern Israel with hereditary hypokalemic tubulopathy. METHODS Twelve family members affected with hypokalemic tubulopathy, as well as 26 close relatives were clinically and biochemically evaluated. All study participants underwent genetic linkage analysis. Mutation analysis was performed in affected individuals. RESULTS Evaluation of affected family members (age range 3 to 36 years) revealed phenotypic features of both GS and classic Bartter syndrome (CBS). Features typical of GS included late age of presentation (>15 years) in 7 patients (58%), normal growth in 9 (75%), hypomagnesemia (SMg <0.7mmol/L) in 5 (42%), hypermagnesiuria (FEMg>5%) in 6 (50%) and hypocalciuria (urinary calcium/creatinine mmol/mmol <0.15) in 5 (42%). Features typical of CBS included early age of presentation (<1 year) in 3 (25%), polyuria/dehydration in 4 (33%), growth retardation in 3 (25%), hypercalciuria (urinary calcium/creatinine mmol/mmoverline>0.55) in 4 (33%) and nephrolithiasis in 1 (8%). Linkage analysis in affected patients excluded the TSC gene, SLC12A3, as the mutated gene, but demonstrated linkage to the Cl- channel gene, CLCNKB, on chromosome 1p36. Mutation analysis by direct sequencing revealed a novel homozygous missense mutation, arginine 438 to histidine (R438H), in exon 13 of CLCNKB in all patients. A restriction fragment length polymorphism (RFLP) analysis has been developed to aid in genotyping of family members. CONCLUSIONS Our findings demonstrate intrafamilial heterogeneity, namely the presence of GS and CBS phenotypes, in a kindred with the CLCNKB R438H mutation. We conclude that GS can be caused by a mutation in a gene other than SLC12A3. The exact role of the CLCNKB R438H mutation in the pathogenesis of the electrolyte and mineral abnormalities in GS and CBS remains to be established.
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Affiliation(s)
- Israel Zelikovic
- Department of Nephrology, Rambam Medical Center, Faculty of Medicine, Technion - Israel Institute of Technology, Haifa, Israel.
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Deschênes G, Feldmann D, Doucet A. [Primary molecular changes and secondary biological problems in Bartter and Gitelman syndrome]. Arch Pediatr 2002; 9:406-16. [PMID: 11998428 DOI: 10.1016/s0929-693x(01)00801-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Bartter syndrome and Gitelman syndrome are primary hereditary diseases characterized by hypokaliemia, alkalosis, hypertrophy of the juxtaglomerular complex with secondary hyperaldoteronism and normal blood pressure. They result from molecular disorders leading to a defect of sodium reabsorption in respectively the Henle's loop and the distal convoluted tubule. Biological adaptations of downstream tubular segments, i.e. distal convoluted tubule and collecting duct, are responsible for hypokaliemia, alkalosis, renin-aldosterone activation, prostaglandins hypersecretion and dysregulation of the urinary excretion of calcium and magnesium, illustrating the close integration of the regulation of different solutes in the distal tubular structures.
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Affiliation(s)
- G Deschênes
- Service de néphrologie pédiatrique, hôpital Armand-Trousseau, 26, avenue du Docteur-Arnold-Netter, 75012 Paris, France.
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Ernst LM, Parkash V. Placental pathology in fetal bartter syndrome. Pediatr Dev Pathol 2002; 5:76-9. [PMID: 11815871 DOI: 10.1007/s10024-001-0092-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2001] [Accepted: 08/15/2001] [Indexed: 10/26/2022]
Abstract
Bartter syndrome, which presents clinically with polyuria, urinary potassium loss, hypokalemia, hypercalciuria, and alkalosis, is an autosomal recessive disorder with mutations in genes encoding the Na-K-2Cl cotransporter, the chloride channel CLC-NKB, and the potassium channel ROMK. Prenatal diagnosis of Bartter syndrome is now possible; however, there are no reports of the placental pathology associated with fetal Bartter syndrome. We present the placental pathologic findings in two siblings with fetal Bartter syndrome. Both pregnancies were complicated by polyhydramnios and preterm delivery. The first pregnancy delivered at 30 weeks, and Bartter syndrome was diagnosed in the perinatal period. The subsequent pregnancy required periodic therapeutic amniocentesis secondary to massive polyhydramnios and delivered at 32 weeks gestation. The suspicion of fetal Bartter syndrome was very high in this second pregnancy, and the infant was confirmed to have Bartter syndrome subsequently. Both placentas were large for gestational age, weighing greater than the 95th percentile. Microscopic examination showed extensive subtrophoblastic basement membrane mineralization (special stains positive for iron and calcium) in the chorionic villi. This striking finding was present in both placentas. Subtrophoblastic mineralization has been described in the literature in placentas of fetuses with abnormalities including anencephaly, trisomy 21, and other congenital abnormalities; however, it has also been described in normal pregnancies. Mechanisms of calcification in the placenta are not well understood, but these striking cases suggest that defects in fetal renal excretion of ions can lead to dystrophic calcification within the placenta, particularly in a subtrophoblastic pattern.
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Affiliation(s)
- Linda M Ernst
- Department of Anatomic Pathology, Yale University School of Medicine, PO Box 208070, New Haven, CT 06520, USA
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Shaer AJ. Inherited primary renal tubular hypokalemic alkalosis: a review of Gitelman and Bartter syndromes. Am J Med Sci 2001; 322:316-32. [PMID: 11780689 DOI: 10.1097/00000441-200112000-00004] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Inherited hypokalemic metabolic alkalosis, or Bartter syndrome, comprises several closely related disorders of renal tubular electrolyte transport. Recent advances in the field of molecular genetics have demonstrated that there are four genetically distinct abnormalities, which result from mutations in renal electrolyte transporters and channels. Neonatal Bartter syndrome affects neonates and is characterized by polyhydramnios, premature delivery, severe electrolyte derangements, growth retardation, and hypercalciuria leading to nephrocalcinosis. It may be caused by a mutation in the gene encoding the Na-K-2Cl cotransporter (NKCC2) or the outwardly rectifying potassium channel (ROMK), a regulator of NKCC2. Classic Bartter syndrome is due to a mutation in the gene encoding the chloride channel (CLCNKB), also a regulator of NKCC2, and typically presents in infancy or early childhood with failure to thrive. Nephrocalcinosis is typically absent despite hypercalciuria. The hypocalciuric, hypomagnesemic variant of Bartter syndrome (Gitelman syndrome), presents in early adulthood with predominantly musculoskeletal symptoms and is due to mutations in the gene encoding the Na-Cl cotransporter (NCCT). Even though our understanding of these disorders has been greatly advanced by these discoveries, the pathophysiology remains to be completely defined. Genotype-phenotype correlations among the four disorders are quite variable and continue to be studied. A comprehensive review of Bartter and Gitelman syndromes will be provided here.
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Affiliation(s)
- A J Shaer
- Division of Nephrology, Medical University of South Carolina, Charleston 29425, USA.
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Abstract
Cl- transport in the loop of Henle is responsible for reclamation of 25-40% of the filtered NaCl load and for the formation of dilute urine. Our understanding of the physiologic and molecular mechanisms responsible for Cl- reabsorption in both the thin ascending limb and thick ascending limb of Henle's loop has increased greatly over the last decade. Plasma membrane Cl- channels are known to play an integral role in transcellular Cl- transport in both the thin and thick ascending limbs. This review focuses on the functional characteristics and molecular identities of these Cl- channels, as well as the role of these channels in the pathophysiology of disease.
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Affiliation(s)
- W B Reeves
- Division of Nephrology, University of Arkansas College of Medicine and the John L McClellan Veterans Hospital, Little Rock, Arkansas 72205, USA.
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Konrad M, Vollmer M, Lemmink HH, VAN DEN Heuvel LPWJ, Jeck N, Vargas-Poussou R, Lakings A, Ruf R, Deschênes G, Antignac C, Guay-Woodford L, Knoers NVAM, Seyberth HW, Feldmann D, Hildebrandt F. Mutations in the chloride channel gene CLCNKB as a cause of classic Bartter syndrome. J Am Soc Nephrol 2000; 11:1449-1459. [PMID: 10906158 DOI: 10.1681/asn.v1181449] [Citation(s) in RCA: 225] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
ABSTRACT.: Inherited hypokalemic renal tubulopathies are differentiated into at least three clinical subtypes: (1) the Gitelman variant of Bartter syndrome (GS); (2) hyperprostaglandin E syndrome, the antenatal variant of Bartter syndrome (HPS/aBS); and (3) the classic Bartter syndrome (cBS). Hypokalemic metabolic alkalosis and renal salt wasting are the common characteristics of all three subtypes. Hypocalciuria and hypomagnesemia are specific clinical features of Gitelman syndrome, while HPS/aBS is a life-threatening disorder of the newborn with polyhydramnios, premature delivery, hyposthenuria, and nephrocalcinosis. The Gitelman variant is uniformly caused by mutations in the gene for the thiazide-sensitive NaCl-cotransporter NCCT (SLC12A3) of the distal tubule, while HPS/aBS is caused by mutations in the gene for either the furosemide-sensitive NaK-2Cl-cotransporter NKCC2 (SLC12A1) or the inwardly rectifying potassium channel ROMK (KCNJ1). Recently, mutations in a basolateral chloride channel CLC-Kb (CLCNKB) have been described in a subset of patients with a Bartter-like phenotype typically lacking nephrocalcinosis. In this study, the screening for CLCNKB mutations showed 20 different mutations in the affected children from 30 families. The clinical characterization revealed a highly variable phenotype ranging from episodes of severe volume depletion and hypokalemia during the neonatal period to almost asymptomatic patients diagnosed during adolescence. This study adds 16 novel mutations to the nine already described, providing further evidence that mutations in the gene for the basolateral chloride channel CLC-Kb are the molecular basis of classic Bartter syndrome. Interestingly, the phenotype elicited by CLCNKB mutations occasionally includes HPS/aBS, as well as a Gitelman-like phenotype.
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Affiliation(s)
- Martin Konrad
- Department of Pediatrics, Philipps University, Marburg, Germany
| | - Martin Vollmer
- Department of Pediatrics, Albert Ludwigs University of Freiburg, Germany
| | - Henny H Lemmink
- Departments of Pediatrics and Human Genetics, University Hospital Nijmegen, The Netherlands
| | | | - Nikola Jeck
- Department of Pediatrics, Philipps University, Marburg, Germany
| | - Rosa Vargas-Poussou
- Institut National de la Santé et de la Recherche Médicale U423, Necker Hospital, University of Paris, France
| | - Alicia Lakings
- Departments of Medicine and Pediatrics, University of Alabama at Birmingham, Alabama
| | - Rainer Ruf
- Department of Pediatrics, Albert Ludwigs University of Freiburg, Germany
| | - Georges Deschênes
- Departments of Biochemistry and Pediatric Nephrology, Armand-Trousseau Hospital, Paris, France
| | - Corinne Antignac
- Institut National de la Santé et de la Recherche Médicale U423, Necker Hospital, University of Paris, France
| | - Lisa Guay-Woodford
- Departments of Medicine and Pediatrics, University of Alabama at Birmingham, Alabama
| | - Nine V A M Knoers
- Departments of Pediatrics and Human Genetics, University Hospital Nijmegen, The Netherlands
| | | | - Delphine Feldmann
- Departments of Biochemistry and Pediatric Nephrology, Armand-Trousseau Hospital, Paris, France
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Hamilton KL, Butt AG. The molecular basis of renal tubular transport disorders. Comp Biochem Physiol A Mol Integr Physiol 2000; 126:305-21. [PMID: 10964027 DOI: 10.1016/s1095-6433(00)00214-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Sodium and water homeostasis are key to the survival of organisms. Reabsorption of sodium and water occurs throughout the tubule structure of the nephron, the basic functional unit of the kidney, by various transport mechanisms. Altered transport protein function can lead to renal tubular disorders resulting in metabolic alkalosis, hypokalemia, hypertension, and decreased capacity to concentrate urine, for instance. However, recent advances in molecular physiology, molecular genetics and expression cloning systems have aided in unraveling the molecular basis of some renal tubular disorders. This review will examine the molecular basis of Bartter's syndrome, Gitelman's syndrome, Liddle's syndrome, and autosomal nephrogenic diabetes insipidus. An understanding of the molecular basis of these disorders of the human kidney can give us a better understanding of basic renal function of lower mammals and other vertebrates.
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Affiliation(s)
- K L Hamilton
- Department of Physiology, School of Medical Sciences, University of Otago, P.O. Box 913, Dunedin, New Zealand.
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Benigno V, Canonica CS, Bettinelli A, von Vigier RO, Truttmann AC, Bianchetti MG. Hypomagnesaemia-hypercalciuria-nephrocalcinosis: a report of nine cases and a review. Nephrol Dial Transplant 2000; 15:605-10. [PMID: 10809799 DOI: 10.1093/ndt/15.5.605] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND The cardinal characteristics of primary hypomagnesaemia-hypercalciuria-nephrocalcinosis include renal magnesium wasting, marked hypercalciuria, renal stones, nephrocalcinosis, a tendency towards chronic renal insufficiency and sometimes even ocular abnormalities or hearing impairment. METHODS As very few patients with this syndrome have been described, we provide information on nine patients on follow-up at our institutions and review the 42 cases reported in the literature (33 females and 18 males). RESULTS Urinary tract infections, polyuria-polydipsia, renal stones and tetanic convulsions were the main clinical findings at diagnosis. The clinical course was highly variable; renal failure was often reported. The concomitant occurrence of ocular involvement or hearing impairment was reported in a large subset of patients. Parental consanguinity was noted in some families. CONCLUSIONS The results indicate an autosomal recessive inheritance. The diagnosis of primary hypomagnesaemia-hypercalciuria-nephrocalcinosis deserves consideration in any patient with nephrocalcinosis and hypercalciuria.
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Affiliation(s)
- V Benigno
- Department of Pediatrics, University of Bern, Switzerland
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Deliyska B, Lazarov V, Minkova V, Nikolov D, Tishkov I. Association of Bartter's syndrome with vasculitis. Nephrol Dial Transplant 2000; 15:102-3. [PMID: 10607776 DOI: 10.1093/ndt/15.1.102] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- B Deliyska
- Clinical Center of Nephrology and Department of Pathology, Medical University, Sofia, Bulgaria
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Abraham MR, Jahangir A, Alekseev AE, Terzic A. Channelopathies of inwardly rectifying potassium channels. FASEB J 1999; 13:1901-10. [PMID: 10544173 DOI: 10.1096/fasebj.13.14.1901] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Mutations in genes encoding ion channels have increasingly been identified to cause disease conditions collectively termed channelopathies. Recognizing the molecular basis of an ion channel disease has provided new opportunities for screening, early diagnosis, and therapy of such conditions. This synopsis provides an overview of progress in the identification of molecular defects in inwardly rectifying potassium (Kir) channels. Structurally and functionally distinct from other channel families, Kir channels are ubiquitously expressed and serve functions as diverse as regulation of resting membrane potential, maintenance of K(+) homeostasis, control of heart rate, and hormone secretion. In humans, persistent hyperinsulinemic hypoglycemia of infancy, a disorder affecting the function of pancreatic beta cells, and Bartter's syndrome, characterized by hypokalemic alkalosis, hypercalciuria, increased serum aldosterone, and plasma renin activity, are the two major diseases linked so far to mutations in a Kir channel or associated protein. In addition, the weaver phenotype, a neurological disorder in mice, has also been associated with mutations in a Kir channel subtype. Further genetic linkage analysis and full understanding of the consequence that a defect in a Kir channel would have on disease pathogenesis are among the priorities in this emerging field of molecular medicine.
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Affiliation(s)
- M R Abraham
- Division of Cardiovascular Diseases, Department of Internal Medicine, Mayo Clinic, Mayo Foundation, Rochester, Minnesota 55905, USA
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Abstract
The successful merging of modern molecular genetics with basic renal physiology is exemplified by the recent description of the molecular basis of two classic diseases of clinical nephrology; Bartter's and Gitelman's syndromes of inherited hypokalemic alkalosis. Mutations in four different genes have been identified, each of which causes hypokalemic alkalosis, salt wasting and hypotension. These genetic studies have greatly advanced our understanding of renal physiology.
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Affiliation(s)
- D B Simon
- Howard Hughes Medical Institute, Department of Medicine, Boyer Center for Molecular Medicine, Yale University School of Medicine, New Haven, Connecticut 06510, USA.
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