1
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Nickerson AJ, Mutchler SM, Sheng S, Cox NA, Ray EC, Kashlan OB, Carattino MD, Marciszyn AL, Winfrey A, Gingras S, Kirabo A, Hughey RP, Kleyman TR. Mice lacking γENaC palmitoylation sites maintain benzamil-sensitive Na+ transport despite reduced channel activity. JCI Insight 2023; 8:e172051. [PMID: 37707951 PMCID: PMC10721255 DOI: 10.1172/jci.insight.172051] [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: 05/08/2023] [Accepted: 09/12/2023] [Indexed: 09/16/2023] Open
Abstract
Epithelial Na+ channels (ENaCs) control extracellular fluid volume by facilitating Na+ absorption across transporting epithelia. In vitro studies showed that Cys-palmitoylation of the γENaC subunit is a major regulator of channel activity. We tested whether γ subunit palmitoylation sites are necessary for channel function in vivo by generating mice lacking the palmitoylated cysteines (γC33A,C41A) using CRISPR/Cas9 technology. ENaCs in dissected kidney tubules from γC33A,C41A mice had reduced open probability compared with wild-type (WT) littermates maintained on either standard or Na+-deficient diets. Male mutant mice also had higher aldosterone levels than WT littermates following Na+ restriction. However, γC33A,C41A mice did not have reduced amiloride-sensitive Na+ currents in the distal colon or benzamil-induced natriuresis compared to WT mice. We identified a second, larger conductance cation channel in the distal nephron with biophysical properties distinct from ENaC. The activity of this channel was higher in Na+-restricted γC33A,C41A versus WT mice and was blocked by benzamil, providing a possible compensatory mechanism for reduced prototypic ENaC function. We conclude that γ subunit palmitoylation sites are required for prototypic ENaC activity in vivo but are not necessary for amiloride/benzamil-sensitive Na+ transport in the distal nephron or colon.
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Affiliation(s)
| | | | | | | | | | - Ossama B. Kashlan
- Department of Medicine
- Department of Computational and Systems Biology
| | | | | | | | - Sebastien Gingras
- Department of Immunology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Annet Kirabo
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | | | - Thomas R. Kleyman
- Department of Medicine
- Department of Cell Biology, and
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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2
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Guo W, Ji P, Xie Y. Genetic Diagnosis and Treatment of Inherited Renal Tubular Acidosis. KIDNEY DISEASES (BASEL, SWITZERLAND) 2023; 9:371-383. [PMID: 37901710 PMCID: PMC10601937 DOI: 10.1159/000531556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 06/12/2023] [Indexed: 10/31/2023]
Abstract
Background Renal tubular acidosis (RTA) is caused by various disruptions to the secretion of H+ by distal renal tubules and/or dysfunctional reabsorption of HCO3- by proximal renal tubules, which causes renal acidification dysfunction, ultimately leading to a clinical syndrome characterized by hyperchloremic metabolic acidosis with a normal anion gap. With the development of molecular genetics and gene sequencing technology, inherited RTA has also attracted attention, and an increasing number of RTA-related pathogenic genes have been discovered and reported. Summary This paper focuses on the latest progress in the research of inherited RTA and systematically reviews the pathogenic genes, protein functions, clinical manifestations, internal relationship between genotypes and clinical phenotypes, diagnostic clues, differential diagnosis, and treatment strategies associated with inherited RTA. This paper aims to deepen the understanding of inherited RTA and reduce the missed diagnosis and misdiagnosis of RTA. Key Messages This review systematically summarizes the pathogenic genes, pathophysiological mechanisms, differential diagnosis, and treatment of different types of inherited RTA, which has good clinical value for guiding the diagnosis and treatment of inherited RTA.
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Affiliation(s)
- Wenkai Guo
- Department of Nephrology, First Medical Center of Chinese PLA General Hospital, Chinese PLA Institute of Nephrology, State Key Laboratory of Kidney Diseases, National Clinical Research Center for Kidney Diseases, Beijing, China
- School of Medicine, Nankai University, Tianjin, China
| | - Pengcheng Ji
- Department of Nephrology, First Medical Center of Chinese PLA General Hospital, Chinese PLA Institute of Nephrology, State Key Laboratory of Kidney Diseases, National Clinical Research Center for Kidney Diseases, Beijing, China
| | - Yuansheng Xie
- Department of Nephrology, First Medical Center of Chinese PLA General Hospital, Chinese PLA Institute of Nephrology, State Key Laboratory of Kidney Diseases, National Clinical Research Center for Kidney Diseases, Beijing, China
- School of Medicine, Nankai University, Tianjin, China
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3
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Barforoshi S, Thangathurai J, Khakpour H, Shah S. Brugada syndrome uncovered in patient with pseudohypoaldosteronism due to hyperkalaemia. BMJ Case Rep 2023; 16:e255111. [PMID: 37399349 DOI: 10.1136/bcr-2023-255111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/05/2023] Open
Abstract
Brugada syndrome is a rare sodium channelopathy that predisposes to an increased risk of malignant arrythmias and sudden cardiac death. Previous studies have reported that metabolic disturbances can uncover a Brugada ECG pattern. Given the risk of malignant arrhythmias, it is important to correctly diagnose and treat Brugada syndrome. We report a case of Brugada syndrome uncovered by hyperkalaemia precipitated in a patient with pseudohypoaldosteronism.
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Affiliation(s)
| | - Jenica Thangathurai
- Division of Cardiology, Department of Medicine, Harbor-UCLA Medical Center, Torrance, California, USA
| | - Houman Khakpour
- Cardiac Arrhythmia Center, UCLA Health System, University of California Los Angeles David Geffen School of Medicine, Los Angeles, California, USA
| | - Sonia Shah
- Division of Cardiology, Department of Medicine, Harbor-UCLA Medical Center, Torrance, California, USA
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4
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Gao Z, Sun J, Cai C, Gong X, Ma L. Pseudohypoaldosteronism type 1b in fraternal twins of a Chinese family: report of two cases and literature review. ARCHIVES OF ENDOCRINOLOGY AND METABOLISM 2023; 67:e000620. [PMID: 37252702 PMCID: PMC10665068 DOI: 10.20945/2359-3997000000620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 08/21/2022] [Indexed: 05/31/2023]
Abstract
Here, we report the clinical observations of two Chinese fraternal twins who presented with severe dehydration, poor feeding, and absence of stimuli responses within a few days of birth. Trio clinical exome sequencing of the family identified compound heterozygous intronic variants (c.1439+1G>C and c.875+1G>A ) in SCNN1A gene in these two patients. Sanger sequencing results showed that the c.1439+1G>C variant was inherited from the mother, and c.875+1G>A from the father, rarely reported in pseudohypoaldosteronism type 1 with sodium epithelial channel destruction (PHA1b) patients. Case 2 received timely symptomatic treatment and management after obtaining these results, which improved the clinical crisis. Our results suggest that the compound heterozygous splicing variants in SCNN1A were responsible for PHA1b in these Chinese fraternal twins. This finding extends the knowledge of the variant spectrum in PHA1b patients and highlights the application of exome sequencing in critically ill newborns. Finally, we discuss supportive case management, particularly in maintaining blood potassium concentration.
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Affiliation(s)
- Zhen Gao
- Department of Neonatology, Shanghai Children's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Jingjing Sun
- Department of Neonatology, Shanghai Children's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- NHC Key Laboratory of Medical Embryogenesis and Developmental Molecular Biology & Shanghai Key Laboratory of Embryo and Reproduction Engineering, Shanghai, China
| | - Cheng Cai
- Department of Neonatology, Shanghai Children's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- NHC Key Laboratory of Medical Embryogenesis and Developmental Molecular Biology & Shanghai Key Laboratory of Embryo and Reproduction Engineering, Shanghai, China
| | - Xiaohui Gong
- Department of Neonatology, Shanghai Children's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- NHC Key Laboratory of Medical Embryogenesis and Developmental Molecular Biology & Shanghai Key Laboratory of Embryo and Reproduction Engineering, Shanghai, China
| | - Li Ma
- Department of Neonatology, Shanghai Children's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- NHC Key Laboratory of Medical Embryogenesis and Developmental Molecular Biology & Shanghai Key Laboratory of Embryo and Reproduction Engineering, Shanghai, China,
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5
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Hasenmajer V, Ferrigno R, Minnetti M, Pellegrini B, Isidori AM, Lenzi A, Salerno M, Cappa M, Chan L, De Martino MC, Savage MO. Rare forms of genetic paediatric adrenal insufficiency: Excluding congenital adrenal hyperplasia. Rev Endocr Metab Disord 2023; 24:345-363. [PMID: 36763264 PMCID: PMC10023752 DOI: 10.1007/s11154-023-09784-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/03/2023] [Indexed: 02/11/2023]
Abstract
Adrenal insufficiency (AI) is a severe endocrine disorder characterized by insufficient glucocorticoid (GC) and/or mineralocorticoid (MC) secretion by the adrenal glands, due to impaired adrenal function (primary adrenal insufficiency, PAI) or to insufficient adrenal stimulation by pituitary ACTH (secondary adrenal insufficiency, SAI) or tertiary adrenal insufficiency due to hypothalamic dysfunction. In this review, we describe rare genetic causes of PAI with isolated GC or combined GC and MC deficiencies and we also describe rare syndromes of isolated MC deficiency. In children, the most frequent cause of PAI is congenital adrenal hyperplasia (CAH), a group of adrenal disorders related to steroidogenic enzyme deficiencies, which will not be included in this review. Less frequently, several rare diseases can cause PAI, either affecting exclusively the adrenal glands or with systemic involvement. The diagnosis of these diseases is often challenging, due to the heterogeneity of their clinical presentation and to their rarity. Therefore, the current review aims to provide an overview on these rare genetic forms of paediatric PAI, offering a review of genetic and clinical features and a summary of diagnostic and therapeutic approaches, promoting awareness among practitioners, and favoring early diagnosis and optimal clinical management in suspect cases.
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Affiliation(s)
- Valeria Hasenmajer
- Department of Experimental Medicine, Sapienza University of Rome, Rome, Italy
| | - Rosario Ferrigno
- UOSD Auxology and Endocrinology, Department of Pediatric, AORN Santobono-Pausilipon, Naples, Italy
| | - Marianna Minnetti
- Department of Experimental Medicine, Sapienza University of Rome, Rome, Italy
| | - Bianca Pellegrini
- Dipartimento Di Medicina Clinica E Chirurgia, Federico II University, Naples, Italy
| | - Andrea M Isidori
- Department of Experimental Medicine, Sapienza University of Rome, Rome, Italy
| | - Andrea Lenzi
- Department of Experimental Medicine, Sapienza University of Rome, Rome, Italy
| | | | - Marco Cappa
- Endocrinology Unit, Pediatric University Department, Bambino Gesù Children's Hospital, Rome, Italy
| | - Li Chan
- Endocrinology Centre, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, Charterhouse Square, London, EC1M 6BQ, UK
| | | | - Martin O Savage
- Endocrinology Centre, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, Charterhouse Square, London, EC1M 6BQ, UK.
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6
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Nanda PM, Sharma R, Jain V. Successful Management of Systemic Pseudohypoaldosteronism Type 1 in an Infant. Indian Pediatr 2023. [DOI: 10.1007/s13312-023-2815-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023]
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7
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Abdalla A, Alhassan MA, Tawfeeg R, Sanad A, Tawamie H, Abdullah M. Systemic pseudohypoaldosteronism-1 with episodic dyslipidemia in a Sudanese child. Endocrinol Diabetes Metab Case Rep 2021; 2021:EDM210010. [PMID: 34165441 PMCID: PMC8240716 DOI: 10.1530/edm-21-0010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 05/25/2021] [Indexed: 11/08/2022] Open
Abstract
SUMMARY Systemic pseudohypoaldosteronism type 1 (PHA1) is a rare genetic syndrome of tissue unresponsiveness to aldosterone caused by mutations affecting the epithelial Na channel (ENaC). The classical presentation is life-threatening neonatal/infantile salt-losing crises that mimic congenital adrenal hyperplasia (CAH). Consistently, extra-renal manifestations, including respiratory symptoms that resemble cystic fibrosis, are well reported. Clinical diagnosis is made by the presence of hyponatremia, hyperkalemia, metabolic acidosis, respiratory symptoms, evidence of high renal and extra-renal salt loss in addition to high plasma renin and aldosterone levels. We herein report a novel manifestation of PHA1: episodic dyslipidemia in a 7-month-old Sudanese boy that occurred during the salt-losing crises. Whole exome sequencing of the patient revealed one homozygous missense variant c.1636G>A p.(Asp546Asn) in the SCNN1B gene, confirming our clinical and laboratory findings that were compatible with PHA1. This report aims to highlight the possible explanation of dyslipidemia in PHA1 and its expected consequences in the long term. LEARNING POINTS A child presenting with features that mimic salt-losing congenital adrenal hyperplasia (CAH) crises that do not respond to glucocorticoid and mineralocorticoid therapy should alert the pediatricians to the possibility of end-organ resistance to aldosterone. Pseudohypoaldosteronism type 1 (PHA1) can be diagnosed even in the absence of advanced laboratory investigations. To our knowledge, this is the first case of systemic PHA1 to have a documented episodic dyslipidemia (primarily as marked hypertriglyceridemia).
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Affiliation(s)
- Asmahan Abdalla
- Department of Pediatric Endocrinologist, Gaafar Ibn Auf Children’s Tertiary Hospital, Khartoum, Sudan
| | | | - Reem Tawfeeg
- Department of Pediatric Respirologist, Elswaidi Charity Hospital, Khartoum, Sudan
| | - Ayman Sanad
- Department of Pediatrics, University of Shendi, Shendi, Sudan
| | - Hasan Tawamie
- Clinical Lab Operations at Centogene Laboratory, Rostock, Mecklenburg-Vorpommern, Germany
| | - Mohamed Abdullah
- Departmentof Pediatric Endocrinology, Faculty of Medicine, University of Khartoum, Khartoum, Sudan
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8
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Conversano E, Romano S, Taddio A, Faletra F, Zanon D, Barbi E, Pennesi M. When salt is needed to grow: Answers. Pediatr Nephrol 2021; 36:1131-1132. [PMID: 32778955 DOI: 10.1007/s00467-020-04647-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 06/02/2020] [Indexed: 11/25/2022]
Affiliation(s)
- Ester Conversano
- Department of Medicine, Surgery, and Health Sciences, University of Trieste, Trieste, Italy
| | - Sara Romano
- Department of Medicine, Surgery, and Health Sciences, University of Trieste, Trieste, Italy.
| | - Andrea Taddio
- Department of Medicine, Surgery, and Health Sciences, University of Trieste, Trieste, Italy
- Paediatric Department, Institute for Maternal and Child Health-IRCCS "Burlo Garofolo", Trieste, Italy
| | - Flavio Faletra
- Genetic Department, Institute for Maternal and Child Health-IRCCS "Burlo Garofolo", Trieste, Italy
| | - Davide Zanon
- Pharmacy and Clinical Pharmacology Department, Institute for Maternal and Child Health-IRCCS "Burlo Garofolo", Trieste, Italy
| | - Egidio Barbi
- Department of Medicine, Surgery, and Health Sciences, University of Trieste, Trieste, Italy
- Paediatric Department, Institute for Maternal and Child Health-IRCCS "Burlo Garofolo", Trieste, Italy
| | - Marco Pennesi
- Paediatric Department, Institute for Maternal and Child Health-IRCCS "Burlo Garofolo", Trieste, Italy
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9
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Kodo K, Goto S, Katsumi Y. Secondary Pseudohypoaldosteronism Associated With Mild Hydronephrosis in a Newborn. Cureus 2021; 13:e13462. [PMID: 33777551 PMCID: PMC7985187 DOI: 10.7759/cureus.13462] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Neonatal hyponatremia with hyperkalemia is a rare but potentially life-threatening occurrence. Aldosterone deficiency secondary to congenital adrenal hyperplasia (CAH) is often suspected in these cases, although it is not easy to accurately diagnose it initially. We report the case of a 12-day-old female infant presenting with poor sucking, hyperkalemia, and hyponatremia. Plasma renin activity (PRA) and aldosterone levels were markedly elevated, and mild hydronephrosis [Society for Fetal Urology (SFU) grade 1] was noted. We then suspected secondary pseudohypoaldosteronism (S-PHA); however, her serum potassium level remained elevated despite sodium infusion. Because we could not rule out a diagnosis of adrenal insufficiency caused by CAH, we cautiously initiated hydrocortisone. After reviewing the results of a mass screening test and a urine steroid profile analysis, adrenal diseases were ruled out and we diagnosed the patient with S-PHA. This report aims to illustrate that mild hydronephrosis can cause S-PHA by inducing renal tubular resistance to aldosterone. Because the symptoms of S-PHA are similar to those of CAH, we recognize that further studies are needed to clarify their differences.
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Affiliation(s)
- Kazuki Kodo
- Department of Pediatrics, Saiseikai Kyoto Hospital, Kyoto, JPN
| | - Sachiko Goto
- Department of Pediatrics, Saiseikai Kyoto Hospital, Kyoto, JPN
| | - Yoshiki Katsumi
- Department of Pediatrics, Saiseikai Kyoto Hospital, Kyoto, JPN
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10
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Ayasse N, Berg P, Leipziger J, Sørensen MV. ENaC expression correlates with the acute furosemide-induced K + excretion. Physiol Rep 2021; 9:e14668. [PMID: 33410279 PMCID: PMC7788322 DOI: 10.14814/phy2.14668] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 10/27/2020] [Accepted: 10/28/2020] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND In the aldosterone-sensitive distal nephron (ASDN), epithelial sodium channel (ENaC)-mediated Na+ absorption drives K+ excretion. K+ excretion depends on the delivery of Na+ to the ASDN and molecularly activated ENaC. Furosemide is known as a K+ wasting diuretic as it greatly enhances Na+ delivery to the ASDN. Here, we studied the magnitude of acute furosemide-induced kaliuresis under various states of basal molecular ENaC activity. METHODS C57/Bl6J mice were subjected to different dietary regimens that regulate molecular ENaC expression and activity levels. The animals were anesthetized and bladder-catheterized. Diuresis was continuously measured before and after administration of furosemide (2 µg/g BW) or benzamil (0.2 µg/g BW). Flame photometry was used to measure urinary [Na+ ] and [K+ ]. The kidneys were harvested and, subsequently, ENaC expression and cleavage activation were determined by semiquantitative western blotting. RESULTS A low K+ and a high Na+ diet markedly suppressed ENaC protein expression, cleavage activation, and furosemide-induced kaliuresis. In contrast, furosemide-induced kaliuresis was greatly enhanced in animals fed a high K+ or low Na+ diet, conditions with increased ENaC expression. The furosemide-induced diuresis was similar in all dietary groups. CONCLUSION Acute furosemide-induced kaliuresis differs greatly and depends on the a priori molecular expression level of ENaC. Remarkably, it can be even absent in animals fed a high Na+ diet, despite a marked increase of tubular flow and urinary Na+ excretion. This study provides auxiliary evidence that acute ENaC-dependent K+ excretion requires both Na+ as substrate and molecular activation of ENaC.
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Affiliation(s)
- Niklas Ayasse
- Department of Biomedicine, PhysiologyAarhus UniversityAarhus CDenmark
| | - Peder Berg
- Department of Biomedicine, PhysiologyAarhus UniversityAarhus CDenmark
| | - Jens Leipziger
- Department of Biomedicine, PhysiologyAarhus UniversityAarhus CDenmark
- Aarhus Institute of Advanced StudiesAarhus UniversityAarhus CDenmark
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11
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Goda T, Komatsu H, Nozu K, Nakajima H. An infantile case of pseudohypoaldosteronism type 1 (PHA1) caused by a novel mutation of NR3C2. Clin Pediatr Endocrinol 2020; 29:127-130. [PMID: 32694891 PMCID: PMC7348633 DOI: 10.1297/cpe.29.127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 05/21/2020] [Indexed: 11/23/2022] Open
Affiliation(s)
- Takeshi Goda
- Department of Pediatrics, Kyoto Chubu Medical Center, Kyoto, Japan.,Department of Pediatrics, National Hospital Organization Maizuru Medical Center, Kyoto, Japan
| | - Hiroshi Komatsu
- Department of Pediatrics, National Hospital Organization Maizuru Medical Center, Kyoto, Japan
| | - Kandai Nozu
- Department of Pediatrics, Kobe University Graduate School of Medicine, Hyogo, Japan
| | - Hisakazu Nakajima
- Department of Pediatrics, National Hospital Organization Maizuru Medical Center, Kyoto, Japan.,Department of Pediatrics, North Medical Center Kyoto Prefectural University of Medicine, Kyoto, Japan
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12
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Yonker LM, Hawley MH, Moschovis PP, Lu M, Kinane TB. Recognizing genetic disease: A key aspect of pediatric pulmonary care. Pediatr Pulmonol 2020; 55:1794-1809. [PMID: 32533909 PMCID: PMC7384240 DOI: 10.1002/ppul.24706] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 02/12/2020] [Indexed: 12/19/2022]
Abstract
Advancement in technology has improved recognition of genetic etiologies of disease, which has impacted diagnosis and management of rare disease patients in the pediatric pulmonary clinic. This review provides an overview of genetic conditions that are likely to present with pulmonary features and require extensive care by the pediatric pulmonologist. Increased familiarity with these conditions allows for improved care of these patients by reducing time to diagnosis, tailoring management, and prompting further investigation into these disorders.
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Affiliation(s)
- Lael M Yonker
- Pulmonary Division, Massachusetts General Hospital for Children, Boston, Massachusetts.,Department of Pediatrics, Harvard Medical School, Boston, Massachusetts
| | - Megan H Hawley
- Pulmonary Division, Massachusetts General Hospital for Children, Boston, Massachusetts.,Laboratory for Molecular Medicine, Partners HealthCare Personalized Medicine, Cambridge, Massachusetts
| | - Peter P Moschovis
- Pulmonary Division, Massachusetts General Hospital for Children, Boston, Massachusetts.,Department of Pediatrics, Harvard Medical School, Boston, Massachusetts
| | - Mengdi Lu
- Pulmonary Division, Massachusetts General Hospital for Children, Boston, Massachusetts.,Department of Pediatrics, Harvard Medical School, Boston, Massachusetts
| | - T Bernard Kinane
- Pulmonary Division, Massachusetts General Hospital for Children, Boston, Massachusetts.,Department of Pediatrics, Harvard Medical School, Boston, Massachusetts
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13
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Adachi M, Tajima T, Muroya K. Dietary potassium restriction attenuates urinary sodium wasting in the generalized form of pseudohypoaldosteronism type 1. CEN Case Rep 2020; 9:133-137. [PMID: 31900739 DOI: 10.1007/s13730-019-00441-0] [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: 08/21/2019] [Accepted: 12/15/2019] [Indexed: 10/25/2022] Open
Abstract
Owing to its rarity and severe nature, the treatment for generalized pseudohypoaldosteronism type 1 (PHA1), a genetic disorder in the epithelial sodium channel (ENaC), is exclusively experience-based. In particular, the usefulness of dietary potassium restriction in PHA1 remains unclear with the absence of theoretical background to elucidate its utility. First, we demonstrated the effect of potassium restriction in a 13-month-old patient with ENaC γ-subunit gene mutations via a retrospective chart review; reduction of daily dietary potassium intake from 40 to 20 mEq induced rapid restoration of volume depletion, as evidenced by weight gain, elevation of the serum sodium level from 133 to 141 mEq/L, decreased urinary sodium excretion, and normalized renin activity. The serum potassium level decreased from 5.6 to 4.5 mEq/L. Next, we attempted to elucidate the pathophysiological basis of the usefulness of potassium restriction, leveraged by the increased knowledge regarding the roles of with-no-lysine kinases (WNKs) in the distal nephron. When potassium is restricted, the WNK signal will turn "on" in the distal nephron via reduction in the intracellular chloride level. Consequently, the sodium reabsorption from the Na+Cl- cotransporter (NCC) in the distal convoluted tubule and possibly from pendrin in the β-intercalated cell will increase. Thus, potassium restriction causes NCC and pendrin to compensate for the non-functional ENaC in the collecting duct. In conclusion, dietary potassium restriction is one of the indispensable treatments for generalized PHA1.
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Affiliation(s)
- Masanori Adachi
- Department of Endocrinology and Metabolism, Kanagawa Children's Medical Center, Mutsukawa, 2-138-4, Minami-ku, Yokohama, 232-8555, Japan.
| | - Toshihiro Tajima
- Department of Pediatrics, Jichi Children's Hospital Medical Center Tochigi, Tochigi, Japan
| | - Koji Muroya
- Department of Endocrinology and Metabolism, Kanagawa Children's Medical Center, Mutsukawa, 2-138-4, Minami-ku, Yokohama, 232-8555, Japan
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14
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Yin LP, Zhu H, Zhu RY, Huang L. A novel SCNN1G mutation in a PHA I infant patient correlates with nephropathy. Biochem Biophys Res Commun 2019; 519:415-421. [PMID: 31522814 DOI: 10.1016/j.bbrc.2019.07.026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 07/06/2019] [Indexed: 10/26/2022]
Abstract
Systematic form of pseudohypoaldosteronism Type I (PHA I) is a rare recessive homozygous inherited syndrome characterized by severe salt loss, hyperkalemia, hyponatremia, metabolic acidosis, hyperaldosteronism and hyperreninemia. It is caused by mutations in one of the genes encoding the α, β and γ subunits of epithelial sodium channels (ENaC). In this study, we performed whole exome sequencing on an infant patient with PHA I as well as nephropathy. The result presented a novel homozygous six-base deletion in the γ subunit encoding gene SCNN1G. Then we correlated the mutant to kidney damage, along with transcriptional alterations of genes involved in inflammation, oxidative stress and apoptosis, via in vitro and in vivo tests. In addition, it was demonstrated that the SCNN1G defects triggered programmed cell death via inhibiting miR-21 and upregulating PTEN, which then orchestrated the key downstream regulators, including Bcl2, Bax2, and cleaved Caspse-3 in a way that favors cell apoptosis. The study enhances our understanding of the pathophysiology of the disorder of PHA I and the mechanisms of renal damage induced by the novel defect.
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Affiliation(s)
- Li-Ping Yin
- Pediatric Department, Zhongda Hospital of Southeast University, Nanjing, 210009, Jiangsu, China.
| | - Huan Zhu
- Pediatric Department, Zhongda Hospital of Southeast University, Nanjing, 210009, Jiangsu, China.
| | - Ru-Yuan Zhu
- Pediatric Department, Zhongda Hospital of Southeast University, Nanjing, 210009, Jiangsu, China.
| | - Li Huang
- Pediatric Department, Zhongda Hospital of Southeast University, Nanjing, 210009, Jiangsu, China.
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15
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Mezger A, Ruland A, Ruef P. Pseudohypoaldosteronismus Typ I. Monatsschr Kinderheilkd 2019. [DOI: 10.1007/s00112-019-00787-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Tanaka T, Oki E, Mori T, Tsuruga K, Sohara E, Uchida S, Tanaka H. Complete clinical resolution of a Japanese family with renal pseudohypoaldosteronism type 1 due to a novel NR3C2 mutation. Nephrology (Carlton) 2019; 24:489-490. [PMID: 30919533 DOI: 10.1111/nep.13391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/16/2018] [Indexed: 11/28/2022]
Affiliation(s)
- Tatsuhiko Tanaka
- Department of Pediatrics, Hirosaki University Hospital, Aomori, Japan
| | - Eishin Oki
- Department of Pediatrics, Tsugaru General Hospital, Aomori, Japan
| | - Takayasu Mori
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Kazushi Tsuruga
- Department of Pediatrics, Hirosaki University Hospital, Aomori, Japan
| | - Eisei Sohara
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Shinichi Uchida
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Hiroshi Tanaka
- Department of Pediatrics, Hirosaki University Hospital, Aomori, Japan.,Department of School Health Science, Hirosaki University Faculty of Education, Aomori, Japan
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