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Charoensri S, Auchus RJ. Therapeutic management of congenital forms of endocrine hypertension. Eur J Endocrinol 2023; 189:R11-R22. [PMID: 37847213 DOI: 10.1093/ejendo/lvad140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2023] [Revised: 08/15/2023] [Accepted: 09/19/2023] [Indexed: 10/18/2023]
Abstract
Congenital forms of endocrine hypertension are rare and potentially life-threatening disorders, primarily caused by genetic defects affecting adrenal steroid synthesis and activation pathways. These conditions exhibit diverse clinical manifestations, which can be distinguished by their unique molecular mechanisms and steroid profiles. Timely diagnosis and customized management approach are crucial to mitigate unfavorable outcomes associated with uncontrolled hypertension and other related conditions. Treatment options for these disorders depend on the distinct underlying pathophysiology, which involves specific pharmacological therapies or surgical adrenalectomy in some instances. This review article summarizes the current state of knowledge on the therapeutic management of congenital forms of endocrine hypertension, focusing on familial hyperaldosteronism (FH), congenital adrenal hyperplasia, apparent mineralocorticoid excess, and Liddle syndrome. We provide an overview of the genetic and molecular pathogenesis underlying each disorder, describe the clinical features, and discuss the various therapeutic approaches available and their risk of adverse effects, aiming to improve outcomes in patients with these rare and complex conditions.
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Affiliation(s)
- Suranut Charoensri
- Division of Endocrinology and Metabolism, Department of Medicine, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand
- Division of Metabolism, Endocrinology, and Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, United States
| | - Richard J Auchus
- Division of Metabolism, Endocrinology, and Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, United States
- Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109, United States
- Endocrinology & Metabolism Section, Medicine Service, LTC Charles S. Kettles VA Medical Center, Ann Arbor, MI 48104, United States
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2
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Metwalley KA, Farghaly HS. Overview of endocrine hypertension in children. PROGRESS IN PEDIATRIC CARDIOLOGY 2022. [DOI: 10.1016/j.ppedcard.2022.101581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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3
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Khandelwal P, Deinum J. Monogenic forms of low-renin hypertension: clinical and molecular insights. Pediatr Nephrol 2022; 37:1495-1509. [PMID: 34414500 DOI: 10.1007/s00467-021-05246-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 07/16/2021] [Accepted: 07/19/2021] [Indexed: 11/25/2022]
Abstract
Monogenic disorders of hypertension are a distinct group of diseases causing dysregulation of the renin-angiotensin-aldosterone system and are characterized by low plasma renin activity. These can chiefly be classified as causing (i) excessive aldosterone synthesis (familial hyperaldosteronism), (ii) dysregulated adrenal steroid metabolism and action (apparent mineralocorticoid excess, congenital adrenal hyperplasia, activating mineralocorticoid receptor mutation, primary glucocorticoid resistance), and (iii) hyperactivity of sodium and chloride transporters in the distal tubule (Liddle syndrome and pseudohypoaldosteronism type 2). The final common pathway is plasma volume expansion and catecholamine/sympathetic excess that causes urinary potassium wasting; hypokalemia and early-onset refractory hypertension are characteristic. However, several single gene defects may show phenotypic heterogeneity, presenting with mild hypertension with normal electrolytes. Evaluation is based on careful attention to family history, physical examination, and measurement of blood levels of potassium, renin, and aldosterone. Genetic sequencing is essential for precise diagnosis and individualized therapy. Early recognition and specific management improves prognosis and prevents long-term sequelae of severe hypertension.
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Affiliation(s)
- Priyanka Khandelwal
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, 110029, India.
| | - Jaap Deinum
- Department of Internal Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
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Alhasan K, D'Alessandri-Silva C, Mongia A, Topaloglu R, Tasic V, Filler G. Young Adults With Hereditary Tubular Diseases: Practical Aspects for Adult-Focused Colleagues. Adv Chronic Kidney Dis 2022; 29:292-307. [PMID: 36084976 DOI: 10.1053/j.ackd.2021.11.004] [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: 09/21/2021] [Revised: 11/07/2021] [Accepted: 11/15/2021] [Indexed: 11/11/2022]
Abstract
Recent advances in the management of kidney tubular diseases have resulted in a significant cohort of adolescents and young adults transitioning from pediatric- to adult-focused care. Most of the patients under adult-focused care have glomerular diseases, whereas rarer tubular diseases form a considerable proportion of pediatric patients. The purpose of this review is to highlight the clinical signs and symptoms of tubular disorders, as well as their diagnostic workup, including laboratory findings and imaging, during young adulthood. We will then discuss more common disorders such as cystinosis, cystinuria, distal kidney tubular acidosis, congenital nephrogenic diabetes insipidus, Dent disease, rickets, hypercalciuria, and syndromes such as Bartter, Fanconi, Gitelman, Liddle, and Lowe. This review is a practical guide on the diagnostic and therapeutic approach of tubular conditions affecting young adults who are transitioning to adult-focused care.
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Affiliation(s)
- Khalid Alhasan
- Department of Pediatrics, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Cynthia D'Alessandri-Silva
- Department of Pediatrics, University of Connecticut School of Medicine, Farmington, and Nephrology, Connecticut Children's Medical Center, Hartford, CT
| | - Anil Mongia
- Department of Pediatrics, SUNY Downstate Medical Center, Brooklyn, NY
| | - Rezan Topaloglu
- Department of Paediatrics, Division of Pediatric Nephrology, Hacettepe University School of Medicine, Ankara, Turkey
| | - Velibor Tasic
- University Children's Hospital, Medical School, Skopje, North Macedonia
| | - Guido Filler
- Department of Paediatrics, Division of Pediatric Nephrology, Western University, London, ON, Canada; Department of Medicine, Western University, London, ON, Canada; Department of Pathology and Laboratory Medicine, Western University, London, ON, Canada.
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Mareš Š, Filipovský J, Vlková K, Pešta M, Černá V, Hrabák J, Mlíková Seidlerová J, Mayer O. A novel nonsense mutation in the β-subunit of the epithelial sodium channel causing Liddle syndrome. Blood Press 2021; 30:291-299. [PMID: 34223773 DOI: 10.1080/08037051.2021.1942785] [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: 10/20/2022]
Abstract
PURPOSE Liddle syndrome is a hereditary form of arterial hypertension caused by mutations in the genes coding of the epithelial sodium channel - SCNN1A, SCNN1B and SCNN1G. It is characterised by early onset of hypertension and variable biochemical features such as hypokalaemia and low plasma concentrations of renin and aldosterone. Phenotypic variability is large and, therefore, LS is probably underdiagnosed. Our objective was to examine a family suspected from Liddle syndrome including genetic testing and evaluate clinical and biochemical features of affected family members. MATERIALS AND METHODS Thirteen probands from the Czech family, related by blood, underwent physical examination, laboratory tests, and genetic testing. Alleles of SCNN1B and SCNN1G genes were examined by PCR amplification and Sanger sequencing of amplicons. RESULTS We identified a novel mutation in the β-subunit of an epithelial sodium channel coded by the SCNN1B gene, causing the nonsense mutation in the protein sequence p.Tyr604*. This mutation was detected in 7 members of the family. The mutation carriers differed in the severity of hypertension and hypokalaemia which appeared only after diuretics in most of them; low aldosterone level (< 0.12 nmol/l) was, however, present in all. CONCLUSIONS This finding expands the spectrum of known mutations causing Liddle syndrome. Hypoaldosteronemia was 100% sensitive sign in the mutation carriers. Low levels are observed especially in the Caucasian population reaching 96% sensitivity. Assessment of plasma aldosterone concentration is helpful for differential diagnosis of arterial hypertension. CONDENSED ABSTRACT Liddle syndrome is a hereditary form of arterial hypertension caused by mutations in the genes encoding the epithelial sodium channel's α-, β- and γ-subunit. It is usually manifested by early onset of hypertension accompanied by low potassium and aldosterone levels. We performed a physical examination, laboratory tests and genetic screening in 13 members of a Czech family. We found a new mutation of the SCNN1B gene which encodes the β-subunit of the epithelial sodium channel. We describe the variability of each family member phenotype and point out the relevance of using aldosterone levels as a high sensitivity marker of Liddle syndrome in Caucasians.
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Affiliation(s)
- Štěpán Mareš
- Second Department of Internal Medicine, University Hospital, Pilsen, Czech Republic.,Biomedical Center, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic
| | - Jan Filipovský
- Second Department of Internal Medicine, University Hospital, Pilsen, Czech Republic.,Biomedical Center, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic
| | - Kateřina Vlková
- Biomedical Center, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic.,Department of Microbiology, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic
| | - Martin Pešta
- Biomedical Center, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic.,Institute of Biology, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic
| | - Václava Černá
- Institute of Biology, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic
| | - Jaroslav Hrabák
- Biomedical Center, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic.,Department of Microbiology, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic
| | - Jitka Mlíková Seidlerová
- Second Department of Internal Medicine, University Hospital, Pilsen, Czech Republic.,Biomedical Center, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic
| | - Otto Mayer
- Second Department of Internal Medicine, University Hospital, Pilsen, Czech Republic.,Biomedical Center, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic
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Brower RK, Ghlichloo IA, Shabgahi V, Elsholz D, Menon RK, Vyas AK. Liddle Syndrome due to a Novel c.1713 Deletion in the Epithelial Sodium Channel β-Subunit in a Normotensive Adolescent. AACE Clin Case Rep 2020; 7:65-68. [PMID: 33851023 PMCID: PMC7924163 DOI: 10.1016/j.aace.2020.11.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Objective Liddle syndrome (LS) is a rare autosomal dominant condition secondary to a gain-of-function mutation affecting the epithelial sodium channels (ENaCs) in the distal nephron. It presents with early-onset hypertension, hypokalemia, and metabolic alkalosis in the face of hyporeninemia and hypoaldosteronism. We report a novel mutation affecting the ENaCs in a normotensive adolescent with LS. Methods We describe a pediatric case of LS with a novel mutation and review the condition’s presentation and management. To date, 31 different mutations in the β- or γ-subunit of ENaCs have been reported as associated with LS. Results We describe a 16-year-old girl presenting with muscle cramps with a strong family history of hypertension and hypokalemia. Initial investigations revealed hypokalemia together with hypoaldosteronism and hyporeninemia. Subsequent genetic testing revealed a novel mutation in SCNN1B (deletion: c.1713delC), leading to the premature termination of the sodium channel epithelial 1 subunit-β protein and the LS phenotype. Treatment with triamterene (50 mg, twice daily) and potassium chloride (20 mEq, once daily) normalized the serum potassium and led to resolution of her muscle cramps. Conclusion It is essential to consider investigating the presence of rare genetic syndromes, like LS, when a patient presents with hypokalemia. Further studies are needed to understand the variable presentation of this condition.
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Affiliation(s)
- Raven K. Brower
- College of Medicine, California Northstate University, Elk Grove, California
| | - Ida A. Ghlichloo
- College of Medicine, California Northstate University, Elk Grove, California
| | - Venus Shabgahi
- College of Medicine, California Northstate University, Elk Grove, California
| | | | - Ram K. Menon
- Department of Pediatrics, University of Michigan, Ann Arbor, Michigan
| | - Arpita K. Vyas
- College of Medicine, California Northstate University, Elk Grove, California
- Address correspondence and reprint requests to Dr Arpita K Vyas, Elk Grove, CA 95757.
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Fan P, Zhang D, Pan XC, Yang KQ, Zhang QY, Lu YT, Zhang Y, Liu XY, Ma WJ, Zhang HM, Song L, Cai J, Liu YX, Zhou XL. Premature Stroke Secondary to Severe Hypertension Results from Liddle Syndrome Caused by a Novel SCNN1B Mutation. Kidney Blood Press Res 2020; 45:603-611. [PMID: 32698182 DOI: 10.1159/000507580] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 03/28/2020] [Indexed: 11/19/2022] Open
Abstract
INTRODUCTION Liddle syndrome (LS), an autosomal dominant and inherited monogenic hypertension syndrome caused by pathogenic mutations in the epithelial sodium channel (ENaC) genes SCNN1A, SCNN1B, and SCNN1G. OBJECTIVE This study was designed to identify a novel SCNN1B missense mutation in a Chinese family with a history of stroke, and to confirm that the identified mutation is responsible for LS in this family. METHODS DNA samples were collected from the proband and 11 additional relatives. Next-generation sequencing was performed in the proband to find candidate variants. In order to exclude genetic polymorphism, the candidate variantin SCNN1B was verified in other family members, 100 hypertensives, and 100 healthy controls by Sanger sequencing. RESULTS Genetic testing revealeda novel and rare heterozygous variant in SCNN1B in the proband. This variant resulted in a substitution of threonine instead of proline at codon 617, altering the PY motif of β-ENaC. The identified mutation was only verified in 5 relatives. In silico analyses indicated that this variant was highly pathogenic. In this family, phenotypic heterogeneity was present among 6 LS patients. Tailored medicine with amiloride was effective in controlling hypertension and improving the serum potassium concentration in patients with LS. CONCLUSIONS We identified a novel SCNN1B mutation (c.1849C>A) in a family affected by LS. Patients with LS, especially those with severe hypertension, should be alert for the occurrence of premature stroke. Timely diagnosis using genetic testing and tailored treatment with amiloride can help LS patients to avoid severe complications.
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Affiliation(s)
- Peng Fan
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Di Zhang
- Emergency and Critical Care Center, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xiao-Cheng Pan
- Graduate School, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Kun-Qi Yang
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Qiong-Yu Zhang
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Yi-Ting Lu
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Ying Zhang
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xue-Ying Liu
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Wen-Jun Ma
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Hui-Min Zhang
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Lei Song
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Jun Cai
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Ya-Xin Liu
- Emergency and Critical Care Center, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China,
| | - Xian-Liang Zhou
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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Macumber I, Flynn JT. Does treatment-resistant hypertension exist in children? A review of the evidence. Pediatr Nephrol 2020; 35:969-976. [PMID: 31147776 DOI: 10.1007/s00467-019-04268-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 03/20/2019] [Accepted: 04/18/2019] [Indexed: 12/23/2022]
Abstract
Treatment-resistant hypertension (TRH) is a well-described condition in adult patients that is associated with poor clinical outcomes. While case reports of hypertension resistant to therapy in children have been published, it is unclear if TRH truly exists in childhood. This educational review will briefly summarize recent evidence and recommendations for TRH in adults, as well as will review the literature regarding medically resistant hypertension in children and adolescents. Finally, we propose a clinical approach for evaluation hypertensive children and adolescents with apparent treatment resistance.
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Affiliation(s)
- Ian Macumber
- Connecticut Children's Medical Center, 282 Washington St, Hartford, CT, 06106, USA.
| | - Joseph T Flynn
- Seattle Children's Hospital, 4800 Sand Point Way NE, Seattle, WA, 98105, USA
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Lu YT, Fan P, Zhang D, Zhang Y, Meng X, Zhang QY, Zhao L, Yang KQ, Zhou XL. Overview of Monogenic Forms of Hypertension Combined With Hypokalemia. Front Pediatr 2020; 8:543309. [PMID: 33569358 PMCID: PMC7868374 DOI: 10.3389/fped.2020.543309] [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: 03/16/2020] [Accepted: 12/29/2020] [Indexed: 12/26/2022] Open
Abstract
Hypertension is an important risk factor in many conditions and creates a heavy burden of disease and mortality globally. Polygenic hypertension is the most common form; however, it is increasingly recognized that monogenic hypertension is not rare, especially in patients with electrolyte disorders. Single genetic alterations are associated with plasma volume expansion and catecholamines/sympathetic excess with simultaneously increased potassium excretion in the urine and potassium intracellular shift. Early-onset refractory hypertension and profound hypokalemia are characteristics of monogenic hypertension. However, accumulated evidence shows the existence of phenotypic heterogeneity in monogenic hypertension meaning that, even for mild symptoms, clinicians cannot easily exclude the possibility of monogenic hypertension. Genetic, epigenetic and non-genetic factors are all possible mechanisms influencing phenotypic diversity. Genetic sequencing is a precise and efficient method that can broaden the mutant gene spectrum of the disease and is very helpful for understanding the pathophysiology of monogenic hypertension. Genetic sequencing, along with biochemical tests and imaging modalities, is essential for the early diagnosis and targeted management of monogenic hypertension to avoid long-term catastrophic complications.
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Affiliation(s)
- Yi-Ting Lu
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Peng Fan
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Di Zhang
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Ying Zhang
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xu Meng
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Qiong-Yu Zhang
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Lin Zhao
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Kun-Qi Yang
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xian-Liang Zhou
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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Enslow BT, Stockand JD, Berman JM. Liddle's syndrome mechanisms, diagnosis and management. Integr Blood Press Control 2019; 12:13-22. [PMID: 31564964 PMCID: PMC6731958 DOI: 10.2147/ibpc.s188869] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2019] [Accepted: 08/23/2019] [Indexed: 12/26/2022] Open
Abstract
Liddle's syndrome is a genetic disorder characterized by hypertension with hypokalemic metabolic alkalosis, hyporeninemia and suppressed aldosterone secretion that often appears early in life. It results from inappropriately elevated sodium reabsorption in the distal nephron. Liddle's syndrome is caused by mutations to subunits of the Epithelial Sodium Channel (ENaC). Among other mechanisms, such mutations typically prevent ubiquitination of these subunits, slowing the rate at which they are internalized from the membrane, resulting in an elevation of channel activity. A minority of Liddle's syndrome mutations, though, result in a complementary effect that also elevates activity by increasing the probability that ENaC channels within the membrane are open. Potassium-sparing diuretics such as amiloride and triamterene reduce ENaC activity, and in combination with a reduced sodium diet can restore normotension and electrolyte imbalance in Liddle's syndrome patients and animal models. Liddle's syndrome can be diagnosed clinically by phenotype and confirmed through genetic testing. This review examines the clinical features of Liddle's syndrome, the differential diagnosis of Liddle's syndrome and differentiation from other genetic diseases with similar phenotype, and what is currently known about the population-level prevalence of Liddle's syndrome. This review gives special focus to the molecular mechanisms of Liddle's syndrome.
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Affiliation(s)
| | | | - Jonathan M Berman
- New York Institute of Technology College of Osteopathic Medicine at Arkansas State University, Jonesboro, AR, USA
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Fan P, Lu CX, Yang KQ, Lu PP, Hao SF, Luo F, Zhang HM, Song L, Wu HY, Cai J, Zhang X, Zhou XL. Truncated Epithelial Sodium Channel β Subunit Responsible for Liddle Syndrome in a Chinese Family. Kidney Blood Press Res 2019; 44:942-949. [DOI: 10.1159/000500919] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Accepted: 05/12/2019] [Indexed: 11/19/2022] Open
Abstract
Background/Aims: Liddle syndrome (LS) is a rare autosomal dominant disease caused by mutations in genes coding for epithelial sodium channel (ENaC) subunits. The aim of this study was to identify the mutation responsible for the LS in an extended Chinese family. Methods: DNA samples from the proband with early-onset, treatment-resistant hypertension, and hypokalemia and 19 additional relatives were all sequenced for mutations in exon 13 of the β-ENaC and γ-ENaC genes, using amplification by polymerase chain reaction and direct DNA sequencing. Results: Genetic testing of exon 13 of SCNN1B revealed duplication of guanine into a string of 3 guanines located at codon 602. This frameshift mutation is predicted to generate a premature stop codon at position 607, resulting in truncated β-ENaC lacking the remaining 34 amino acids, including the crucial PY motif. Among a total of 9 participants with the identical mutation, different phenotypes were identified. Tailored treatment with amiloride was safe and effective in alleviating disease symptoms in LS. No mutation of SCNN1G was identified in any of the examined participants. Conclusions: We report here a family affected by LS harboring a frameshift mutation (c.1806dupG) with a premature stop codon deleting the PY motif of β-ENaC. Our study demonstrates that the earlier LS patients are diagnosed by genetic testing and treated with tailored medication, the greater the likelihood of preventing or minimizing complications in the vasculature and target organs.
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12
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Fan P, Zhao YM, Zhang D, Liao Y, Yang KQ, Tian T, Lou Y, Luo F, Ma WJ, Zhang HM, Song L, Cai J, Liu YX, Zhou XL. A Novel Frameshift Mutation of SCNN1G Causing Liddle Syndrome with Normokalemia. Am J Hypertens 2019; 32:752-758. [PMID: 30977777 PMCID: PMC6636789 DOI: 10.1093/ajh/hpz053] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 03/13/2019] [Accepted: 04/09/2019] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Liddle syndrome (LS) is an autosomal dominant disorder caused by single-gene mutations of the epithelial sodium channel (ENaC). It is characterized by early-onset hypertension, spontaneous hypokalemia and low plasma renin and aldosterone concentrations. In this study, we reported an LS pedigree with normokalemia resulting from a novel SCNN1G frameshift mutation. METHODS Peripheral blood samples were collected from the proband and eight family members for DNA extraction. Next-generation sequencing and Sanger sequencing were performed to identify the SCNN1G mutation. Clinical examinations were used to comprehensively evaluate the phenotypes of two patients. RESULTS Genetic analysis identified a novel SCNN1G frameshift mutation, p.Arg586Valfs*598, in the proband with LS. This heterozygous frameshift mutation generated a premature stop codon and deleted the vital PY motif of ENaC. The same mutation was present in his elder brother with LS, and his mother without any LS symptoms. Biochemical examination showed normokalemia in the three mutation carriers. The mutation identified was not found in any other family members, 100 hypertensives, or 100 healthy controls. CONCLUSIONS Our study identified a novel SCNN1G frameshift mutation in a Chinese family with LS, expanding the genetic spectrum of SCNN1G. Genetic testing helped us identify LS with a pathogenic mutation when the genotypes and phenotype were not completely consistent because of the hypokalemia. This case emphasizes that once a proband is diagnosed with LS by genetic testing, family genetic sequencing is necessary for early diagnosis and intervention for other family members, to protect against severe cardiovascular complications.
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Affiliation(s)
- Peng Fan
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Yu-Mo Zhao
- Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Di Zhang
- Department of Emergency and Critical Care Center, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Ying Liao
- Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Kun-Qi Yang
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Tao Tian
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Ying Lou
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Fang Luo
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Wen-Jun Ma
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Hui-Min Zhang
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Lei Song
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Jun Cai
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Ya-Xin Liu
- Department of Emergency and Critical Care Center, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xian-Liang Zhou
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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Fan P, Lu CX, Zhang D, Yang KQ, Lu PP, Zhang Y, Meng X, Hao SF, Luo F, Liu YX, Zhang HM, Song L, Cai J, Zhang X, Zhou XL. Liddle syndrome misdiagnosed as primary aldosteronism resulting from a novel frameshift mutation of SCNN1B. Endocr Connect 2018; 7:1528-1534. [PMID: 30496127 PMCID: PMC6311463 DOI: 10.1530/ec-18-0484] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Accepted: 11/28/2018] [Indexed: 12/18/2022]
Abstract
Liddle syndrome (LS), a monogenetic autosomal dominant disorder, is mainly characterized by early-onset hypertension and hypokalemia. Clinically, misdiagnosis or missing diagnosis is common, since clinical phenotypes of LS are variable and nonspecific. We report a family with misdiagnosis of primary aldosteronism (PA), but identify as LS with a pathogenic frameshift mutation of the epithelial sodium channel (ENaC) β subunit. DNA samples were collected from a 32-year-old proband and 31 other relatives in the same family. A designed panel including 41 genes associated with monogenic hypertension was screened using next-generation sequencing. The best candidate disease-causing variants were verified by Sanger sequencing. Genetic analysis of the proband revealed a novel frameshift mutation c.1838delC (p.Pro613Glnfs*675) in exon 13 of SCNN1B. This heterozygous mutation involved the deletion of a cytosine from a string of three consecutive cytosines located at codons 612 to 613 and resulted in deletion of the crucial PY motif and elongation of the β-ENaC protein. The identical mutation was also found in 12 affected family members. Amiloride was effective in alleviating LS for patients. There were no SCNN1A or SCNN1G mutations in this family. Our study emphasizes the importance of considering LS in the differential diagnosis of early-onset hypertension. The identification of a novel frameshift mutation of SCNN1B enriches the genetic spectrum of LS and has allowed treatment of this affected family to prevent severe complications.
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Affiliation(s)
- Peng Fan
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Chao-Xia Lu
- McKusick-Zhang Center for Genetic Medicine, State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Di Zhang
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Kun-Qi Yang
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Pei-Pei Lu
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Ying Zhang
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xu Meng
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Su-Fang Hao
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Fang Luo
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Ya-Xin Liu
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Hui-Min Zhang
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Lei Song
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Jun Cai
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xue Zhang
- McKusick-Zhang Center for Genetic Medicine, State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Correspondence should be addressed to X Zhang or X-L Zhou: or
| | - Xian-Liang Zhou
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Correspondence should be addressed to X Zhang or X-L Zhou: or
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Abstract
Liddle syndrome is an inherited form of low-renin hypertension, transmitted with an autosomal dominant pattern. The molecular basis of Liddle syndrome resides in germline mutations of the SCNN1A, SCNN1B and SCNN1G genes, encoding the α, β, and γ-subunits of the epithelial Na+ channel (ENaC), respectively. To date, 31 different causative mutations have been reported in 72 families from four continents. The majority of the substitutions cause an increased expression of the channel at the distal nephron apical membrane, with subsequent enhanced renal sodium reabsorption. The most common clinical presentation of the disease is early onset hypertension, hypokalemia, metabolic alkalosis, suppressed plasma renin activity and low plasma aldosterone. Consequently, treatment of Liddle syndrome is based on the administration of ENaC blockers, amiloride and triamterene. Herein, we discuss the genetic basis, clinical presentation, diagnosis and treatment of Liddle syndrome. Finally, we report a new case in an Italian family, caused by a SCNN1B p.Pro618Leu substitution.
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The phosphorylation site T613 in the β-subunit of rat epithelial Na+ channel (ENaC) modulates channel inhibition by Nedd4-2. Pflugers Arch 2018; 470:649-660. [DOI: 10.1007/s00424-018-2115-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 01/17/2018] [Accepted: 01/23/2018] [Indexed: 10/18/2022]
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Polfus LM, Boerwinkle E, Gibbs RA, Metcalf G, Muzny D, Veeraraghavan N, Grove M, Shete S, Wallace S, Milewicz D, Hanchard N, Lupski JR, Hashmi SS, Gupta-Malhotra M. Whole-exome sequencing reveals an inherited R566X mutation of the epithelial sodium channel β-subunit in a case of early-onset phenotype of Liddle syndrome. Cold Spring Harb Mol Case Stud 2017; 2:a001255. [PMID: 27900368 PMCID: PMC5111009 DOI: 10.1101/mcs.a001255] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
To comprehensively evaluate a European–American child with severe hypertension, whole-exome sequencing (WES) was performed on the child and parents, which identified causal variation of the proband's early-onset disease. The proband's hypertension was resistant to treatment, requiring a multiple drug regimen including amiloride, spironolactone, and hydrochlorothiazide. We suspected a monogenic form of hypertension because of the persistent hypokalemia with low plasma levels of renin and aldosterone. To address this, we focused on rare functional variants and indels, and performed gene-based tests incorporating linkage scores and allele frequency and filtered on deleterious functional mutations. Drawing upon clinical presentation, 27 genes were selected evidenced to cause monogenic hypertension and matched to the gene-based results. This resulted in the identification of a stop-gain mutation in an epithelial sodium channel (ENaC), SCNN1B, an established Liddle syndrome gene, shared by the child and her father. Interestingly, the father also harbored a missense mutation (p.Trp552Arg) in the α-subunit of the ENaC trimer, SCNN1A, possibly pointing to pseudohypoaldosteronism type I. This case is unique in that we present the early-onset disease and treatment response caused by a canonical stop-gain mutation (p.Arg566*) as well as ENaC digenic hits in the father, emphasizing the utility of WES informing precision medicine.
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Affiliation(s)
- Linda M Polfus
- Human Genetics Center, The University of Texas Health Science Center at Houston, Houston, Texas 70130, USA
| | - Eric Boerwinkle
- Human Genetics Center, The University of Texas Health Science Center at Houston, Houston, Texas 70130, USA;; Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas 70130, USA
| | - Richard A Gibbs
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas 70130, USA
| | - Ginger Metcalf
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas 70130, USA
| | - Donna Muzny
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas 70130, USA
| | | | - Megan Grove
- Human Genetics Center, The University of Texas Health Science Center at Houston, Houston, Texas 70130, USA
| | - Sanjay Shete
- Department of Biostatistics, MD Anderson Cancer Center, The University of Texas Health Science Center, Houston, Texas 77030, USA
| | - Stephanie Wallace
- Division of Medical Genetics, Department of Internal Medicine, The University of Texas Health Science Center, Houston, Texas 77030, USA
| | - Dianna Milewicz
- Division of Medical Genetics, Department of Internal Medicine, The University of Texas Health Science Center, Houston, Texas 77030, USA
| | - Neil Hanchard
- Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 70130, USA
| | - James R Lupski
- Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 70130, USA
| | - Syed Shahrukh Hashmi
- Department of Pediatrics, Children's Memorial Hermann Hospital, The University of Texas Health Science Center, Houston, Texas, Medical School, Texas 77030, USA
| | - Monesha Gupta-Malhotra
- Department of Pediatric Cardiology, Johns Hopkins All Children's Hospital, St. Petersburg, Florida 33701, USA
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Yang KQ, Lu CX, Fan P, Zhang Y, Meng X, Dong XQ, Luo F, Liu YX, Zhang HM, Wu HY, Cai J, Zhang X, Zhou XL. Genetic screening of SCNN1B and SCNN1G genes in early-onset hypertensive patients helps to identify Liddle syndrome. Clin Exp Hypertens 2017; 40:107-111. [PMID: 28718682 DOI: 10.1080/10641963.2017.1334799] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Kun-Qi Yang
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Chao-Xia Lu
- McKusick-Zhang Center for Genetic Medicine, State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Peng Fan
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Ying Zhang
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xu Meng
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xue-Qi Dong
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Fang Luo
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Ya-Xin Liu
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Hui-Min Zhang
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Hai-Ying Wu
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Jun Cai
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xue Zhang
- McKusick-Zhang Center for Genetic Medicine, State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xian-Liang Zhou
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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Pichurin PN, Schwartz GL. Genetic testing helps to confirm the diagnosis and initiate appropriate treatment, a case of Liddle syndrome. JOURNAL OF THE AMERICAN SOCIETY OF HYPERTENSION : JASH 2017; 11:134-135. [PMID: 28229899 DOI: 10.1016/j.jash.2017.01.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 01/12/2017] [Indexed: 06/06/2023]
Affiliation(s)
- Pavel N Pichurin
- Department of Clinical Genomics, Mayo Clinic, Rochester, MN, USA
| | - Garry L Schwartz
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA.
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Büyükkaragöz B, Yilmaz AC, Karcaaltincaba D, Ozdemir O, Ludwig M. Liddle syndrome in a Turkish family with heterogeneous phenotypes. Pediatr Int 2016; 58:801-4. [PMID: 27325428 DOI: 10.1111/ped.12985] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 02/13/2016] [Accepted: 03/09/2016] [Indexed: 11/30/2022]
Abstract
Liddle syndrome (LS) is a familial disease characterized by early onset hypertension (HT). Although regarded as rare, its incidence may be greater than expected because the classical findings of hypokalemic metabolic alkalosis with suppressed renin and aldosterone levels are not consistently present. Herein, we present the case of an adolescent boy and maternal relatives who were followed up with misdiagnosis of essential HT for a long duration. Clinical diagnosis of LS was confirmed on genetic analysis. Despite carrying the same mutation, the index patient and the family members manifested heterogeneous phenotypes of the disease including age at presentation, degree of HT, presence of hypokalemia and renal/cardiac complications. LS should be considered in the differential diagnosis of HT in children with a strong family history of HT resistant to conventional treatment; and genetic screening should be performed in these circumstances.
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Affiliation(s)
- Bahar Büyükkaragöz
- Department of Pediatric Nephrology, Keciören Research and Training Hospital, Ankara, Turkey
| | - Aysun Caltik Yilmaz
- Department of Pediatric Nephrology, Keciören Research and Training Hospital, Ankara, Turkey
| | | | - Osman Ozdemir
- Department of Pediatric Cardiology, Keciören Research and Training Hospital, Ankara, Turkey
| | - Michael Ludwig
- Department of Clinical Biochemistry and Clinical Pharmacology, University of Bonn, Bonn, Germany
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Hanukoglu I, Hanukoglu A. Epithelial sodium channel (ENaC) family: Phylogeny, structure-function, tissue distribution, and associated inherited diseases. Gene 2016; 579:95-132. [PMID: 26772908 PMCID: PMC4756657 DOI: 10.1016/j.gene.2015.12.061] [Citation(s) in RCA: 250] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Revised: 12/20/2015] [Accepted: 12/22/2015] [Indexed: 01/24/2023]
Abstract
The epithelial sodium channel (ENaC) is composed of three homologous subunits and allows the flow of Na(+) ions across high resistance epithelia, maintaining body salt and water homeostasis. ENaC dependent reabsorption of Na(+) in the kidney tubules regulates extracellular fluid (ECF) volume and blood pressure by modulating osmolarity. In multi-ciliated cells, ENaC is located in cilia and plays an essential role in the regulation of epithelial surface liquid volume necessary for cilial transport of mucus and gametes in the respiratory and reproductive tracts respectively. The subunits that form ENaC (named as alpha, beta, gamma and delta, encoded by genes SCNN1A, SCNN1B, SCNN1G, and SCNN1D) are members of the ENaC/Degenerin superfamily. The earliest appearance of ENaC orthologs is in the genomes of the most ancient vertebrate taxon, Cyclostomata (jawless vertebrates) including lampreys, followed by earliest representatives of Gnathostomata (jawed vertebrates) including cartilaginous sharks. Among Euteleostomi (bony vertebrates), Actinopterygii (ray finned-fishes) branch has lost ENaC genes. Yet, most animals in the Sarcopterygii (lobe-finned fish) branch including Tetrapoda, amphibians and amniotes (lizards, crocodiles, birds, and mammals), have four ENaC paralogs. We compared the sequences of ENaC orthologs from 20 species and established criteria for the identification of ENaC orthologs and paralogs, and their distinction from other members of the ENaC/Degenerin superfamily, especially ASIC family. Differences between ENaCs and ASICs are summarized in view of their physiological functions and tissue distributions. Structural motifs that are conserved throughout vertebrate ENaCs are highlighted. We also present a comparative overview of the genotype-phenotype relationships in inherited diseases associated with ENaC mutations, including multisystem pseudohypoaldosteronism (PHA1B), Liddle syndrome, cystic fibrosis-like disease and essential hypertension.
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Affiliation(s)
- Israel Hanukoglu
- Laboratory of Cell Biology, Faculty of Natural Sciences, Ariel University, Ariel, Israel.
| | - Aaron Hanukoglu
- Division of Pediatric Endocrinology, E. Wolfson Medical Center, Holon, Israel; Sackler School of Medicine, Tel-Aviv University, Tel Aviv, Israel
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Khosravi M, Walsh SB. The long-term complications of the inherited tubulopathies: an adult perspective. Pediatr Nephrol 2015; 30:385-95. [PMID: 24566812 DOI: 10.1007/s00467-014-2779-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Revised: 01/23/2014] [Accepted: 01/27/2014] [Indexed: 11/25/2022]
Abstract
The inherited tubulopathies are lifelong disorders and their clinical features and complications may present quite different challenges in adulthood from those in childhood. In this review we outline the pathophysiology and documented complications (including the late and unusual) of the monogenic tubulopathies from the perspective of the adult nephrologist.
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Affiliation(s)
- Maryam Khosravi
- UCL Centre for Nephrology, Royal Free Hospital, University College London, London, UK
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Epidemiology of Secondary Hypertension in Children. CURRENT CARDIOVASCULAR RISK REPORTS 2014. [DOI: 10.1007/s12170-014-0388-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Gao L, Wang L, Liu Y, Zhou X, Hui R, Hu A. A family with Liddle syndrome caused by a novel missense mutation in the PY motif of the beta-subunit of the epithelial sodium channel. J Pediatr 2013; 162:166-70. [PMID: 22809657 DOI: 10.1016/j.jpeds.2012.06.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Revised: 05/23/2012] [Accepted: 06/07/2012] [Indexed: 11/17/2022]
Abstract
OBJECTIVE To identify the gene mutation in β and γ subunits of the epithelial sodium channel (ENaC) in an adolescent and family members with Liddle syndrome, an autosomal dominant form of secondary hypertension. STUDY DESIGN We screened an adolescent with severe hypertension who was clinically diagnosed with Liddle syndrome for mutations in the C-terminus of the SCNN1B and SCNN1G genes. We also screened for these mutations in his family members, in 100 hypertensive patients, and in 100 controls. RESULTS The index case, a 14-year-old boy, was diagnosed with Liddle syndrome by the identification of a novel missense mutation, P614L, in the PY motif of the β subunit of the ENaC. Testing of relatives considered at risk revealed 6 subjects heterozygous for the mutation. All genetically affected subjects had a history of severe hypertension as well as hypokalemia. No other variants in the β or γ subunits of the ENaC were detected. CONCLUSION Based on direct DNA sequencing, we have detected a novel mutation that causes Liddle syndrome. This confirms the diagnosis and helps guide effective therapy for this adolescent and his affected relatives. These findings provide further evidence that the conserved PY motif is critical to regulation of ENaC activity.
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Affiliation(s)
- Linggen Gao
- Department of Cardiology, FuWai Hospital and Cardiovascular Institute, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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