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Holm-Yildiz S, Krag T, Dysgaard T, Pedersen BS, Medeiros E, Vissing J. Quality of life in hypokalemic periodic paralysis - a survey. Neuromuscul Disord 2024; 41:24-28. [PMID: 38870649 DOI: 10.1016/j.nmd.2024.05.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 04/03/2024] [Accepted: 05/29/2024] [Indexed: 06/15/2024]
Abstract
Primary hypokalemic periodic paralysis (HypoPP) is a skeletal muscle channelopathy most commonly caused by pathogenic variants in the calcium channel gene, CACNA1S. HypoPP can present with attacks of paralysis and/or permanent muscle weakness. Previous studies have shown that patients with HypoPP can have impaired quality of life (QoL). In this cross-sectional study, we aimed to describe the QoL in patients with HypoPP caused by pathogenic variants in CACNA1S using The Individualized Neuromuscular Quality of Life (INQoL) questionnaire, a validated tool to measure the QoL of patients with neuromuscular diseases (higher score, worse QoL). We showed that muscle weakness and fatigue were the symptoms with the greatest impact on participants' lives and that "activities", in the life domain of the INQoL, was most affected by HypoPP. Furthermore, we showed that the total INQoL score increased with age. Low QoL was primarily driven by progressive permanent muscle weakness and not attacks of paralysis, although half of the participants reported that attacks of paralysis challenged their daily life. The results suggest that special attention should be given to muscle weakness and fatigue in patients with HypoPP.
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Affiliation(s)
- Sonja Holm-Yildiz
- Copenhagen Neuromuscular Center, Department of Neurology, Rigshospitalet, University of Copenhagen 8077, Inge Lehmanns Vej 8, DK-2100 Copenhagen, Denmark.
| | - Thomas Krag
- Copenhagen Neuromuscular Center, Department of Neurology, Rigshospitalet, University of Copenhagen 8077, Inge Lehmanns Vej 8, DK-2100 Copenhagen, Denmark
| | - Tina Dysgaard
- Copenhagen Neuromuscular Center, Department of Neurology, Rigshospitalet, University of Copenhagen 8077, Inge Lehmanns Vej 8, DK-2100 Copenhagen, Denmark
| | - Brit Stævnsbo Pedersen
- Copenhagen Neuromuscular Center, Department of Neurology, Rigshospitalet, University of Copenhagen 8077, Inge Lehmanns Vej 8, DK-2100 Copenhagen, Denmark
| | - Estephani Medeiros
- Copenhagen Neuromuscular Center, Department of Neurology, Rigshospitalet, University of Copenhagen 8077, Inge Lehmanns Vej 8, DK-2100 Copenhagen, Denmark
| | - John Vissing
- Copenhagen Neuromuscular Center, Department of Neurology, Rigshospitalet, University of Copenhagen 8077, Inge Lehmanns Vej 8, DK-2100 Copenhagen, Denmark
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2
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Vassiliadis RM. Anaesthetic management of a parturient with hypokalaemic periodic paralysis for caesarean section: A case report and review of the literature. Anaesth Intensive Care 2024; 52:250-255. [PMID: 38879798 DOI: 10.1177/0310057x231178840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/31/2024]
Abstract
A 32-year-old multigravida woman, with known familial hypokalaemic periodic paralysis, underwent spinal anaesthesia for an elective lower segment caesarean section. There are several case reports in the literature discussing the optimal anaesthetic technique. In the past there has not been an emphasis on aggressive and early potassium replacement. A target level to commence replacement of potassium at 4.0 mmol/L or less is proposed. Careful preoperative preparation, frequent perioperative monitoring and early potassium replacement resulted in no perioperative episodes of weakness in this case, in contrast with other case reports where potassium was either not monitored or not replaced early enough, resulting in postoperative attacks. Another factor to consider in hypokalaemic periodic paralysis is the avoidance of triggers, including certain medications. Misoprostol was used in this instance to avoid potential electrolyte derangements from other uterotonics.
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3
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Jha N, Balachandran DM, Thabah MM, Jha AK. Diagnosis, management and outcomes of primary hypokalemic periodic paralysis during pregnancy. Obstet Med 2024; 17:119-123. [PMID: 38784184 PMCID: PMC11110751 DOI: 10.1177/1753495x221144670] [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: 04/13/2022] [Revised: 11/22/2022] [Accepted: 11/24/2022] [Indexed: 09/11/2023] Open
Abstract
Primary hypokalaemic periodic paralysis during pregnancy has been rarely reported. Four pregnant women with the acute onset of flaccid paralysis presented between January 2018 and December 2021. Focussed history and physical examination helped an appropriate radiological and laboratory investigation plan to be made. All women recovered within 4-7 days of potassium supplementation. Supplemental potassium continued until delivery. A pain management plan with continuous epidural infusion helped in avoiding stress-induced hypokalaemia. None of the women developed an episode of muscle weakness during the intervening period. In conclusion, a focussed history and targeted laboratory investigation are needed to diagnose primary hypokalaemic periodic paralysis. Early administration of oral or intravenous potassium is crucial in improving fetomaternal outcomes.
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Affiliation(s)
- Nivedita Jha
- Department of Obstetrics and Gynaecology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India
| | - Divya Mecheril Balachandran
- Department of Obstetrics and Gynaecology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India
| | - Molly Mary Thabah
- Department of Medicine, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India
| | - Ajay Kumar Jha
- Department of Anaesthesiology and Critical Care, Jawaharlal Institute of Medical Education and Research, Pondicherry, India
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4
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Zou X, Zhang Z, Lu H, Zhao W, Pan L, Chen Y. Functional effects of drugs and toxins interacting with Na V1.4. Front Pharmacol 2024; 15:1378315. [PMID: 38725668 PMCID: PMC11079311 DOI: 10.3389/fphar.2024.1378315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Accepted: 04/08/2024] [Indexed: 05/12/2024] Open
Abstract
NaV1.4 is a voltage-gated sodium channel subtype that is predominantly expressed in skeletal muscle cells. It is essential for producing action potentials and stimulating muscle contraction, and mutations in NaV1.4 can cause various muscle disorders. The discovery of the cryo-EM structure of NaV1.4 in complex with β1 has opened new possibilities for designing drugs and toxins that target NaV1.4. In this review, we summarize the current understanding of channelopathies, the binding sites and functions of chemicals including medicine and toxins that interact with NaV1.4. These substances could be considered novel candidate compounds or tools to develop more potent and selective drugs targeting NaV1.4. Therefore, studying NaV1.4 pharmacology is both theoretically and practically meaningful.
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Affiliation(s)
- Xinyi Zou
- Zhejiang Provincial Key Laboratory of Resources Protection and Innovation of Traditional Chinese Medicine, College of Food and Health, Zhejiang Agriculture and Forestry University, Hangzhou, China
| | - Zixuan Zhang
- Zhejiang Provincial Key Laboratory of Resources Protection and Innovation of Traditional Chinese Medicine, College of Food and Health, Zhejiang Agriculture and Forestry University, Hangzhou, China
| | - Hui Lu
- Zhejiang Provincial Key Laboratory of Resources Protection and Innovation of Traditional Chinese Medicine, College of Food and Health, Zhejiang Agriculture and Forestry University, Hangzhou, China
| | - Wei Zhao
- Zhejiang Provincial Key Laboratory of Resources Protection and Innovation of Traditional Chinese Medicine, College of Food and Health, Zhejiang Agriculture and Forestry University, Hangzhou, China
| | - Lanying Pan
- Key Laboratory of Artificial Organs and Computational Medicine in Zhejiang Province, Shulan International Medical College, Zhejiang Shuren University, Hangzhou, China
| | - Yuan Chen
- Zhejiang Provincial Key Laboratory of Resources Protection and Innovation of Traditional Chinese Medicine, College of Food and Health, Zhejiang Agriculture and Forestry University, Hangzhou, China
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5
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Eltokhi A, Lundstrom BN, Li J, Zweifel LS, Catterall WA, Gamal El-Din TM. Pathogenic gating pore current conducted by autism-related mutations in the Na V1.2 brain sodium channel. Proc Natl Acad Sci U S A 2024; 121:e2317769121. [PMID: 38564633 PMCID: PMC11009634 DOI: 10.1073/pnas.2317769121] [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: 10/23/2023] [Accepted: 02/26/2024] [Indexed: 04/04/2024] Open
Abstract
Autism spectrum disorder (ASD) is a complex neurodevelopmental condition characterized by social and communication deficits and repetitive behaviors. The genetic heterogeneity of ASD presents a challenge to the development of an effective treatment targeting the underlying molecular defects. ASD gating charge mutations in the KCNQ/KV7 potassium channel cause gating pore currents (Igp) and impair action potential (AP) firing of dopaminergic neurons in brain slices. Here, we investigated ASD gating charge mutations of the voltage-gated SCN2A/NaV1.2 brain sodium channel, which ranked high among the ion channel genes with mutations in individuals with ASD. Our results show that ASD mutations in the gating charges R2 in Domain-II (R853Q), and R1 (R1626Q) and R2 (R1629H) in Domain-IV of NaV1.2 caused Igp in the resting state of ~0.1% of the amplitude of central pore current. The R1626Q mutant also caused significant changes in the voltage dependence of fast inactivation, and the R1629H mutant conducted proton-selective Igp. These potentially pathogenic Igp were exacerbated by the absence of the extracellular Mg2+ and Ca2+. In silico simulation of the effects of these mutations in a conductance-based single-compartment cortical neuron model suggests that the inward Igp reduces the time to peak for the first AP in a train, increases AP rates during a train of stimuli, and reduces the interstimulus interval between consecutive APs, consistent with increased neural excitability and altered input/output relationships. Understanding this common pathophysiological mechanism among different voltage-gated ion channels at the circuit level will give insights into the underlying mechanisms of ASD.
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Affiliation(s)
- Ahmed Eltokhi
- Department of Pharmacology, University of Washington, Seattle, WA98195
| | - Brian Nils Lundstrom
- Department of Neurology in the Division of Epilepsy, Mayo Clinic, Rochester, MN55905
| | - Jin Li
- Department of Pharmacology, University of Washington, Seattle, WA98195
| | - Larry S. Zweifel
- Department of Pharmacology, University of Washington, Seattle, WA98195
- Department of Psychiatry & Behavioral Sciences, University of Washington, Seattle, WA98195
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Lin Y, Tao E, Champion JP, Corry B. A binding site for phosphoinositides described by multiscale simulations explains their modulation of voltage-gated sodium channels. eLife 2024; 12:RP91218. [PMID: 38465747 DOI: 10.7554/elife.91218] [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] [Indexed: 03/12/2024] Open
Abstract
Voltage-gated sodium channels (Naᵥ) are membrane proteins which open to facilitate the inward flux of sodium ions into excitable cells. In response to stimuli, Naᵥ channels transition from the resting, closed state to an open, conductive state, before rapidly inactivating. Dysregulation of this functional cycle due to mutations causes diseases including epilepsy, pain conditions, and cardiac disorders, making Naᵥ channels a significant pharmacological target. Phosphoinositides are important lipid cofactors for ion channel function. The phosphoinositide PI(4,5)P2 decreases Naᵥ1.4 activity by increasing the difficulty of channel opening, accelerating fast inactivation and slowing recovery from fast inactivation. Using multiscale molecular dynamics simulations, we show that PI(4,5)P2 binds stably to inactivated Naᵥ at a conserved site within the DIV S4-S5 linker, which couples the voltage-sensing domain (VSD) to the pore. As the Naᵥ C-terminal domain is proposed to also bind here during recovery from inactivation, we hypothesize that PI(4,5)P2 prolongs inactivation by competitively binding to this site. In atomistic simulations, PI(4,5)P2 reduces the mobility of both the DIV S4-S5 linker and the DIII-IV linker, responsible for fast inactivation, slowing the conformational changes required for the channel to recover to the resting state. We further show that in a resting state Naᵥ model, phosphoinositides bind to VSD gating charges, which may anchor them and impede VSD activation. Our results provide a mechanism by which phosphoinositides alter the voltage dependence of activation and the rate of recovery from inactivation, an important step for the development of novel therapies to treat Naᵥ-related diseases.
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Affiliation(s)
- Yiechang Lin
- Research School of Biology, Australian National University, Canberra, Australia
| | - Elaine Tao
- Research School of Biology, Australian National University, Canberra, Australia
| | - James P Champion
- Research School of Biology, Australian National University, Canberra, Australia
| | - Ben Corry
- Research School of Biology, Australian National University, Canberra, Australia
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7
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Bhatia IPS, Hasvi J, Nazneen PS, Rajan A. Hypokalemic Periodic Paralysis: A Rare Case of a Descending Flaccid Paralysis. Cureus 2024; 16:e55981. [PMID: 38606215 PMCID: PMC11007483 DOI: 10.7759/cureus.55981] [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: 02/14/2024] [Accepted: 03/04/2024] [Indexed: 04/13/2024] Open
Abstract
Hypokalemic periodic paralysis (HPP) is an uncommon condition resulting from channelopathy, impacting skeletal muscles. It is distinguished by episodes of sudden and temporary muscle weakness alongside low potassium levels. The normalization of potassium resolves the associated paralysis. Most of these cases are hereditary. Few cases are acquired and are associated with an etiology related to endocrine disorders (e.g., thyrotoxicosis, hyperaldosteronism, and hypercortisolism). It is characterized by acute flaccid paralysis, usually of the ascending type, affecting the proximal region more than the distal region. Herein, we report the case of a 29-year-old male who instead of the ascending type presented with descending-type acute flaccid paralysis. Potassium level at presentation was 1.7 mEq/L. The patient was managed with parenteral and oral potassium supplementation, after which the weakness was completely resolved.
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Affiliation(s)
| | - Jayaraj Hasvi
- Department of Internal Medicine, 167 Military Hospital, Pathankot, IND
| | | | - Amit Rajan
- Department of Lab Sciences and Pathology, 167 Military Hospital, Pathankot, IND
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Wanas AM, Giacuzzo C, Ghazi-Nouri S, Tan LT. Intravenous methylprednisolone-induced hypokalaemic periodic paralysis in a thyrotoxic patient: a case report and literature review. Orbit 2024:1-5. [PMID: 38186318 DOI: 10.1080/01676830.2023.2296553] [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: 10/26/2023] [Accepted: 12/12/2023] [Indexed: 01/09/2024]
Abstract
Hypokalaemic periodic paralysis (HPP) is an uncommon complication of corticosteroid therapy, which may also be seen in thyrotoxicosis. It was mostly described in the Asian population, and it is rare in other ethnic groups. We present the case of a poorly controlled thyrotoxic Caucasian male with thyroid eye disease (TED) who suffered an acute quadriplegic episode caused by severe hypokalaemia and was admitted to the intensive care unit (ITU) within 24 hours of initiating intravenous methylprednisolone (IVMP) infusion. Once his potassium blood levels were repleted, he completely recovered from the episode. Although HPP is rare in the Caucasian population, it can be precipitated in thyrotoxic patients by systemic steroids. Caution should be exercised when administering IVMP in poorly controlled thyrotoxic patients, and we suggest monitoring the potassium levels at regular intervals with ECG monitoring for at least 24 hours in at-risk individuals.
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Affiliation(s)
- Ahmed Magid Wanas
- Department of Ophthalmology, Mid and South Essex NHS Foundation Trust, Essex, UK
| | - Clarice Giacuzzo
- Department of Ophthalmology, Mid and South Essex NHS Foundation Trust, Essex, UK
| | - Seyed Ghazi-Nouri
- Department of Ophthalmology, Mid and South Essex NHS Foundation Trust, Essex, UK
| | - Lee Teak Tan
- Department of Ophthalmology, Mid and South Essex NHS Foundation Trust, Essex, UK
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9
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Sara S, Tv D, Dg G, Elumalai B, Javid M. A Rare Case of Hypokalemic Periodic Paralysis With Acute Urinary Retention: Diagnosis and Management. Cureus 2024; 16:e52839. [PMID: 38406120 PMCID: PMC10884782 DOI: 10.7759/cureus.52839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/23/2024] [Indexed: 02/27/2024] Open
Abstract
Hypokalemic periodic paralysis (hypoPP) is a rare channelopathy caused by mutations in skeletal muscle ion channels that usually occurs in young individuals and adolescents. The etiology can be attributed to various factors, such as idiopathic or secondary causes. It is characterized by episodes of sudden flaccid muscle weakness. Timely detection may mitigate the risk of severe complications. Secondary causes of hypoPP, such as hyperthyroidism, should be ruled out, as this could lead to thyrotoxic periodic paralysis. We report the case of a 19-year-old boy who presented to the ED with severe weakness in both the upper and lower extremities. The weakness rapidly progressed to his trunk and was accompanied by acute urinary retention. The physical examination was significant for bilateral upper and lower extremity weakness. Subsequent laboratory investigations revealed markedly low serum potassium levels. The patient's symptoms resolved after the replacement of potassium, and he was discharged without neurological deficits. Although rarely accompanied by acute urinary retention, hypoPP must be differentiated from other causes of weakness and paralysis so that the proper treatment can be initiated quickly. The rarity of hypoPP, a condition seldom encountered in clinical practice, and the added rarity of its coexistence with acute urinary retention further underscore the uniqueness of this case report.
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Affiliation(s)
- S Sara
- Internal Medicine, Public Health Centre, Chennai, IND
| | - Dhigvijay Tv
- General Surgery, Sri Saraswathi Hospital and Surgical Center, Krishnagiri, IND
| | - Gokulesh Dg
- Internal Medicine, Madras Medical College, Chennai, IND
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10
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Arcos-Hernández C, Nishigaki T. Ion currents through the voltage sensor domain of distinct families of proteins. J Biol Phys 2023; 49:393-413. [PMID: 37851173 PMCID: PMC10651576 DOI: 10.1007/s10867-023-09645-z] [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: 04/28/2023] [Accepted: 09/11/2023] [Indexed: 10/19/2023] Open
Abstract
The membrane potential of a cell (Vm) regulates several physiological processes. The voltage sensor domain (VSD) is a region that confers voltage sensitivity to different types of transmembrane proteins such as the following: voltage-gated ion channels, the voltage-sensing phosphatase (Ci-VSP), and the sperm-specific Na+/H+ exchanger (sNHE). VSDs contain four transmembrane segments (S1-S4) and several positively charged amino acids in S4, which are essential for the voltage sensitivity of the protein. Generally, in response to changes of the Vm, the positive residues of S4 displace along the plasma membrane without generating ionic currents through this domain. However, some native (e.g., Hv1 channel) and mutants of VSDs produce ionic currents. These gating pore currents are usually observed in VSDs that lack one or more of the conserved positively charged amino acids in S4. The gating pore currents can also be induced by the isolation of a VSD from the rest of the protein domains. In this review, we summarize gating pore currents from all families of proteins with VSDs with classification into three cases: (1) pathological, (2) physiological, and (3) artificial currents. We reinforce the model in which the position of S4 that lacks the positively charged amino acid determines the voltage dependency of the gating pore current of all VSDs independent of protein families.
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Affiliation(s)
- César Arcos-Hernández
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, 62210, Mexico.
| | - Takuya Nishigaki
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, 62210, Mexico
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11
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Adjei P, Amponsah GM, Atenebano M. An unusual stroke mimic: A case report. SAGE Open Med Case Rep 2023; 11:2050313X231209686. [PMID: 37941981 PMCID: PMC10629323 DOI: 10.1177/2050313x231209686] [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: 06/24/2023] [Accepted: 10/06/2023] [Indexed: 11/10/2023] Open
Abstract
Hypokalaemic paralysis is a rare disorder characterized by rapid onset of symmetrical flaccid skeletal muscle weakness in the presence of reduced serum potassium levels. It is categorized as primary or secondary depending on the aetiology. Asymmetric or unilateral muscle weakness in hypokalaemic patients is a rare presentation. In patients with comorbid cardiovascular risk factors, this atypical manifestation can mimic acute stroke. Only a few of such cases have been reported in the literature. This report discusses the case of a 46-year-old hypertensive Ghanaian woman who presented to a District Hospital with sudden-onset right-sided flaccid weakness and a high blood pressure. Acute stroke was ruled out with computed tomography scan of the brain. Further laboratory evaluation demonstrated reduced serum potassium level, which was corrected with subsequent dramatic resolution of the muscle weakness.
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Affiliation(s)
- Prosper Adjei
- Department of Medicine, Methodist Hospital, Wenchi, Ghana
| | - Gordon M Amponsah
- Department of Physiology, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
- Directorate of Internal Medicine, Komfo Anokye Teaching Hospital, Kumasi, Ghana
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12
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Noor S, Rasooly AJ, Alikozai SM, Jalalzai T, Haidary AM, Nasir N, Noor S, Farooqi M, Mansoori H. Hypokalemic periodic paralysis in a teenage boy after an intense period of exercise: A rare case report. Clin Case Rep 2023; 11:e8201. [PMID: 38028058 PMCID: PMC10645604 DOI: 10.1002/ccr3.8201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 10/19/2023] [Accepted: 10/30/2023] [Indexed: 12/01/2023] Open
Abstract
Key Clinical Messages Diagnosis of rare even can be missed due to less familiarity with the disorder.In patients with muscle weakness, infectious causes are prioritized.Electrolyte profile not only identifies the problem, but also prevents unnecessary workup. Abstract In underdeveloped countries, diagnosis of rare disorders is usually delayed due to less familiarity of the clinicians to such disorders. As a result, infectious and inflammatory causes for an ailment are prioritized as compared to non-infectious etiologies. Hypokalemic periodic paralysis (PP) is a rare disorder, characterized by episodic muscle weakness that can rarely be associated with life-threatening cardiac arrhythmia. A teenage Afghan boy presented to the emergency department with an acute flaccid paralysis, that started 1 h after intense exercise The weakness involved both, the upper and lower extremities. Laboratory investigations, led to the impression of hypokalemic PP, precipitated by intense exercise. Accordingly, intravenous potassium chloride infusion diluted with normal saline led to the complete resolution of paralysis as well as correction of electrocardiographic changes. The list of differential diagnosis for flaccid muscle paralysis is wide, which generally requires a extensive investigations, but in hypokalemic PP, a cardinal electrolytes profile can lead towards early diagnosis. High degree of clinical suspicion with appropriate history taking and physical examination helps with the immediate identification and management of this disorder.
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Affiliation(s)
- Sahar Noor
- Department of Pediatrics MedicineFrench Medical Institute for Mothers and Children (FMIC)KabulAfghanistan
| | - Abdul Jamil Rasooly
- Department of Pediatrics MedicineFrench Medical Institute for Mothers and Children (FMIC)KabulAfghanistan
| | - Sultan Mahmood Alikozai
- Department of Pediatrics MedicineFrench Medical Institute for Mothers and Children (FMIC)KabulAfghanistan
| | - Tooryalai Jalalzai
- Department of Pediatrics MedicineFrench Medical Institute for Mothers and Children (FMIC)KabulAfghanistan
| | - Ahmed Maseh Haidary
- Department of PathologyFrench Medical Institute for Mothers and Children (FMIC)KabulAfghanistan
| | - Najla Nasir
- Department of MedicineRabia Balkhi HospitalKabulAfghanistan
| | - Sarah Noor
- Department of Hemato‐OncologyAli Abad Teaching HospitalKabulAfghanistan
| | - Masooma Farooqi
- Department of CardiologyFrench Medical Institute for Mothers and Children (FMIC)KabulAfghanistan
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13
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Schulte K, Sheedy M, Feustel K, Scherbak D. Newly Diagnosed Hypokalemic Periodic Paralysis Triggered by COVID-19. Cureus 2023; 15:e47906. [PMID: 38034179 PMCID: PMC10683774 DOI: 10.7759/cureus.47906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/28/2023] [Indexed: 12/02/2023] Open
Abstract
Hypokalemic periodic paralysis (HypoPP) is a rare genetic disorder characterized by low potassium levels and episodic periods of muscle weakness. HypoPP has previously been attributed to numerous viral infections; however, cases related to coronavirus disease 2019 (COVID-19) are extremely limited. The current case is thus unique and involves a healthy 23-year-old male who presented to the emergency department after several uncharacteristic falls and three days of upper and lower extremity weakness. Initial labs revealed a potassium level of 1.1 mmol/L as well as being COVID-19 positive. Potassium supplementation helped stabilize his levels and relieved all of his symptoms. Based on an extensive clinical workup and significant family history of the mother and maternal grandmother with weakness in the setting of hypokalemia, a diagnosis of HypoPP was made. Upon discharge, he was placed on potassium-sparing diuretics to help prevent further symptom relapse and advised to complete genetic testing. With the high likelihood of the virus being endemic for years to come, clinicians should remember to consider HypoPP with patients with muscle weakness, especially in patients with concurrent COVID-19 infection, to minimize unnecessary workup and prevent potentially life-threatening symptoms of hypokalemia.
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Affiliation(s)
- Kelly Schulte
- Internal Medicine, Sky Ridge Medical Center, Lone Tree, USA
| | - Maxwell Sheedy
- Internal Medicine, Rocky Vista University College of Osteopathic Medicine, Parker, USA
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14
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Nuzhnyi EP, Arestova AS, Rossokhin AV, Protopopova AO, Abramycheva NY, Suponeva NA, Illarioshkin SN. Case report: A novel CACNA1S mutation associated with hypokalemic periodic paralysis. Front Neurol 2023; 14:1267426. [PMID: 37840943 PMCID: PMC10570449 DOI: 10.3389/fneur.2023.1267426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 09/14/2023] [Indexed: 10/17/2023] Open
Abstract
Background Hypokalemic periodic paralysis (HypoKPP) is a rare neuromuscular genetic disorder causing recurrent episodes of flaccid paralysis. Most cases are associated with CACNA1S mutation, causing defect of calcium channel and subsequent impairment of muscle functions. Due to defined management approaches early diagnosis is crucial for promptly treatment and prevention new attacks. Materials and methods We report a case of HypoKPP associated with previously unreported mutation in CACNA1S gene (p.R900M). Molecular modeling of CaV1.1 was applied to evaluate its pathogenicity. Results As a patient referred between attacks neurological status, laboratory and neurophysiological examination were unremarkable. Molecular modeling predicted that the p.R900M mutation affects the process of calcium channels activation. Conclusion Novel CACNA1S mutation, associated with HypoKPP was identified. Monte-Carlo energy minimization of the CaV1.1 model supported the association of this mutation with this disease.
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15
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Catacuzzeno L, Conti F, Franciolini F. Fifty years of gating currents and channel gating. J Gen Physiol 2023; 155:e202313380. [PMID: 37410612 PMCID: PMC10324510 DOI: 10.1085/jgp.202313380] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 05/12/2023] [Accepted: 06/02/2023] [Indexed: 07/08/2023] Open
Abstract
We celebrate this year the 50th anniversary of the first electrophysiological recordings of the gating currents from voltage-dependent ion channels done in 1973. This retrospective tries to illustrate the context knowledge on channel gating and the impact gating-current recording had then, and how it continued to clarify concepts, elaborate new ideas, and steer the scientific debate in these 50 years. The notion of gating particles and gating currents was first put forward by Hodgkin and Huxley in 1952 as a necessary assumption for interpreting the voltage dependence of the Na and K conductances of the action potential. 20 years later, gating currents were actually recorded, and over the following decades have represented the most direct means of tracing the movement of the gating charges and gaining insights into the mechanisms of channel gating. Most work in the early years was focused on the gating currents from the Na and K channels as found in the squid giant axon. With channel cloning and expression on heterologous systems, other channels as well as voltage-dependent enzymes were investigated. Other approaches were also introduced (cysteine mutagenesis and labeling, site-directed fluorometry, cryo-EM crystallography, and molecular dynamics [MD] modeling) to provide an integrated and coherent view of voltage-dependent gating in biological macromolecules. The layout of this retrospective reflects the past 50 years of investigations on gating currents, first addressing studies done on Na and K channels and then on other voltage-gated channels and non-channel structures. The review closes with a brief overview of how the gating-charge/voltage-sensor movements are translated into pore opening and the pathologies associated with mutations targeting the structures involved with the gating currents.
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Affiliation(s)
- Luigi Catacuzzeno
- Department of Chemistry Biology and Biotechnology, University of Perugia, Perugia, Italy
| | - Franco Conti
- Department of Physics, University of Genova, Genova, Italy
| | - Fabio Franciolini
- Department of Chemistry Biology and Biotechnology, University of Perugia, Perugia, Italy
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16
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Vicino A, Brugnoni R, Maggi L. Diagnostics in skeletal muscle channelopathies. Expert Rev Mol Diagn 2023; 23:1175-1193. [PMID: 38009256 DOI: 10.1080/14737159.2023.2288258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Accepted: 11/22/2023] [Indexed: 11/28/2023]
Abstract
INTRODUCTION Skeletal muscle channelopathies (SMCs) are a heterogenous group of disorders, caused by mutations in skeletal ion channels leading to abnormal muscle excitability, resulting in either delayed muscle relaxation (myotonia) which characterizes non-dystrophic myotonias (NDMs), or membrane transient inactivation, causing episodic weakness, typical of periodic paralyses (PPs). AREAS COVERED SMCs include myotonia congenita, paramyotonia congenita, and sodium-channel myotonia among NDMs, and hyper-normokalemic, hypokalemic, or late-onset periodic paralyses among PPs. When suspecting an SMC, a structured diagnostic approach is required. Detailed personal and family history and clinical examination are essential, while neurophysiological tests should confirm myotonia and rule out alternative diagnosis. Moreover, specific electrodiagnostic studies are important to further define the phenotype of de novo cases and drive molecular analyses together with clinical data. Definite diagnosis is achieved through genetic testing, either with Sanger sequencing or multigene next-generation sequencing panel. In still unsolved patients, more advanced techniques, as exome-variant sequencing or whole-genome sequencing, may be considered in expert centers. EXPERT OPINION The diagnostic approach to SMC is still mainly based on clinical data; moreover, definite diagnosis is sometimes complicated by the difficulty to establish a proper genotype-phenotype correlation. Lastly, further studies are needed to allow the genetic characterization of unsolved patients.
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Affiliation(s)
- Alex Vicino
- Neurology IV Unit, Neuroimmunology and Neuromuscular Diseases, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
- Nerve-Muscle Unit, Neurology Service, Department of Clinical Neurosciences, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Raffaella Brugnoni
- Neurology IV Unit, Neuroimmunology and Neuromuscular Diseases, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Lorenzo Maggi
- Neurology IV Unit, Neuroimmunology and Neuromuscular Diseases, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
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17
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Mebane NB, Khan A, Bevinal M, Davis E. Thyrotoxic Periodic Paralysis With Hypokalemia: A Case Study. Cureus 2023; 15:e40757. [PMID: 37485151 PMCID: PMC10361783 DOI: 10.7759/cureus.40757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/21/2023] [Indexed: 07/25/2023] Open
Abstract
Thyrotoxic periodic paralysis (TPP) is a rare life-threatening condition most commonly seen in individuals between the ages of 20-40 years. It is most prevalent in Hispanic and Asian populations. Here we present a case report of a young male patient admitted to our facility with an acute onset of paralysis. He was found to have new-onset hyperthyroidism and severe hypokalemia. TPP was exacerbated by the intake of a high-carbohydrate meal as well as a steroid injection within 24 hours of symptom onset.
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Affiliation(s)
- Nova B Mebane
- Internal Medicine, Corpus Christi Medical Center, Corpus Christi, USA
| | - Aisha Khan
- Internal Medicine, Corpus Christi Medical Center, Corpus Christi, USA
| | - Manzoor Bevinal
- Internal Medicine, Corpus Christi Medical Center, Corpus Christi, USA
| | - Erin Davis
- Internal Medicine, Texas College of Osteopathic Medicine, Fort Worth, USA
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18
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Yahya AMB, Ahmed N, Qayyum H. An Interesting Case of Weakness and Atrial Tachycardia in the Emergency Department: Thinking Beyond Hearts and Minds. Cureus 2023; 15:e38002. [PMID: 37155518 PMCID: PMC10122726 DOI: 10.7759/cureus.38002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/23/2023] [Indexed: 05/10/2023] Open
Abstract
Thyrotoxic periodic paralysis is a rare but life-threatening presentation of hyperthyroidism that manifests with sudden, painless episodes of muscle weakness due to hypokalemia. We present the case of a middle-aged Middle Eastern female who attended our Emergency Department with sudden onset weakness to the lower limbs, resulting in her inability to walk. She had a power of 1/5 in the lower limbs, and subsequent investigations showed a low potassium level, and primary hyperthyroidism secondary to Grave's disease was diagnosed. A 12-lead electrocardiogram showed atrial flutter with a variable block, along with U waves. The patient reverted to sinus rhythm following administration of potassium replacement and was also treated with Propanalol and Carbimazole. The patient made a full neurological recovery. Emergency physicians and all frontline healthcare workers should be aware that electrolyte problems can cause paralysis. Furthermore, hypokalemic periodic paralysis can be caused by an undiagnosed thyrotoxic state. Be aware that if left untreated, hypokalemia can cause serious atrial and ventricular arrhythmias. Achieving a euthyroid state and blunting hyperadrenergic stimulation, in addition to replacing potassium, all help to fully reverse muscle weakness.
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Affiliation(s)
| | - Nasser Ahmed
- Emergency Department, Sheikh Khalifa Medical City, Abu Dhabi, ARE
| | - Hasan Qayyum
- Emergency Department, Sheikh Khalifa Medical City, Abu Dhabi, ARE
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19
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Tai HT, Lee PT, Ou SH. Steroid-induced hypokalemic periodic paralysis: a case report and literature review. BMC Nephrol 2023; 24:70. [PMID: 36964512 PMCID: PMC10039554 DOI: 10.1186/s12882-023-03131-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 03/20/2023] [Indexed: 03/26/2023] Open
Abstract
BACKGROUND Hypokalemic periodic paralysis (HPP) is a rare channelopathy characterized by episodic attacks of acute muscle weakness concomitant with hypokalemia. The etiology of hypokalemia is the shift of potassium into the cells, and the clinical symptoms resolve when potassium starts to leak back to the serum. Most of the time, the underlying ion channel defects are well compensated, and an additional trigger is often required to initiate an attack. Well-known trigger factors include carbohydrate-rich meals, exercise followed by rest, stress, cold weather, and alcohol consumption. CASE PRESENTATION Here, we present the case of a 26-year-old Asian man who suffered from an acute onset of bilateral lower limb weakness with hypokalemia following dexamethasone injection. He was diagnosed with HPP. CONCLUSIONS We would like to remind physicians to think of steroids as an unusual precipitating factor while managing patients with HPP, per results of this case study.
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Affiliation(s)
- Haw-Ting Tai
- Division of Nephrology, Department of Internal Medicine, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan
- Faculty of Medicine, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Po-Tsang Lee
- Division of Nephrology, Department of Internal Medicine, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan
- Faculty of Medicine, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Shih-Hsiang Ou
- Division of Nephrology, Department of Internal Medicine, Pingtung Veterans General Hospital, No. 1, Rongzong E. Rd., Pingtung County, 900010, Pingtung City, Taiwan (R.O.C.).
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20
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Allard M, Barrallier M, Pisaroni H, Fichet M, De La Vergne De Cerval M, Pflaum R, Poisson A, Derrien C, Bonnet F, Vaduva P. Thyrotoxic periodic paralysis associated with lactic metabolic acidosis: Case report of an African man and review of literature. ANNALES D'ENDOCRINOLOGIE 2023:S0003-4266(23)00030-6. [PMID: 36758896 DOI: 10.1016/j.ando.2023.01.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 12/29/2022] [Accepted: 01/30/2023] [Indexed: 02/10/2023]
Abstract
BACKGROUND Thyrotoxic periodic paralysis (TPP) is a rare and most often acquired subtype of hypokalemic periodic paralysis. The association of varying degrees of muscle weakness, hyperthyroidism and hypokalemia characterizes it. The treatment requires potassium supplementation, control of hyperthyroidism and prevention measures. It is a frequent disease in Asian men, but much rare in Caucasian or African populations. This is the first report of TPP associated with lactic metabolic acidosis in an African man. CASE PRESENTATION A 23 year-old African man, native from Morocco, with recurrent episodes of tetraparesis for eleven months, and abdominal pain, was referred for evaluation. Biochemical investigations showed severe hypokalemia associated with hyperthyroidism and lactic metabolic acidosis. His EKG showed signs of hypokalemia such as sinus tachycardia and U waves. After potassium supplementation, neurological recuperation was quick and complete. Thyroid ultrasound identified a hypoechogenic and hypervascularized goiter, associated with high levels of thyroid antibodies, in favor of Grave's disease. With antithyroid drugs and life-style changes, the patient did not have any other attack. REVIEW OF LITERATURE In addition to the case report, this article presents an extended review of literature, from the first large study reporting the diagnosis and incidence of TPP in 1957 to nowadays. Are reported here the latest information concerning epidemiology, clinical manifestations, complementary examinations, management and genetic finding. The lactic acidosis observed initially is exceptional, never described in TPP. TPP is a diagnostic and therapeutic emergency, requiring careful potassium supplementation, in order to avoid the risk of the onset of rebound hyperkalemia, to be maintained until the etiological treatment is effective. Paraclinical assessment with emergency EKG and electromyogram are essential to assess the impact. DISCUSSION It is essential in the face of any hypokalaemic periodic paralysis, including in non-Asian subjects, to search hyperthyroidism. CONCLUSIONS This report demonstrates the importance of thyroid testing in case of acute muscle weakness, even in non-Asian patients in order to diagnose TPP. This is a rare but possible etiology, to be distinguished from the familial form of hypokalemic periodic paralysis. It also questions on the impact of TPP on energetic metabolism, in particular on lactic metabolism.
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Affiliation(s)
- Maurine Allard
- Department of Endocrinology, University Hospital of Rennes, Rennes, France.
| | | | - Hugo Pisaroni
- Department of Endocrinology, University Hospital of Rennes, Rennes, France
| | - Mathilde Fichet
- Department of Endocrinology, University Hospital of Rennes, Rennes, France
| | | | - Robin Pflaum
- Department of Endocrinology, University Hospital of Rennes, Rennes, France
| | - Audrey Poisson
- Department of Endocrinology, University Hospital of Rennes, Rennes, France
| | - Christèle Derrien
- Department of Endocrinology, University Hospital of Rennes, Rennes, France
| | - Fabrice Bonnet
- Department of Endocrinology, University Hospital of Rennes, Rennes, France
| | - Patricia Vaduva
- Department of Endocrinology, University Hospital of Rennes, Rennes, France
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21
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Park S, Heo W, Shin SW, Kim HJ, Yoo YM, Kim HY. General anesthesia using propofol infusion for implantation of an implantable cardioverter defibrillator in a pediatric patient with Andersen-Tawil syndrome: a case report. J Dent Anesth Pain Med 2023; 23:45-51. [PMID: 36819605 PMCID: PMC9911964 DOI: 10.17245/jdapm.2023.23.1.45] [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: 10/18/2022] [Revised: 12/04/2022] [Accepted: 12/11/2022] [Indexed: 02/05/2023] Open
Abstract
Andersen-Tawil syndrome (ATS) is a rare genetic disease characterized by a triad of episodic flaccid muscle weakness, ventricular arrhythmias, and physical anomalies. ATS patients have various cardiac arrhythmias that can cause sudden death. Implantation of an implantable cardioverter-defibrillator (ICD) is required when life-threatening cardiac arrhythmias do not respond to medical treatment. An 11-year-old girl underwent surgery for an ICD implantation. For general anesthesia in ATS patients, anesthesiologists should focus on the potentially difficult airway, serious cardiac arrhythmias, such as ventricular tachycardia (VT), and delayed recovery from neuromuscular blockade. We followed the difficult airway algorithm, avoided drugs that can precipitate QT prolongation and fatal cardiac arrhythmias, and tried to maintain normoxia, normocarbia, normothermia, normoglycemia, and pain control for prevention of sympathetic stimulation. We report the successful application of general anesthesia for ICD implantation in a pediatric patient with ATS and recurrent VT.
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Affiliation(s)
- Seyeon Park
- Department of Anesthesia and Pain Medicine, Pusan National University Yangsan Hospital, Yangsan, Republic of Korea
| | - Wonjae Heo
- Department of Anesthesia and Pain Medicine, Pusan National University Yangsan Hospital, Yangsan, Republic of Korea
| | - Sang-Wook Shin
- Department of Anesthesia and Pain Medicine, Pusan National University Yangsan Hospital, Yangsan, Republic of Korea.,Department of Anesthesia and Pain Medicine, School of Medicine, Pusan National University, Yangsan, Republic of Korea
| | - Hye-Jin Kim
- Department of Anesthesia and Pain Medicine, Pusan National University Yangsan Hospital, Yangsan, Republic of Korea
| | - Yeong Min Yoo
- Department of Anesthesia and Pain Medicine, Pusan National University Yangsan Hospital, Yangsan, Republic of Korea
| | - Hee Young Kim
- Department of Anesthesia and Pain Medicine, Pusan National University Yangsan Hospital, Yangsan, Republic of Korea.,Department of Anesthesia and Pain Medicine, School of Medicine, Pusan National University, Yangsan, Republic of Korea
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22
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Quiñonez M, DiFranco M, Wu F, Cannon SC. Retigabine suppresses loss of force in mouse models of hypokalaemic periodic paralysis. Brain 2023; 146:1554-1560. [PMID: 36718088 PMCID: PMC10115351 DOI: 10.1093/brain/awac441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2022] [Revised: 10/18/2022] [Accepted: 11/12/2022] [Indexed: 02/01/2023] Open
Abstract
Recurrent episodes of weakness in periodic paralysis are caused by intermittent loss of muscle fibre excitability, as a consequence of sustained depolarization of the resting potential. Repolarization is favoured by increasing the fibre permeability to potassium. Based on this principle, we tested the efficacy of retigabine, a potassium channel opener, to suppress the loss of force induced by a low-K+ challenge in hypokalaemic periodic paralysis (HypoPP). Retigabine can prevent the episodic loss of force in HypoPP. Knock-in mutant mouse models of HypoPP (Cacna1s p.R528H and Scn4a p.R669H) were used to determine whether pre-treatment with retigabine prevented the loss of force, or post-treatment hastened recovery of force for a low-K+ challenge in an ex vivo contraction assay. Retigabine completely prevents the loss of force induced by a 2 mM K+ challenge (protection) in our mouse models of HypoPP, with 50% inhibitory concentrations of 0.8 ± 0.13 μM and 2.2 ± 0.42 μM for NaV1.4-R669H and CaV1.1-R528H, respectively. In comparison, the effective concentration for the KATP channel opener pinacidil was 10-fold higher. Application of retigabine also reversed the loss of force (rescue) for HypoPP muscle maintained in 2 mM K+. Our findings show that retigabine, a selective agonist of the KV7 family of potassium channels, is effective for the prevention of low-K+ induced attacks of weakness and to enhance recovery from an ongoing loss of force in mouse models of type 1 (Cacna1s) and type 2 (Scn4a) HypoPP. Substantial protection from the loss of force occurred in the low micromolar range, well within the therapeutic window for retigabine.
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Affiliation(s)
- Marbella Quiñonez
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Marino DiFranco
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Fenfen Wu
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Stephen C Cannon
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA.,Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
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23
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Zhang Z, Xiao B. Case report: SCN4A p.R1135H gene variant in combination with thyrotoxicosis causing hypokalemic periodic paralysis. Front Neurol 2023; 13:1078784. [PMID: 36733446 PMCID: PMC9886676 DOI: 10.3389/fneur.2022.1078784] [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: 11/17/2022] [Accepted: 12/28/2022] [Indexed: 01/18/2023] Open
Abstract
Hypokalemic periodic paralysis (HPP) is a heterogeneous group of diseases characterized by intermittent episodes of delayed paralysis of skeletal muscle with episodes of hypokalemia, caused by variants in CACNA1S or SCN4A genes, or secondary to thyrotoxicosis, Sjogren syndrome, primary aldosteronism, etc. HPP may be the only presentation in Andersen-Tawil syndrome in which the majority of cases are caused by pathogenic variants in the KCNJ2 gene. We present a case of a 29-year-old male with hypokalemic periodic paralysis. The patient began to experience recurrent weakness of the extremities at the age of 26, which was effectively treated with potassium supplementation. He had recently developed dry mouth, palpitations, weight loss, and even dyspnea, with a serum potassium level as low as 1.59 mmol/L. The results of auxiliary examinations showed Graves' disease, and genetic testing indicated a missense variant, NM_000334.4 (SCN4A):c.3404G>A (p.R1135H). He did not experience periodic paralysis during follow-up after lifestyle guidance and treatment of thyrotoxicosis with radioactive iodine. It is a rare case of SCN4A p.R1135H gene variant combined with hyperthyroidism resulting in HPP with respiratory muscle paralysis to raise awareness of the disease and avoid misdiagnosis and missed diagnosis.
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24
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Pathophysiologic approach in genetic hypokalemia: An update. ANNALES D'ENDOCRINOLOGIE 2023; 84:298-307. [PMID: 36639120 DOI: 10.1016/j.ando.2022.11.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Accepted: 11/30/2022] [Indexed: 01/12/2023]
Abstract
The pathophysiology of genetic hypokalemia is close to that of non-genetic hypokalemia. New molecular pathways physiologically involved in renal and extrarenal potassium homeostasis have been highlighted. A physiological approach to diagnosis is illustrated here, with 6 cases. Mechanisms generating and sustaining of hypokalemia are discussed. After excluding acute shift of extracellular potassium to the intracellular compartment, related to hypokalemic periodic paralysis, inappropriate kaliuresis (>40mmol/24h) concomitant to hypokalemia indicates renal potassium wasting. Clinical analysis distinguishes hypertension-associated hypokalemia, due to hypermineralocorticism or related disorders. Genetic hypertensive hypokalemia is rare. It includes familial hyperaldosteronism, Liddle syndrome, apparent mineralocorticoid excess,11beta hydroxylase deficiency and Geller syndrome. In case of normo- or hypo-tensive hypokalemia, two etiologies are to be considered: chloride depletion or salt-wasting tubulopathy. Diarrhea chlorea is a rare disease responsible for intestinal chloride depletion. Due to the severity of hypokalemic metabolic alkalosis, this disease can be misdiagnosed as pseudo-Bartter syndrome. Gitelman syndrome is the most frequent cause of genetic hypokalemia. It typically associates renal sodium and potassium wasting, hypomagnesemia, conserved chloride excretion (>40mmol/24h), and low-range calcium excretion (urinary Ca/creatinine ratio<0.20mmol/mmol). Systematic analysis of hydroelectrolytic disorder and dynamic hormonal investigation optimizes indications for and orientation of genotyping of hereditary salt-losing tubulopathy.
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25
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Nadeem S, Aziz A, Ali D. Thyrotoxic Periodic Paralysis: A case report. JOURNAL OF CLINICAL AND TRANSLATIONAL ENDOCRINOLOGY CASE REPORTS 2022. [DOI: 10.1016/j.jecr.2022.100122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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26
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Manuel AIM, Gutiérrez LK, Pedrosa MLV, Uréndez FMC, Jiménez FJB, Carrascoso IM, Pérez PS, Macías Á, Jalife J. Molecular stratification of arrhythmogenic mechanisms in the Andersen Tawil Syndrome. Cardiovasc Res 2022; 119:919-932. [PMID: 35892314 PMCID: PMC10153646 DOI: 10.1093/cvr/cvac118] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 06/20/2022] [Accepted: 07/01/2022] [Indexed: 11/12/2022] Open
Abstract
Andersen Tawil Syndrome (ATS) is a rare inheritable disease associated with loss-of-function mutations in KCNJ2, the gene coding the strong inward rectifier potassium channel Kir2.1, which forms an essential membrane protein controlling cardiac excitability. ATS is usually marked by a triad of periodic paralysis, life-threatening cardiac arrhythmias and dysmorphic features, but its expression is variable and not all patients with a phenotype linked to ATS have a known genetic alteration. The mechanisms underlying this arrhythmogenic syndrome are poorly understood. Knowing such mechanisms would be essential to distinguish ATS from other channelopathies with overlapping phenotypes and to develop individualized therapies. For example, the recently suggested role of Kir2.1 as a countercurrent to sarcoplasmic calcium reuptake might explain the arrhythmogenic mechanisms of ATS and its overlap with catecholaminergic polymorphic ventricular tachycardia (CPVT). Here we summarize current knowledge on the mechanisms of arrhythmias leading to sudden cardiac death in ATS. We first provide an overview of the syndrome and its pathophysiology, from the patient´s bedside to the protein, and discuss the role of essential regulators and interactors that could play a role in cases of ATS. The review highlights novel ideas related to some post-translational channel interactions with partner proteins that might help define the molecular bases of the arrhythmia phenotype. We then propose a new all-embracing classification of the currently known ATS loss-of-function mutations according to their position in the Kir2.1 channel structure and their functional implications. We also discuss specific ATS pathogenic variants, their clinical manifestations and treatment stratification. The goal is to provide a deeper mechanistic understanding of the syndrome toward the development of novel targets and personalized treatment strategies.
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Affiliation(s)
| | - Lilian K Gutiérrez
- Centro Nacional de Investigaciones Cardiovasculares (CNIC) Carlos III, 28029 Madrid, Spain
| | | | | | - Francisco José Bermúdez Jiménez
- Centro Nacional de Investigaciones Cardiovasculares (CNIC) Carlos III, 28029 Madrid, Spain.,Departamento de Cardiología, Hospital Virgen de las Nieves, GranadaSpain
| | | | - Patricia Sánchez Pérez
- Centro Nacional de Investigaciones Cardiovasculares (CNIC) Carlos III, 28029 Madrid, Spain
| | - Álvaro Macías
- Centro Nacional de Investigaciones Cardiovasculares (CNIC) Carlos III, 28029 Madrid, Spain
| | - José Jalife
- Centro Nacional de Investigaciones Cardiovasculares (CNIC) Carlos III, 28029 Madrid, Spain.,CIBER de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain.,Departments of Medicine and Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
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27
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Sharif S, Tang J. Potassium Derangements: A Pathophysiological Review, Diagnostic Approach, and Clinical Management. Physiology (Bethesda) 2022. [DOI: 10.5772/intechopen.103016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Potassium is an essential cation critical in fluid and electrolyte balance, acid–base regulation, and neuromuscular functions. The normal serum potassium is kept within a narrow range of 3.5–5.2 meq/L while the intracellular concentration is approximately 140–150 meq/L. The total body potassium is about 45–55 mmol/kg; thus, a 70 kg male has an estimated ~136 g and 60 kg female has ~117 g of potassium. In total, 98% of the total body potassium is intracellular. Skeletal muscle contains ~80% of body potassium stores. The ratio of intracellular to extracellular potassium concentration (Ki/Ke) maintained by Na+/K+ ATPase determines the resting membrane potential. Disturbances of potassium homeostasis lead to hypo- and hyperkalemia, which if severe, can be life-threatening. Prompt diagnosis and management of these problems are important.
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28
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Hati A, Chakraborty U, Chandra A, Biswas P. Hypokalaemia with Guillain-Barré syndrome: a diagnostic and therapeutic challenge. BMJ Case Rep 2022; 15:e249473. [PMID: 35760510 PMCID: PMC9237892 DOI: 10.1136/bcr-2022-249473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/14/2022] [Indexed: 11/03/2022] Open
Abstract
Acute-onset quadriparesis is not only debilitating and a grave concern for the patient but also perturbs the clinician as it demands early diagnosis and prompt management to prevent catastrophic outcome due to respiratory failure. Guillain-Barré syndrome (GBS) and hypokalaemia are notorious causes of acute-onset lower motor neuron (LMN) quadriparesis and warrant a rapid evaluation to necessitate early management. However, coexistence of these two entities is extremely rare and may pose a diagnostic and therapeutic challenge and mandates exclusion of either condition to avoid a poor outcome. We hereby report a case of a young woman who presented with an acute-onset LMN quadriparesis, initially found to have significant hypokalaemia with poor response to supplementation and was further evaluated to have an axonal variant of GBS.
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Affiliation(s)
- Arkapravo Hati
- Internal Medicine, RG Kar Medical College and Hospital, Kolkata, West Bengal, India
| | - Uddalak Chakraborty
- Neurology, Institute of Postgraduate Medical Education and Research Bangur Institute of Neurology, Kolkata, India
| | - Atanu Chandra
- Internal Medicine, RG Kar Medical College and Hospital, Kolkata, West Bengal, India
| | - Purbasha Biswas
- Internal Medicine, RG Kar Medical College and Hospital, Kolkata, West Bengal, India
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PoudelJaishi P, Neupane SK, Neupane PK. Case report: Hyperthyroid hypokalemic periodic paralysis. Ann Med Surg (Lond) 2022; 78:103759. [PMID: 35620041 PMCID: PMC9127175 DOI: 10.1016/j.amsu.2022.103759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 05/04/2022] [Accepted: 05/08/2022] [Indexed: 11/20/2022] Open
Abstract
Introduction and importance HHPP is a rare type of hypokalemic PP that can occur when there is hyperthyroidism.Thyrotoxic periodic paralysis is due to increased influx of potassium into skeletal muscle cells which leads to profound hypokalemia and paralysis. Insulin and Epinephrine are also responsible for stimulating the Na–K-ATPase pumps which are over expressed during hyperthyroid state. Laboratory hypokalemia in the background of hyperthyroidism with sudden symmetric paralysis point toward the diagnosis. Case We present a case of 25 year old male with limb weakness for 3hours following heavy dinner.He felt weakness after waking up in the morning where he could not move his both lower limbs. He also had difficulty moving upper limbs. Clinical findings and investigations Examination revealed proximal muscle weakness with power of 2/5, decreased muscle tone, diminished deep tendon reflexes in all four limbs and equivocal plantar reflex bilaterally. Investigation sent were Total Leukocyte count, Hemoglobin, Renal function test, Liver Function test,Thyroid function test, Vitamin B12, Serology, ACTH, Serum calcium, Serum phosphate, Serum magnesium, Urine R/ME and Stool R/ME. Intervention and outcome Patient is treated with 10mEq/L/hr infusion of potassium chloride, methimazole and beta-blockers. He is stable and is in regular followup in medicine OPD. Relevance and impact Early diagnosis of HHPP is very essential to prevent fatal complications (cardiac and respiratory). It can be treated by timely potassium supplementation, methimazole and beta-blockers. Clinicians must be concerned about Hyperkalemia while supplementing Potassium in bed side. HHPP is a rare life-threatening complication of hyperthyroidism which is characterized by episodes of acute muscle weakness due to hypokalemia. Periodic paralysis (PP) is a muscle disease, characterized by episodes of painless muscle weakness. These episodes can be triggered by strenuous exercise, fasting, or consuming high-carbohydrate foods. Treatment cand be done by potassium supplementation until normalized serum potassium level. Patient must be kept in cardiac monitoring and serum potassium monitoring. Hyperthyroidism can be treated with methimazole. Patient must be kept under regular follow up in endocrinology department. Relapses can be prevented by treatment with radioactive iodine or surgery. Beta-blocking drugs have also been proven to reduce the frequency and severity of episodes.
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Affiliation(s)
| | | | - Prabhat Kiran Neupane
- Internship at Department of Medicine, Kist Medical College, Kathmandu, Nepal
- Corresponding author.
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Li J, Moten S, Rauf AA. The role of nephrologists in management of hypokalemic periodic paralysis: a case report. J Med Case Rep 2022; 16:65. [PMID: 35144692 PMCID: PMC8832865 DOI: 10.1186/s13256-022-03283-0] [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: 09/24/2021] [Accepted: 01/20/2022] [Indexed: 11/14/2022] Open
Abstract
Background Hypokalemic periodic paralysis is a chronic condition characterized by sporadic attacks of weakness associated with acute hypokalemia. Attacks are typically associated with specific triggers, such as prolonged rest following exercise or consumption of a high-carbohydrate meal. Most commonly, this condition is caused by an autosomal dominant calcium channel mutation, and patients typically have an established family medical history of hypokalemic periodic paralysis. Long-term complications include the development of progressive proximal myopathy. Oral potassium chloride may be considered for the treatment of an acute attack, with administration of acetazolamide or dichlorphenamide as long-term prophylaxis. Nephrologists can play an important role in the recognition and treatment of previously undiagnosed hypokalemic periodic paralysis. Case presentation We summarize the case of a 19-year-old white man who presented to the emergency department with undiagnosed attacks of hypokalemic periodic paralysis, and who reported, at follow-up, improvement in the severity and frequency of attacks with dichlorphenamide. Conclusions This case demonstrates the crucial role nephrologists can play, not only in the diagnosis of hypokalemic periodic paralysis, but also in the ongoing management of this condition. Patients should be advised to regularly follow up with their nephrology team for evaluation due to the risk of developing myopathy.
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Affiliation(s)
- Julia Li
- Midwestern University, Chicago College of Osteopathic Medicine, Downers Grove, IL, 60515, USA.
| | - Suha Moten
- Midwestern University, MABS, Downers Grove, IL, USA
| | - Anis A Rauf
- Nephrology Associates of Northern Illinois and Indiana, Hinsdale, IL, USA
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Luís T, Linhares MI, Silva SR, Rodrigues F. Novel CACNA1S mutation in hypokalaemic periodic paralysis. BMJ Case Rep 2022; 15:e245952. [PMID: 35039355 PMCID: PMC8768461 DOI: 10.1136/bcr-2021-245952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/05/2021] [Indexed: 11/03/2022] Open
Abstract
A 15-year-old girl was admitted to emergency department with an acute flaccid tetraparesis with no other symptoms. A history of recurrent similar episodes with spontaneous recovery was reported and no family history was known. Laboratory tests revealed severe hypokalaemia and hypokaluria. Symptoms resolution occurred after potassium replacement. The diagnosis of hypokalaemic periodic paralysis (HPP) was confirmed by genetic testing, which revealed a not previously described mutation in CACNA1S gene (c.3715C>G p.Arg1239Gly). HPP is a rare neuromuscular disorder that causes episodic attacks of flaccid paralysis with concomitant hypokalaemia. Primary forms of the disease are skeletal muscle ion channelopathies. HPP occurs due to a problem in potassium distribution rather than a total body potassium deficiency. Therefore potassium replacement should be carefully performed because of the risk of rebound hyperkalaemia. Knowing this rare entity is important in order to avoid diagnostic delays and so that proper treatment can be initiated to reduce morbidity and mortality.
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Affiliation(s)
- Telma Luís
- Department of Pediatrics, Centro Hospitalar do Baixo Vouga EPE, Aveiro, Portugal
| | - Maria Inês Linhares
- Centro Hospitalar e Universitario de Coimbra EPE Hospital Pediatrico de Coimbra, Coimbra, Portugal
| | - Sónia Regina Silva
- Department of Pediatrics, Centro Hospitalar do Baixo Vouga EPE, Aveiro, Portugal
| | - Filipa Rodrigues
- Department of Pediatrics, Centro Hospitalar do Baixo Vouga EPE, Aveiro, Portugal
- Child Development Unit-Neuropediatrics, Department of Pediatrics, Centro Hospitalar do Baixo Vouga, Aveiro, Portugal
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Abbas F, Shafi O, Latief M, Hassan Z, Farooq S. Familial hypokalemic periodic paralysis: A case series and review. MEDICAL JOURNAL OF DR. D.Y. PATIL VIDYAPEETH 2022. [DOI: 10.4103/mjdrdypu.mjdrdypu_417_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Treatment and Management of Disorders of Neuromuscular Hyperexcitability and Periodic Paralysis. Neuromuscul Disord 2022. [DOI: 10.1016/b978-0-323-71317-7.00018-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Su TH, Lee NC, Wu CS, Peng SSF, Fan PC. Episodic weakness and axonal sensorimotor neuropathy caused by a mitochondrial MT-ATP6 mutation. J Formos Med Assoc 2021; 121:2345-2350. [PMID: 34953645 DOI: 10.1016/j.jfma.2021.12.003] [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: 08/30/2021] [Revised: 11/18/2021] [Accepted: 12/02/2021] [Indexed: 11/26/2022] Open
Abstract
Episodic weakness is typically associated with a group of disorders so called periodic paralyses. Their major causes are mutation of ion channels, and have rarely been linked to mitochondrial disorders. We report a 20-year-old man with episodic weakness and axonal sensorimotor neuropathy since the age of 10 years. Analysis of the next generation sequencing data of the entire mitochondrial genome extracted from the blood revealed a homoplasmic m.9185T > C variant in MT-ATP6. Acetazolamide may be responsive for episodic weakness, and supplements with l-carnitine with coenzyme-Q10 seem to be beneficial as well. To the best of our knowledge, this is the first report in Taiwan which reveals episodic weakness and sensorimotor polyneuropathy as a unique phenotype of MT-ATP6 mutations.
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Affiliation(s)
- Tzu-Hsuan Su
- Department of Pediatrics, National Taiwan University Hospital, Taipei, Taiwan
| | - Ni-Chung Lee
- Department of Pediatrics, National Taiwan University Hospital, Taipei, Taiwan; Department of Medical Genetics, National Taiwan University Hospital, Taipei, Taiwan
| | - Chao-Szu Wu
- Department of Medical Genetics, National Taiwan University Hospital, Taipei, Taiwan
| | | | - Pi-Chuan Fan
- Department of Pediatrics, National Taiwan University Hospital, Taipei, Taiwan.
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Wang Q, Zhao Z, Shen H, Bing Q, Li N, Hu J. The clinical and genetic heterogeneity analysis of five families with primary periodic paralysis. Channels (Austin) 2021; 15:20-30. [PMID: 33345742 PMCID: PMC7757828 DOI: 10.1080/19336950.2020.1857980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Revised: 11/26/2020] [Accepted: 11/26/2020] [Indexed: 11/23/2022] Open
Abstract
To explore the clinical and genetic characteristics of five families with primary periodic paralysis (PPP). We reviewed clinical manifestations, laboratory results, electrocardiogram, electromyography, muscle biopsy, and genetic analysis from five families with PPP. Five families with PPP included: hypokalemic periodic paralysis type 1 (HypoPP1, CACNA1S, 1/5), hypokalemic periodic paralysis type 2 (HypoPP2, SCN4A, 2/5), normokalemic periodic paralysis (NormoPP, SCN4A, 1/5), and Andersen-Tawil syndrome (ATS, KCNJ2, 1/5). The basic clinical manifestations of five families were consistent with PPP, presenting with paroxysmal muscle weakness, with or without abnormal serum potassium. ATS was accompanied by ventricular arrhythmias, and skeletal and craniofacial anomalies, developing with a permanent fixed myopathy later. The electromyography showed diffuse myopathic discharge, and muscle biopsy showed tubular aggregates. Genetic testing revealed five families with PPP carried CACNA1S (R1242S), SCN4A (R675Q, T704M), and KCNJ2 (R218Q) respectively. The novel heterozygous R1242S mutation in CACNA1S caused a conformational change in the protein structure, and the amino acid of this mutation site was highly conserved among different species. SCN4A mutations led to two phenotypes of HypoPP2 and NormoPP. PPPs are autosomal dominant disorders of ion channel dysfunction characterized by episodic flaccid muscle weakness secondary to abnormal sarcolemmal excitability. PPPs are caused by mutations in skeletal muscle calcium channel CaV1.1 gene (CACNA1S), sodium channel NaV1.4 gene (SCN4A), and potassium channels Kir2.1, Kir3.4 genes (KCNJ2, KCNJ5), including HypoPP1, HypoPP2, NormoPP, HyperPP, and ATS, which have significant clinical and genetic heterogeneity. Diagnosis is based on the characteristic clinical presentation then confirmed by genetic testing.
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Affiliation(s)
- Quanquan Wang
- Department of Neuromuscular Disease, The Third Hospital of Hebei Medical University, Shijiazhuang, Hebei, China
| | - Zhe Zhao
- Department of Neuromuscular Disease, The Third Hospital of Hebei Medical University, Shijiazhuang, Hebei, China
| | - Hongrui Shen
- Department of Neuromuscular Disease, The Third Hospital of Hebei Medical University, Shijiazhuang, Hebei, China
| | - Qi Bing
- Department of Neuromuscular Disease, The Third Hospital of Hebei Medical University, Shijiazhuang, Hebei, China
| | - Nan Li
- Department of Neuromuscular Disease, The Third Hospital of Hebei Medical University, Shijiazhuang, Hebei, China
| | - Jing Hu
- Department of Neuromuscular Disease, The Third Hospital of Hebei Medical University, Shijiazhuang, Hebei, China
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Autism-associated mutations in K V7 channels induce gating pore current. Proc Natl Acad Sci U S A 2021; 118:2112666118. [PMID: 34728568 PMCID: PMC8609342 DOI: 10.1073/pnas.2112666118] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/21/2021] [Indexed: 12/12/2022] Open
Abstract
Autism spectrum disorder (ASD) adversely impacts >1% of children in the United States, causing social interaction deficits, repetitive behaviors, and communication disorders. Genetic analysis of ASD has advanced dramatically through genome sequencing, which has identified >500 genes with mutations in ASD. Mutations that alter arginine gating charges in the voltage sensor of the voltage-gated potassium (KV) channel KV7 (KCNQ) are among those frequently associated with ASD. We hypothesized that these gating charge mutations would induce gating pore current (also termed ω-current) by causing an ionic leak through the mutant voltage sensor. Unexpectedly, we found that wild-type KV7 conducts outward gating pore current through its native voltage sensor at positive membrane potentials, owing to a glutamine in the third gating charge position. In bacterial and human KV7 channels, gating charge mutations at the R1 and R2 positions cause inward gating pore current through the resting voltage sensor at negative membrane potentials, whereas mutation at R4 causes outward gating pore current through the activated voltage sensor at positive potentials. Remarkably, expression of the KV7.3/R2C ASD-associated mutation in vivo in midbrain dopamine neurons of mice disrupts action potential generation and repetitive firing. Overall, our results reveal native and mutant gating pore current in KV7 channels and implicate altered control of action potential generation by gating pore current through mutant KV7 channels as a potential pathogenic mechanism in autism.
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Distal renal tubular acidosis and hypokalaemic periodic paralysis during pregnancy. J Nephrol 2021; 35:1725-1729. [PMID: 34748193 DOI: 10.1007/s40620-021-01184-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 10/20/2021] [Indexed: 10/19/2022]
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Mutations associated with hypokalemic periodic paralysis: from hotspot regions to complete analysis of CACNA1S and SCN4A genes. Neurogenetics 2021; 23:19-25. [PMID: 34608571 DOI: 10.1007/s10048-021-00673-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 09/26/2021] [Indexed: 01/10/2023]
Abstract
Familial periodic paralyses (PPs) are inherited disorders of skeletal muscle characterized by recurrent episodes of flaccid muscle weakness. PPs are classified as hypokalemic (HypoPP), normokalemic (NormoPP), or hyperkalemic (HyperPP) according to the potassium level during the paralytic attacks. HypoPP is an autosomal dominant disease caused by mutations in the CACNA1S gene, encoding for Cav1.1 channel (HypoPP-1), or SCN4A gene, encoding for Nav1.4 channel (HypoPP-2). In the present study, we included 60 patients with a clinical diagnosis of HypoPP. Fifty-one (85%) patients were tested using the direct sequencing (Sanger method) of all reported HypoPP mutations in CACNA1S and SCN4A genes; the remaining 9 (15%) patients were analyzed through a next-generation sequencing (NGS) panel, including the whole CACNA1S and SCN4A genes, plus other genes rarely associated to PPs. Fifty patients resulted mutated: 38 (76%) cases showed p.R528H and p.R1239G/H CACNA1S mutations and 12 (24%) displayed p.R669H, p.R672C/H, p.R1132G/Q, and p.R1135H SCN4A mutations. Forty-one mutated cases were identified among the 51 patients managed with Sanger sequencing, while all the 9 cases directly analyzed with the NGS panel showed mutations in the hotspot regions of SCN4A and CACNA1S. Ten out of the 51 patients unresolved through the Sanger sequencing were further analyzed with the NGS panel, without the detection of any mutation. Hence, our data suggest that in HypoPP patients, the extension of genetic analysis from the hotspot regions using the Sanger method to the NGS sequencing of the entire CACNA1S and SCN4A genes does not lead to the identification of new pathological mutations.
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Kim HR, Jeon JW, Lee EJ, Ham YR, Na KR, Lee KW, Park KH, Kim SY, Choi DE. Confirming Genetic Abnormalities of Hypokalemic Periodic Paralysis Using Next-Generation Sequencing: A Case Report and Literature Review. Electrolyte Blood Press 2021; 19:10-14. [PMID: 34290819 PMCID: PMC8267070 DOI: 10.5049/ebp.2021.19.1.10] [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: 03/23/2021] [Revised: 05/12/2021] [Accepted: 05/13/2021] [Indexed: 11/05/2022] Open
Abstract
Hypokalemic periodic paralysis (hypoPP) is a disorder characterized by episodic, short-lived, and hypo-reflexive skeletal muscle weakness. HypoPP is a rare disease caused by genetic mutations related to expression of sodium or calcium ion channels. Most mutations are associated with autosomal dominant inheritance, but some are found in patients with no relevant family history. A 28-year-old man who visited the emergency room for paralytic attack was assessed in this study. He exhibited motor weakness in four limbs. There was no previous medical history or family history. The initial electrocardiogram showed a flat T wave and QT prolongation. His blood test was delayed, and sudden hypotension and bradycardia were observed. The blood test showed severe hypokalemia. After correcting hypokalemia, his muscle paralysis recovered without any neurological deficits. The patient's thyroid function and long exercise test results were normal. However, because of the history of high carbohydrate diet and exercise, hypoPP was suspected. Hence, next-generation sequencing (NGS) was performed, and a mutation of Arg669His was noted in the SCN4A gene. Although hypoPP is a rare disease, it can be suspected in patients with hypokalemic paralysis, and iden tification of this condition is important for preventing further attacks and improving patient outcomes. Diagnosing hypoPP through targeted NGS is a cost-effective and useful method.
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Affiliation(s)
- Hae Ri Kim
- Department of Internal Medicine, Division of Nephrology, Chungnam National University Sejong Hospital, Sejong, Republic of Korea
| | - Jae Wan Jeon
- Department of Internal Medicine, Division of Nephrology, Chungnam National University Sejong Hospital, Sejong, Republic of Korea
| | - Eu Jin Lee
- Department of Internal Medicine, Division of Nephrology, Chungnam National University Hospital, Daejeon, Republic of Korea
| | - Young Rok Ham
- Department of Internal Medicine, Division of Nephrology, Chungnam National University Hospital, Daejeon, Republic of Korea
| | - Ki Ryang Na
- Department of Internal Medicine, Division of Nephrology, Chungnam National University Hospital, Daejeon, Republic of Korea
| | - Kang Wook Lee
- Department of Internal Medicine, Division of Nephrology, Chungnam National University Hospital, Daejeon, Republic of Korea
| | - Kee Hong Park
- Department of Neurology, Seoul Medical Center, Seoul, Republic of Korea
| | - Seon Young Kim
- Department of Laboratory Medicine, Chungnam National University Hospital, Daejeon, Republic of Korea
| | - Dae Eun Choi
- Department of Internal Medicine, Division of Nephrology, Chungnam National University Hospital, Daejeon, Republic of Korea
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Hypokalemic Periodic Paralysis Precipitated by Thyrotoxicosis and Renal Tubular Acidosis. Case Rep Endocrinol 2021; 2021:4529009. [PMID: 34239739 PMCID: PMC8238611 DOI: 10.1155/2021/4529009] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 05/22/2021] [Accepted: 06/14/2021] [Indexed: 12/11/2022] Open
Abstract
Background Hypokalemic periodic paralysis is a rare neuromuscular disorder characterized by transient episodes of flaccid paralysis due to a defect in muscle ion channels. Most cases are hereditary, but it can be acquired. We present a case of acquired hypokalemic periodic paralysis associated with hyperthyroidism and renal tubular acidosis. Clinical Case. A 38-year-old female with a history of Graves' disease presented to the emergency department with generalized weakness and associated nausea, vomiting, and weight loss. Examination was significant for diffuse weakness in all extremities. Labs showed hypokalemia, hyperthyroidism, and nonanion gap metabolic acidosis with a positive urine anion gap. She was treated for hypokalemic periodic paralysis and renal tubular acidosis. Potassium replacement, propranolol, methimazole, and sodium bicarbonate were initiated. Her potassium gradually corrected with resolution of her symptoms. Further investigation revealed a history of dry eyes, dry mouth, and recurrent dental carries. She had positive ANA, SS-A, and SS-B antibodies. She was diagnosed with Sjögren's syndrome, which may have been associated with her Graves' disease and thus contributed to both her RTA and hyperthyroidism. Conclusion Early recognition and treatment of thyrotoxic periodic paralysis are important to prevent cardiac complications. Management includes potassium replacement with careful monitoring to prevent rebound hyperkalemia. The definitive treatment is to achieve euthyroid status.
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Danti FR, Invernizzi F, Moroni I, Garavaglia B, Nardocci N, Zorzi G. Pediatric Paroxysmal Exercise-Induced Neurological Symptoms: Clinical Spectrum and Diagnostic Algorithm. Front Neurol 2021; 12:658178. [PMID: 34140924 PMCID: PMC8203909 DOI: 10.3389/fneur.2021.658178] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 04/21/2021] [Indexed: 12/18/2022] Open
Abstract
Paroxysmal exercise-induced neurological symptoms (PENS) encompass a wide spectrum of clinical phenomena commonly presenting during childhood and characteristically elicited by physical exercise. Interestingly, few shared pathogenetic mechanisms have been identified beyond the well-known entity of paroxysmal exercise-induced dyskinesia, PENS could be part of more complex phenotypes including neuromuscular, neurodegenerative, and neurometabolic disease, epilepsies, and psychogenetic disorders. The wide and partially overlapping phenotypes and the genetic heterogeneity make the differential diagnosis frequently difficult and delayed; however, since some of these disorders may be treatable, a prompt diagnosis is mandatory. Therefore, an accurate characterization of these symptoms is pivotal for orienting more targeted biochemical, radiological, neurophysiological, and genetic investigations and finally treatment. In this article, we review the clinical, genetic, pathophysiologic, and therapeutic landscape of paroxysmal exercise induced neurological symptoms, focusing on phenomenology and differential diagnosis.
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Affiliation(s)
- Federica Rachele Danti
- Unit of Child Neurology, Department of Pediatric Neuroscience, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Istituto Neurologico Carlo Besta, Milan, Italy
| | - Federica Invernizzi
- Unit of Medical Genetics and Neurogenetics, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Istituto Neurologico C. Besta, Milan, Italy
| | - Isabella Moroni
- Unit of Child Neurology, Department of Pediatric Neuroscience, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Istituto Neurologico Carlo Besta, Milan, Italy
| | - Barbara Garavaglia
- Unit of Medical Genetics and Neurogenetics, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Istituto Neurologico C. Besta, Milan, Italy
| | - Nardo Nardocci
- Unit of Child Neurology, Department of Pediatric Neuroscience, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Istituto Neurologico Carlo Besta, Milan, Italy
| | - Giovanna Zorzi
- Unit of Child Neurology, Department of Pediatric Neuroscience, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Istituto Neurologico Carlo Besta, Milan, Italy
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Mantegazza M, Cestèle S, Catterall WA. Sodium channelopathies of skeletal muscle and brain. Physiol Rev 2021; 101:1633-1689. [PMID: 33769100 DOI: 10.1152/physrev.00025.2020] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Voltage-gated sodium channels initiate action potentials in nerve, skeletal muscle, and other electrically excitable cells. Mutations in them cause a wide range of diseases. These channelopathy mutations affect every aspect of sodium channel function, including voltage sensing, voltage-dependent activation, ion conductance, fast and slow inactivation, and both biosynthesis and assembly. Mutations that cause different forms of periodic paralysis in skeletal muscle were discovered first and have provided a template for understanding structure, function, and pathophysiology at the molecular level. More recent work has revealed multiple sodium channelopathies in the brain. Here we review the well-characterized genetics and pathophysiology of the periodic paralyses of skeletal muscle and then use this information as a foundation for advancing our understanding of mutations in the structurally homologous α-subunits of brain sodium channels that cause epilepsy, migraine, autism, and related comorbidities. We include studies based on molecular and structural biology, cell biology and physiology, pharmacology, and mouse genetics. Our review reveals unexpected connections among these different types of sodium channelopathies.
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Affiliation(s)
- Massimo Mantegazza
- Université Cote d'Azur, Valbonne-Sophia Antipolis, France.,CNRS UMR7275, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne-Sophia Antipolis, France.,INSERM, Valbonne-Sophia Antipolis, France
| | - Sandrine Cestèle
- Université Cote d'Azur, Valbonne-Sophia Antipolis, France.,CNRS UMR7275, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne-Sophia Antipolis, France
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Sampaio F, Soares S, Pereira S, Lemos JA, Mota Á. Sodium Channel Myotonia and a Novel Gly701Asp Mutation in the SCN4A Gene: From an Ophthalmological Symptom to a Familial Disease. Neuroophthalmology 2021; 45:41-44. [PMID: 33762787 DOI: 10.1080/01658107.2020.1779316] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
A six-month-old female child came to an ophthalmology consultation because of a convergent strabismus, myotonia of the orbicularis muscles and difficulty walking in cold environments. Further investigation identified a family history of muscular myotonia in the father, grandmother and uncle. The father also presented with ocular myotonia. The child and family members underwent genetic testing, which was negative for CLCN1 mutations but was positive for a novel heterozygotic Gly701Asp mutation in the SCN4A gene, compatible with sodium channel myotonia. The non-dystrophic myotonias are caused by dysfunction of key skeletal muscle ion channels. Before the advent of DNA sequencing, non-dystrophic myotonias were differentiated based on clinical phenotypes. Sodium channel myotonia disorders are classically of dominant inheritance, in which eye closure myotonia is the most frequent manifestation. Over 40 different mutations have been reported in the SCN4A gene. The Gly701Asp mutation in exon 13 identified in this family has not been described before.
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Affiliation(s)
- Filipa Sampaio
- Ophthalmology Department, Hospital Pedro Hispano, Unidade Local De Saúde De Matosinhos, Matosinhos, Portugal
| | - Sérgia Soares
- Pediatric Department, Hospital Pedro Hispano, Unidade Local De Saúde De Matosinhos, Matosinhos, Portugal
| | - Sara Pereira
- Ophthalmology Department, Hospital Pedro Hispano, Unidade Local De Saúde De Matosinhos, Matosinhos, Portugal
| | - José Alberto Lemos
- Ophthalmology Department, Hospital Pedro Hispano, Unidade Local De Saúde De Matosinhos, Matosinhos, Portugal
| | - Ágata Mota
- Ophthalmology Department, Hospital Pedro Hispano, Unidade Local De Saúde De Matosinhos, Matosinhos, Portugal
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Jiang D, Gamal El-Din T, Zheng N, Catterall WA. Expression and purification of the cardiac sodium channel Na V1.5 for cryo-EM structure determination. Methods Enzymol 2021; 653:89-101. [PMID: 34099183 DOI: 10.1016/bs.mie.2021.01.030] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Voltage-gated sodium channel NaV1.5 is responsible for initiating and propagating cardiac action potentials by selectively conducting Na+ into cardiomyocytes. Class-I antiarrhythmic drugs target NaV1.5 for treatment of arrhythmias. During the last few years, cryogenic electron microscopy (cryo-EM) has become a powerful technique to determine the structures of ion channels at atomic level. In order to reveal the structural features of NaV1.5 and the structural basis for its interaction with antiarrhythmic drugs by cryo-EM, NaV1.5 protein must be expressed at high levels and purified to homogeneity. In this chapter, we discuss the expression and purification of NaV1.5 in a mammalian expression system. We optimized the construct by deleting unstructured intracellular loops of rat NaV1.5 while retaining core functional regions. The resulting rNaV1.5C is fully functional and is blocked by Class-I antiarrhythmic drugs in a state-dependent manner. Protocols are presented for expressing and purifying sufficient sample of NaV1.5 for preparing cryo-EM grids. The resulting cryo-EM structure is briefly described.
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Affiliation(s)
- Daohua Jiang
- Department of Pharmacology, University of Washington, Seattle, WA, United States; Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
| | - Tamer Gamal El-Din
- Department of Pharmacology, University of Washington, Seattle, WA, United States
| | - Ning Zheng
- Department of Pharmacology, University of Washington, Seattle, WA, United States; Howard Hughes Medical Institute, University of Washington, Seattle, WA, United States
| | - William A Catterall
- Department of Pharmacology, University of Washington, Seattle, WA, United States.
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Hiraide T, Fukumura S, Yamamoto A, Nakashima M, Saitsu H. Familial periodic paralysis associated with a rare KCNJ5 variant that supposed to have incomplete penetrance. Brain Dev 2021; 43:470-474. [PMID: 33199157 DOI: 10.1016/j.braindev.2020.10.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 10/13/2020] [Accepted: 10/22/2020] [Indexed: 10/23/2022]
Abstract
BACKGROUND The periodic paralyses are a group of skeletal muscle channelopathies caused by variants in several ion channel genes. Potassium Inwardly Rectifying Channel Subfamily J Member 5 (KCNJ5) encodes the G-protein-activated inwardly rectifying potassium channel 4 (Kir3.4) and the heterozygous KCNJ5 variants cause familial hyperaldosteronism and long QT syndrome (LQTS). Recent studies suggested that variants in KCNJ5 are also causative for Andersen-Tawil syndrome, which showed periodic paralysis and characteristic electrocardiogram features. CLINICAL REPORT We found a heterozygous KCNJ5 variant c.1159G > C, p.(Gly387Arg) in an individual with familial periodic paralysis using exome sequencing. Sanger sequencing revealed that this variant was inherited from his affected mother. The same variant had been previously found in two cases of familial LQTS or Andersen-Tawil syndrome, and functional analysis suggested that this variant might have loss of function effect on channel activity. However, the allele frequency of c.1159G > C variant in an East Asian population of public databases ranged from 0.21% to 0.25%, indicating possible incomplete penetrance. CONCLUSIONS Our two patients expand the phenotypic spectrum associated with the c.1159G > C KCNJ5 variant, though the variant has very low penetrance.
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Affiliation(s)
- Takuya Hiraide
- Department of Biochemistry, Hamamatsu University School of Medicine, Japan
| | - Shinobu Fukumura
- Department of Pediatrics, Sapporo Medical University School of Medicine, Japan
| | - Akiyo Yamamoto
- Department of Pediatrics, Sapporo Medical University School of Medicine, Japan
| | - Mitsuko Nakashima
- Department of Biochemistry, Hamamatsu University School of Medicine, Japan.
| | - Hirotomo Saitsu
- Department of Biochemistry, Hamamatsu University School of Medicine, Japan
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Bhasin D, Kumar R, Gupta A. A Young Man With Generalized Muscle Weakness and a Peculiar Electrocardiogram: Carpe Diem. JAMA Intern Med 2021; 181:374-376. [PMID: 33315059 DOI: 10.1001/jamainternmed.2020.7119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Dinkar Bhasin
- Department of Cardiology, Vardhman Mahavir Medical College and Safdarjung Hospital, New Delhi, India
| | - Rahul Kumar
- Department of Cardiology, Vardhman Mahavir Medical College and Safdarjung Hospital, New Delhi, India
| | - Anunay Gupta
- Department of Cardiology, Vardhman Mahavir Medical College and Safdarjung Hospital, New Delhi, India
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Abstract
This chapter describes what a channelopathy is and how mutations in the genes result in different types of clinical abnormalities. It provides a description of common types of cardiac channelopathies with examples of how there are some areas of overlap with sensory-neuromuscular channelopathies. We describe the cardiac channelopathies of Jervell and Lange-Nielson syndrome, Andersen-Tawil syndrome, Timothy syndrome, catecholaminergic polymorphic ventricular tachycardia, Brugada syndrome, and sinoatrial node dysfunction and deafness. We also discuss sudden unexpected death in epilepsy and how it could relate to some cardiac channelopathies.
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Parihar J, Vishnu VY, Singh MB, Goyal V, Padma Srivastava MV. Clinodactyly - A Clinical Clue to Diagnose a Hereditary Periodic Paralysis. Ann Indian Acad Neurol 2021; 23:738-739. [PMID: 33623294 PMCID: PMC7887508 DOI: 10.4103/aian.aian_400_20] [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: 05/08/2020] [Revised: 05/10/2020] [Accepted: 05/15/2020] [Indexed: 11/21/2022] Open
Affiliation(s)
- Jasmine Parihar
- Department of Neurology, All India Institute of Medical Sciences, Lady Hardinge Medical College (current affailiation), New Delhi, India
| | - Venugopalan Y Vishnu
- Department of Neurology, All India Institute of Medical Sciences, New Delhi, India
| | - Mamta B Singh
- Department of Neurology, All India Institute of Medical Sciences, New Delhi, India
| | - Vinay Goyal
- Department of Neurology, All India Institute of Medical Sciences, New Delhi, India
| | - M V Padma Srivastava
- Department of Neurology, All India Institute of Medical Sciences, New Delhi, India
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Sharawat IK, Suthar R, Sankhyan N, Singhi P. Primary Hypokalemic Periodic Paralysis: Long-term Management and Complications in a Child. J Pediatr Neurosci 2020; 15:132-134. [PMID: 33042247 PMCID: PMC7519733 DOI: 10.4103/jpn.jpn_101_19] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2019] [Revised: 09/04/2019] [Accepted: 03/27/2020] [Indexed: 11/16/2022] Open
Abstract
Hypokalemic periodic paralysis (HPP) is a rare genetically determined neuromuscular disorder caused by mutation in skeletal muscles calcium and sodium channels. It presents with recurrent episodes of flaccid paralysis. A 9-year-old girl presented with recurrent episodic flaccid quadriparesis with complete recovery in-between the episodes. Investigations during the acute episode revealed marked hypokalemia with electrocardiogram changes. Next-generation sequencing showed pathogenic missense mutation in CACNA1S gene. She responded well to oral potassium supplementation, acetazolamide, and spironolactone therapy. Muscle weakness in HPP is reversible, and long-term management reduces frequency of paralysis and prevents permanent weakness.
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Affiliation(s)
- Indar K Sharawat
- Pediatric Neurology Division, Department of Pediatrics, All India Institute of Medical Sciences, Rishikesh, India
| | - Renu Suthar
- Pediatric Neurology Unit, Department of Pediatrics, Post Graduate Institute of Medical Education and Research, Chandigarh, India
| | - Naveen Sankhyan
- Pediatric Neurology Unit, Department of Pediatrics, Post Graduate Institute of Medical Education and Research, Chandigarh, India
| | - Pratibha Singhi
- Pediatric Neurology Unit, Department of Pediatrics, Post Graduate Institute of Medical Education and Research, Chandigarh, India.,Pediatric Neurology and Neurodevelopment, Department of Pediatrics, Medanta, The medicity, Gurugram, Haryana, India
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Abstract
PURPOSE OF REVIEW This article aims to review the current and upcoming treatment options of primary muscle channelopathies including the non-dystrophic myotonias and periodic paralyses. RECENT FINDINGS The efficacy of mexiletine in the treatment of myotonia is now supported by two randomised placebo-controlled trials, one of which utilised a novel aggregated n-of-1 design. This has resulted in licencing of the drug via orphan drug status. There is also good evidence that mexiletine is well tolerated and safe in this patient group without the need for intensive monitoring. A range of alternative antimyotonic treatment options include lamotrigine, carbamazepine and ranolazine exist with variable evidence base. In vitro studies have shown insight into reasons for treatment failure of some medications with certain genotypes opening the era of mutation-specific therapy such as use of flecainide. In the periodic paralyses, the ability of MRI to distinguish between reversible oedema and irreversible fatty replacement makes it an increasingly useful tool to guide and assess pharmacological treatment. Unfortunately, the striking efficacy of bumetanide in hypokalaemic periodic paralysis animal models was not replicated in a recent pilot study in humans. SUMMARY The treatment of skeletal muscle channelopathies combines dietary and lifestyle advice together with pharmacological interventions. The rarity of these conditions remains a barrier for clinical studies but the example of the aggregated n-of-1 trial of mexiletine shows that innovative trial design can overcome these hurdles. Further research is required to test efficacy of drugs shown to have promising characteristics in preclinical experiments such as safinamide, riluzule and magnesium for myotonia or bumetanide for hypokalaemic periodic paralysis.
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Affiliation(s)
- Nantaporn Jitpimolmard
- Queen Square Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, UCL, London, UK
- Rehabilitation Medicine Department, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Emma Matthews
- Queen Square Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, UCL, London, UK
- Atkinson-Morley Neuromuscular Centre, St George’s University Hospitals Foundation Trust, London, UK
| | - Doreen Fialho
- Queen Square Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, UCL, London, UK
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