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Reis MC, Mandler L, Kang J, Oliver D, Halaszovich C, Nolte D. A novel KCND3 variant in the N-terminus impairs the ionic current of Kv4.3 and is associated with SCA19/22. J Cell Mol Med 2024; 28:e70039. [PMID: 39180521 PMCID: PMC11344468 DOI: 10.1111/jcmm.70039] [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: 05/24/2024] [Accepted: 07/05/2024] [Indexed: 08/26/2024] Open
Abstract
Spinocerebellar ataxias (SCAs) are a genetically heterogeneous group of autosomal dominant movement disorders. Among the SCAs associated with impaired ion channel function, SCA19/22 is caused by pathogenic variants in KCND3, which encodes the voltage-gated potassium channel Kv4.3. SCA19/22 is clinically characterized by ataxia, dysarthria and oculomotor dysfunction in combination with other signs and symptoms, including mild cognitive impairment, peripheral neuropathy and pyramidal signs. The known KCND3 pathogenic variants are localized either in the transmembrane segments, the connecting loops, or the C-terminal region of Kv4.3. We have identified a novel pathogenic variant, c.455A>G (p.D152G), localized in the N-terminus of Kv4.3. It is located in the immediate neighbourhood of the T1 domain, which is responsible for multimerization with the β-subunit KChIP2b and thus for the formation of functional heterooctamers. Electrophysiological studies showed that p.D152G does not affect channel gating, but reduces the ionic current in Kv4.3, even though the variant is not located in the transmembrane domains. Impaired channel trafficking to the plasma membrane may contribute to this effect. In a patient with a clinical picture corresponding to SCA19/22, p.D152G is the first pathogenic variant in the N-terminus of Kv4.3 to be described to date with an effect on ion channel activity.
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Affiliation(s)
| | - Laura Mandler
- Institute of Human GeneticsJustus‐Liebig‐University GiessenGiessenGermany
- Present address:
Department of NeurologyJustus‐Liebig‐University GiessenGiessenGermany
| | - Jun‐Suk Kang
- Department of NeurologyGoethe‐University FrankfurtFrankfurtGermany
- Present address:
NeuropraxisFrankfurtGermany
| | - Dominik Oliver
- Institute of PhysiologyPhilipps‐University MarburgMarburgGermany
| | | | - Dagmar Nolte
- Institute of Human GeneticsJustus‐Liebig‐University GiessenGiessenGermany
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Ahammed MR, Ananya FN. Association of Cardiac Electrical Disorders With KCND3 Gene Mutation. Cureus 2023; 15:e34597. [PMID: 36883079 PMCID: PMC9985904 DOI: 10.7759/cureus.34597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/03/2023] [Indexed: 02/05/2023] Open
Abstract
Globally, cardiac channelopathies leading to electrical disorders are responsible for a significant number of sudden cardiac deaths without structural heart disease. Many genes encoding different ion channels in the heart were identified and their impairment was found to be associated with life-threatening cardiac abnormalities. KCND3, one of the genes expressed both in the heart and brain, is reported to have an association with Brugada syndrome, early-onset atrial fibrillation, early repolarization syndrome, and sudden unexplained death syndrome. KCND3 genetic screening could be a promising tool for functional studies for an understanding of the pathogenesis and genetic determinants of the above-mentioned electrical disorders.
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Affiliation(s)
- Md Ripon Ahammed
- Internal Medicine, Icahn School of Medicine at Mount Sinai, Queens Hospital Center, New York, USA
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Li M, Liu F, Hao X, Fan Y, Li J, Hu Z, Shi J, Fan L, Zhang S, Ma D, Guo M, Xu Y, Shi C. Rare KCND3 Loss-of-Function Mutation Associated With the SCA19/22. Front Mol Neurosci 2022; 15:919199. [PMID: 35813061 PMCID: PMC9261871 DOI: 10.3389/fnmol.2022.919199] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 05/19/2022] [Indexed: 12/15/2022] Open
Abstract
Spinocerebellar ataxia 19/22 (SCA19/22) is a rare neurodegenerative disorder caused by mutations of the KCND3 gene, which encodes the Kv4. 3 protein. Currently, only 22 KCND3 single-nucleotide mutation sites of SCA19/22 have been reported worldwide, and detailed pathogenesis remains unclear. In this study, Sanger sequencing was used to screen 115 probands of cerebellar ataxia families in 67 patients with sporadic cerebellar ataxia and 200 healthy people to identify KCND3 mutations. Mutant gene products showed pathogenicity damage, and the polarity was changed. Next, we established induced pluripotent stem cells (iPSCs) derived from SCA19/22 patients. Using a transcriptome sequencing technique, we found that protein processing in the endoplasmic reticulum was significantly enriched in SCA19/22-iPS-derived neurons and was closely related to endoplasmic reticulum stress (ERS) and apoptosis. In addition, Western blotting of the SCA19/22-iPS-derived neurons showed a reduction in Kv4.3; but, activation of transcription factor 4 (ATF4) and C/EBP homologous protein was increased. Therefore, the c.1130 C>T (p.T377M) mutation of the KCND3 gene may mediate misfold and aggregation of Kv4.3, which activates the ERS and further induces neuron apoptosis involved in SCA19/22.
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Affiliation(s)
- Mengjie Li
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
| | - Fen Liu
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
- Academy of Medical Sciences of Zhengzhou University, Zhengzhou, China
| | - Xiaoyan Hao
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
- Academy of Medical Sciences of Zhengzhou University, Zhengzhou, China
| | - Yu Fan
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
- Academy of Medical Sciences of Zhengzhou University, Zhengzhou, China
| | - Jiadi Li
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
- Academy of Medical Sciences of Zhengzhou University, Zhengzhou, China
| | - Zhengwei Hu
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
- Academy of Medical Sciences of Zhengzhou University, Zhengzhou, China
| | - Jingjing Shi
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
- Department of Cell Biology and Medical Genetics, Basic Medical College of Zhengzhou University, Zhengzhou, China
| | - Liyuan Fan
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
- Academy of Medical Sciences of Zhengzhou University, Zhengzhou, China
| | - Shuo Zhang
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
- Academy of Medical Sciences of Zhengzhou University, Zhengzhou, China
| | - Dongrui Ma
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
| | - Mengnan Guo
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
| | - Yuming Xu
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
- Department of Cell Biology and Medical Genetics, Basic Medical College of Zhengzhou University, Zhengzhou, China
- Henan Key Laboratory of Cerebrovascular Diseases, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
- Institute of Neuroscience, Zhengzhou University, Zhengzhou, China
- The Henan Medical Key Laboratory of Hereditary Neurodegenerative Diseases, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
- The Key Laboratory of Cerebrovascular Diseases Prevention and Treatment, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
| | - Changhe Shi
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
- Henan Key Laboratory of Cerebrovascular Diseases, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
- Institute of Neuroscience, Zhengzhou University, Zhengzhou, China
- The Henan Medical Key Laboratory of Hereditary Neurodegenerative Diseases, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
- The Key Laboratory of Cerebrovascular Diseases Prevention and Treatment, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
- *Correspondence: Changhe Shi
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