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PubMed2026

Genetic Research on Cardiac Channelopathies in African and African-Descent Populations: A Scoping Review.

Cardiac channelopathies are inherited arrhythmias that can lead to sudden cardiac death. Despite Africa's extensive genomic diversity, African and African-descent populations remain underrepresented in genetic research, creating gaps in variant interpretation and clinical care. This scoping review aims to map the extent, range, and nature of genetic research on cardiac channelopathies in these populations and to identify key geographic, thematic, and methodological gaps. Using the Joanna Briggs Institute scoping review methodology and the Population-Concept-Context framework, systematic searches in PubMed, Embase, and Web of Science identified original human studies on cardiac channelopathies with genetic data. Extracted variables included study characteristics, populations, types of channelopathies, and reported genes and variants. Forty-four studies met the inclusion criteria. Most studies originated from the United States and South Africa, while West, Central, and East Africa were largely underrepresented. US Black individuals and South African individuals of continental African or African-descended ancestry (excluding populations of European descent such as Cape Afrikaner people) were the most studied groups, with other continental African groups rarely included. Long QT syndrome was the predominant focus, and SCN5A, KCNQ1, and KCNH2 were the most frequently analyzed genes. Many of the genetic variants discussed remained of uncertain significance due to limited functional validation and the underrepresentation of African genomes in reference databases. Genetic research on cardiac channelopathies in populations of African ancestry is limited, restricting variant interpretation, counseling, and risk prediction. Broader African inclusion, expanded gene screening, and functional studies are essential to improve diagnostics and promote equity in genomic medicine.

Humans↗

PubMed2026

Protein sorting and proteostasis mechanisms in CFTR-related exocrine pancreas dysfunction: A systematic narrative review.

The pancreas consists of exocrine and endocrine compartments. In the exocrine pancreas, cystic fibrosis transmembrane conductance regulator (CFTR) functions mainly in ductal epithelial cells as a chloride and bicarbonate channel. Its activity depends on proper protein folding, trafficking, and localization to the apical membrane. This systematic narrative review aims to synthesize the available evidence on the role of protein sorting machinery in CFTR channelopathies and its contribution to exocrine pancreatic dysfunction. A thorough search was conducted using PRISMA criteria on PubMed, Wiley Online Library, and Scopus for studies published in English between January 2000 and November 2025. Twenty studies that met the inclusion criteria were included in this review. Pathogenic CFTR variants impair protein folding, endoplasmic reticulum (ER) exit, and endosomal recycling, resulting in reduced apical membrane expression and stability. These defects disrupt the localization of associated transporters and secretory proteins, impair ductal bicarbonate secretion, alter zymogen handling, and promote acinar injury, although these claims are supported mainly by indirect experimental models and therefore require clinical confirmation. CFTR channelopathies in the exocrine pancreas encompass both ion transport defects and broader disruptions of protein sorting machinery. CFTR may contribute to the assembly, stabilization, or localization of selected apical transport complexes, and its loss can secondarily alter epithelial organization. Therapeutic approaches targeting both channel correction and intracellular trafficking may improve pancreatic function and mitigate disease progression.

Humans↗

PubMed2026

Real-world clinical utility of exome sequencing in pediatric drug-resistant epilepsy: Experience from a tertiary center in Thailand.

BACKGROUND: Genomic testing has increasingly contributed to the diagnosis and management of pediatric drug-resistant epilepsy (DRE), particularly in patients with suspected genetic etiologies. This study evaluated the diagnostic yield and real- world clinical utility of whole-exome sequencing (WES) in children with DRE. METHODS: Children with DRE and seizure onset before 15 years of age were enrolled between January 2020 and December 2023. Clinical data, including demographics, seizure characteristics, developmental history, electroencephalography (EEG), brain magnetic resonance imaging (MRI), and prior investigations, were reviewed. WES was performed in all probands and, when available, their parents. Variants were interpreted according to standard guidelines. Clinical utility and 1-year seizure and developmental outcomes were assessed from follow-up records. RESULTS: Fifty-six patients (23 males, 33 females) were included. The median age at seizure onset was 1 year (interquartile range [IQR] 0.3-4 years), and 96.4% had developmental comorbidities. Pathogenic or likely pathogenic variants were identified in 39% (22/56), with the highest diagnostic yield in children with seizure onset before 3 years of age. Channelopathies accounted for most genetically solved cases (68%), predominantly involving sodium channel genes. Genetic diagnoses provided clinical utility in 73% (16/22) of solved cases by guiding treatment and precision management. At 1-year follow-up, genetically solved patients showed more favorable seizure and developmental outcomes than those with genetically unsolved patients. CONCLUSION: WES achieved a 39% diagnostic yield and substantial clinical utility in pediatric DRE, particularly in early-onset and channelopathy-related disorders. These findings support early molecular diagnosis to facilitate genotype-informed management in appropriately selected children. However, the more favorable developmental and seizure outcomes observed in genetically solved patients should be interpreted with caution, as they may have been influenced by multiple factors beyond genetic diagnosis. In resource-limited settings, careful clinical phenotyping remains essential for treatment decisions and for prioritizing children for genomic testing.

Clinical utility↗

PubMed2026

Utero-placental calcium and magnesium ion channels: A systematic review of obstetric implications of their alterations.

Despite the established roles of calcium (Ca2+) and magnesium (Mg2+) in placental function and uterine contractility, limited information exists on how dysregulation of major ion channels contributes to poor pregnancy outcomes. We synthesized data on the consequences of Ca2+ and Mg2+ channelopathies in uterine and placental functions. Using PubMed, Wiley Online, AJOL, and Web of Science databases for article search, a systematic review of forty-nine papers published between 2000 and March 2026 was carried out and reported in accordance with the PRISMA 2020 guideline. Based on the PICO framework, eligible studies involving human, animal, and in vitro designs were chosen and subjected to narrative analysis. L-type and T-type voltage-gated Ca2+ channels, together with transient receptor potential channels, emerged as principal mediators of placental Ca2+ transport and myometrial contractility. Mechanosensitive Piezo1 channels mediate stretch-activated Ca2+ influx, while store-operated Ca2+ entry pathways involving STIM1-Orai1 sustain intracellular Ca2+ homeostasis. Potassium-Ca2+ coupling channels modulated membrane hyperpolarization and anti-labor effects, and intracellular regulators such as PMCA and RYR1 fine-tuned Ca2+ homeostasis. The Mg2+ transporters are essential for preserving Mg2+ homeostasis and regulating Ca2+-dependent excitability. Dysregulation of these ion channel systems was consistently linked to abnormal uterine contractility, preterm birth, preeclampsia, fetal growth restriction, and adverse pregnancy outcomes. Both Ca2+ and Mg2+ ion channelopathies represent both a potential therapeutic target and a mechanistic factor underlying key obstetric complications.

Female↗

PubMed2026

Beyond ion channel dysfunction: Integration of the transcriptome and proteome from patient-specific re-engineered cardiac cells, and population-level QT genome-wide association study reveals broad cellular dysfunction.

BACKGROUND: Congenital long QT syndrome (LQTS) is a cardiac channelopathy with increased risk of cardiac-triggered syncope/seizures, sudden cardiac arrest, and sudden cardiac death. OBJECTIVE: This study aimed to describe the transcriptomic and proteomic profiles in patient-derived inducible pluripotent stem cell-derived cardiomyocyte (iPSC-CM) models of the 3 canonical genotypes of congenital LQTS: LQT1, LQT2, and LQT3 and integrate these omics-level findings with each other and with population/clinical level QT-genome-wide association study (GWAS) data. METHODS: LQT1, LQT2, LQT3 and respective isogenic control iPSC-CMs were cultured, and RNA and protein samples were collected. RNA sequencing and mass spectrometry-enabled proteomic analysis was performed. PrediXcan analysis was performed using QT GWAS summary statistics and transcriptome expression data. Differential gene and protein expression and ingenuity pathway analysis (IPA) was performed comparing each LQT genotype with its respective isogenic control. RESULTS: 1645 differentially expressed genes (DEGs) were identified; 13 were altered in all 3 LQTS genotypes. IPA analysis of DEGs revealed 301 altered pathways; 47 were altered in all LQTS genotypes. Proteomic analysis identified 2561 differentially expressed proteins (DEPs); 30 were altered in all 3 genotypes. IPA analysis of DEPs identified 646 altered pathways. 306 genes/proteins were identified as significantly altered in both the transcriptome and proteome; pathway analysis of these 301 genes identified 201 altered pathways. 7 pathways were altered in all 3 LQTS genotypes in both the transcriptome and proteome. Integration of the population-level PrediXcan results and the cardiomyocyte-derived omics results identified multiple shared pathways. CONCLUSION: Multi-omics analysis of LQTS and integration of omics results with QT GWAS data reveals that primary LQTS-causative ion channel defects precipitate secondary alterations in a wide range of cellular pathways. Our findings suggest more broad molecular level changes throughout the cell. This study lays the foundation for further exploration of broad cellular changes resulting from ion channel disturbances and how they contribute to disease mechanism.

Humans↗

PubMed2025

Spinocerebellar Ataxia 27 A with Episodic Ataxia: Case Series of Fibroblast Growth Factor 14 (FGF14) Microdeletions.

Spinocerebellar ataxia 27 A (SCA27A) is a form of progressive cerebellar ataxia due to pathogenic variants in the Fibroblast Growth Factor 14 (FGF14) gene. The objective of this paper is to characterise the clinical spectrum of SCA27A microdeletions (> 50 bp, <2Mbp), and report two novel cases. Literature searches of PubMed, OMIM and ClinVar were carried out. We identified SCA27A microdeletions in 32 cases across 11 families. The phenotypic presentation is: 75% (24/32) nystagmus, 46% (15/32) ataxia, 21% (7/32) episodic ataxia, 21% (7/32) tremor, 15% (5/32) dysarthria, 34% (11/32) learning disability, 28% (8/32) neuropsychiatric disease. The presentation is variable within and between families. Episodic symptoms, nystagmus, learning disability and neuropsychiatric symptoms occur at an earlier age. Patient 1 represents the first case with a 58 kb FGF14 deletion who presented with a paroxysmal movement disorder. Patient 2 carries a 545 kb deletion and developed episodic ataxia and trigeminal neuralgia, a novel feature not previously described in this cohort. We report two cases of heterozygous FGF14 microdeletions: Patient 1 (58 kb) and Patient 2 (545 kb), expanding the phenotypic spectrum of FGF14 structural variants to 32 cases across 11 families. We review potential mechanism from pre-clinical studies relating FGF14 haploinsufficiency to cerebellar, cognitive, neuropsychiatric symptoms, as well as trigeminal neuralgia. We propose the hypothesis that the episodic symptoms in SCA27A align with the molecular pathology of a channelopathy and propose management strategies based on this insight.

Humans↗

PubMed2025

The role of iPSC research for insight into inherited arrhythmia conditions.

Human induced pluripotent stem cells (iPSCs) have emerged as a transformative platform for modeling inherited cardiac arrhythmia syndromes and uncovering human-specific disease mechanisms. However, the promise of iPSC-derived cardiomyocytes lies beyond the recapitulation of arrhythmogenic phenotypes and channelopathies. In this review, we explore recent works which have enabled mechanistic interrogation and therapeutic insight for inherited arrhythmia syndromes, beyond the capabilities of traditional animal models. Such studies have leveraged iPSCs to elucidate the role of splice variants, transcriptional regulation, and mitochondrial stress in arrhythmogenesis. Further, iPSC systems have proven important for reclassifying variants of uncertain significance and in modeling idiopathic arrhythmias where genotype-phenotype links are elusive. Advances in directed differentiation now permit chamber-specific cardiac cell generation, allowing for atrial and ventricular disease modeling and revealing critical cell-cell interactions. iPSCs also serve as high-fidelity precursor platforms for drug testing, offering predictive insight into mutation-specific responses to pharmacologic and genetic therapies. Though limitations in maturation and scalability persist, ongoing efforts for integration with tissue engineering, multi-cellular models, and computational frameworks are evolving to improve model reliability. iPSC-based systems now occupy a critical role in arrhythmia research, bridging basic discovery with translational applications, thereby contributing to personalizing care and advancing therapeutics in inherited and idiopathic arrhythmic syndromes.

Humans↗

PubMed2026

Diagnosis and management of very rare primary arrhythmia syndromes in children and adults: a Clinical Consensus Statement of the European Heart Rhythm Association of the ESC and the Association of Cardiovascular Nursing & Allied Professions of the ESC, endorsed by the Association for European Paediatric and Congenital Cardiology.

Very rare and ultra-rare primary inherited arrhythmia syndromes (IAS) represent a heterogeneous group of disorders associated with a significant risk of sudden cardiac death, often manifesting from foetal life to early adulthood. Current guidelines primarily address more common IAS and provide limited, non-specific recommendations for these rare entities, particularly in paediatric populations. This European Heart Rhythm Association Clinical Consensus Statement, developed in collaboration with the Association of Cardiovascular Nursing and Allied Professions and endorsed by the Association for European Paediatric and Congenital Cardiology, integrates available evidence with expert opinion. Recommendations were formulated through structured discussion and voting, following ESC consensus methodology, with a focus on clinically actionable gene-disease associations. The document provides a comprehensive framework for the diagnosis and management of very rare IAS, including calmodulinopathies, Andersen-Tawil syndrome, Timothy syndrome, TRDN-related disease, calcium release deficiency syndrome, and other atypical channelopathies. It highlights age-specific clinical presentations, the importance of genetic testing, and tailored therapeutic strategies, including pharmacological treatments, left cardiac sympathetic denervation, and selective use of implantable cardioverter-defibrillators. Special attention is given to paediatric considerations, foetal diagnosis, and the role of multidisciplinary care. The document also addresses arrhythmic risk in metabolic and cardiomyopathic conditions, as well as the importance of molecular autopsy and family screening in sudden unexplained death. This consensus document fills a critical gap by providing expert-driven, pragmatic guidance for the management of very rare IAS across the lifespan. It underscores the need for specialized care, international collaboration, and prospective registries to improve evidence generation, risk stratification, and patient outcomes in this vulnerable population.

Humans↗

PubMed2016

The Revolution in Migraine Genetics: From Aching Channels Disorders to a Next-Generation Medicine.

Channelopathies are a heterogeneous group of neurological disorders resulting from dysfunction of ion channels located in cell membranes and organelles. The clinical scenario is broad and symptoms such as generalized epilepsy (with or without fever), migraine (with or without aura), episodic ataxia and periodic muscle paralysis are some of the best known consequences of gain- or loss-of-function mutations in ion channels. We review the main clinical effects of ion channel mutations associated with a significant impact on migraine headache. Given the increasing and evolving use of genetic analysis in migraine research-greater emphasis is now placed on genetic markers of dysfunctional biological systems-we also show how novel information in rare monogenic forms of migraine might help to clarify the disease mechanisms in the general population of migraineurs. Next-generation sequencing (NGS) and more accurate and precise phenotyping strategies are expected to further increase understanding of migraine pathophysiology and genetics.

astrocyte↗

PubMed2026

Selectivity Filter KCND3 Variant Causes Spinocerebellar Ataxia 19/22 and KV4.3 Functional Loss.

BACKGROUND: Spinocerebellar ataxia type 19/22 (SCA19/22) is a rare autosomal dominant neurodegenerative disorder caused by KCND3 variants encoding the KV4.3 potassium channel. While most pathogenic variants result in loss-of-function (LOF), no pathogenic variants were previously identified in the channel's selectivity filter, a critical domain for ion selectivity. OBJECTIVES: To elucidate the genetic cause and functional LOF mechanisms underlying severe early-onset cerebellar ataxia and neurodevelopmental impairment in monozygotic twins. METHODS: We evaluated twins presenting with early-onset cerebellar ataxia, developmental delay, and cognitive impairment. Whole-exome sequencing (WES) identified a KCND3 c.1103T>C (p.L368P) variant. Functional impacts were assessed through HEK293T cell protein expression, Xenopus oocyte electrophysiology, and structural homology modeling. RESULTS: WES identified a heterozygous de novo p.L368P variant in the "TLGYG" selectivity filter sequence. Modeling predicted a pore radius reduction, blocking potassium permeation. Biochemical analyses revealed markedly reduced protein expression and impaired trafficking. Electrophysiological recordings confirmed complete potassium current loss and a strong dominant-negative effect on wild-type KV4.3 currents. Clinically, the twins exhibited severe intellectual disability, developmental delay, and cerebellar atrophy with pontine flattening, without epilepsy. CONCLUSIONS: Identifying the first pathogenic variant in the KV4.3 selectivity filter highlights its critical role in channel proteostasis and ion conductance. The p.L368P variant produces a pronounced LOF phenotype and broadens the SCA19/22 clinical spectrum, indicating the filter's structural integrity is a key determinant of disease severity. © 2026 International Parkinson and Movement Disorder Society.

KCND3↗

PubMed2025

Clinical and electrophysiological characterization of a SCN5A gain-of-function mutation associated with CPVT-like arrhythmia.

The present study aimed to characterize the SCN5A variant I1333V, found in five families with a history of suspected catecholaminergic polymorphic ventricular tachycardia (CPVT). SCN5A encodes the pore-forming subunit of the cardiac voltage-gated sodium channel NaV1.5. Gain of SCN5A function causes long QT syndrome type 3 (LQT3), but its involvement in CPVT is disputed. Nineteen patients harboring the I1333V variant were identified across five families, commonly presenting with exercise-induced arrhythmia, including polymorphic premature ventricular contractions, ventricular bigeminy, couplets, and ventricular tachycardias. Prolonged QT interval was a less consistent finding, and structural myocardial changes were absent. Human NaV1.5/β1 complexes were expressed in Xenopus laevis oocytes, using RNA combinations to emulate homozygous wild-type, heterozygous and homozygous I1333V-mutant conditions. Cells were studied using the cut-open oocyte Vaseline gap voltage-clamp to evaluate effects of I1333V on NaV1.5 function. NaV1.5(I1333V) channels required less depolarization to activate, classifying this variant as gain-of-function. Fast inactivation was unaffected, and action-potential (AP) clamp showed no significant differences in late Na+ current. A computational model of human ventricular myocyte excitability predicted no effect of I1333V on AP duration; instead, it showed stronger Na+ influx during the AP upstroke, concurrent with elevated Ca2+ import via the sodium‑calcium exchanger. Finally, NaV1.5(I1333V) channels exhibited a diminished response to cAMP (emulating adrenergic stimulation), which also likely contributes to arrhythmogenesis. In conclusion, I1333V is a gain-of-function variant of SCN5A with a unique set of functional consequences. It is associated with cardiac arrhythmia disease characterized by overlapping CPVT-like and LQT3 features. Our findings support that SCN5A should be considered in genetic screening of suspected CPVT.

NAV1.5 Voltage-Gated Sodium Channel↗

PubMed2025

What Should a Clinical Cardiologist Know About Cardiogenetics?

Inherited cardiovascular diseases are becoming increasingly prominent in clinical practice, significantly impacting diagnosis, risk assessment, and family screening strategies. Progress in genetic testing has broadened access to cardiogenetic evaluations, while also presenting new challenges in interpreting variants and incorporating findings into clinical care. This narrative review explores 20 essential questions that clinical cardiologists may face when dealing with suspected or confirmed inherited cardiac conditions. Organized as a practical, question-driven guide, it outlines when to consider a genetic cause, how to choose and interpret genetic tests, and how to manage patients regardless of their genetic test results. The review emphasizes variant classification based on American College of Medical Genetics and Genomics criteria, the importance of clinical context in interpreting uncertain results, and the principles behind family cascade screening. Particular attention is given to the management of relatives who carry a genetic variant but show no symptoms, and to the current limitations of genetic testing technologies (eg, performance). Ethical considerations, including the appropriate timing of testing in children minors, are also discussed. By connecting genetic insights with clinical cardiology, this review aims to support practical, informed decision making and promote effective collaboration with cardiogenetic specialists.

Humans↗

PubMed2025

Calmodulin D133H Disrupts Cav1.2 and Kv7.1 Regulation to Prolong Cardiac Action Potentials in Long QT Syndrome.

Calmodulin (CaM) plays a central role in cardiac excitation-contraction coupling by regulating ion channels, including the L-type calcium (Ca2+) channel Cav1.2 and the voltage-gated potassium (K+) channel Kv7.1. Mutations in CaM are linked to severe arrhythmogenic disorders such as Long QT syndrome (LQTS), yet the molecular mechanisms remain incompletely understood. Here, we investigate the structural and functional consequences of the arrhythmia-associated CaM variant D133H. Biophysical analysis revealed that D133H destabilises Ca2+ binding at the C-terminal lobe of CaM, altering its Ca2+-dependent conformational changes. Electrophysiological recordings demonstrated that CaM D133H impairs Ca2+-dependent inactivation (CDI) of Cav1.2, prolonging Ca2+ influx, while also reducing activation of Kv7.1, thereby limiting repolarising K+ currents. Together, these dual defects converge to prolong action potential duration, providing a mechanistic basis for arrhythmogenesis in LQTS. Our findings establish that CaM D133H perturbs both Ca2+ and K+ channel regulation, highlighting a shared pathway by which calmodulinopathy mutations disrupt cardiac excitability.

Calmodulin↗