Ciliopathies in Complex Congenital Heart Disease: Molecular Genetics, Embryologic Mechanisms and Clinical Implications Maria Felicia Gagliardi, Emanuele Micaglio, Angelo Micheletti, Sara Benedetti, Andrea Giordano, et al. Genes, 2026 Background/Objectives: Congenital heart malformations (CHDs) are not rare diseases, and, in many cases, their pathogenic mechanisms are well established. Several conotruncal defects are associated with genetic syndromes such as DiGeorge syndrome and RASopathies, reflecting shared developmental pathways affecting cardiac outflow tract formation. However, even common CHDs may occur within complex syndromic contexts, making early diagnosis essential for optimal management. This review aims to provide a unifying framework linking ciliary dysfunction to CHD phenotypes. Methods: We performed an integrative narrative review of genetic, experimental, and developmental studies focusing on the role of primary and motile cilia in cardiac morphogenesis. Particular attention was given to signaling pathways regulated by cilia and their contribution to disease phenotypes. Results: Emerging evidence indicates that primary and motile cilia act as central regulators of cardiac development, integrating morphogen gradients and mechanical cues into transcriptional programs. Dysfunctions in ciliary structure or signaling are increasingly recognized as important contributors to selected complex CHD phenotypes, particularly in syndromic forms and laterality-associated defects. This cilia-centered model may help explain part of the phenotypic heterogeneity observed in CHD and highlights shared mechanisms across distinct clinical entities. Conclusions: Understanding cilia-dependent mechanisms provides a unifying conceptual framework linking genetic defects to disrupted morphogenesis. This perspective may refine disease interpretation and support future development of precision diagnostics and pathway-informed therapeutic strategies in CHD.
Tetralogy of Fallot: Genetic, Epigenetic and Clinical Insights into a Multifactorial Congenital Heart Disease Maria Felicia Gagliardi, Emanuele Micaglio, Angelo Micheletti, Sara Benedetti, Diana Gabriela Negura, et al. Genes, 2026 Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart disease, classically characterized by right ventricular outflow tract obstruction, ventricular septal defect, overriding aorta, and right ventricular hypertrophy. Recent advances in molecular and genomic research indicate that TOF is part of a phenotypic continuum encompassing Trilogy, Tetralogy, and Pentalogy of Fallot, in which the variability of anatomical presentation reflects shared genetic and epigenetic mechanisms with highly variable penetrance and expressivity. Variants in NOTCH1, FLT4, KDR, GATA6, and TBX1 highlight key pathways in conotruncal development and endothelial–mesenchymal transition, yet these well-known genes explain only a fraction of the genetic landscape. Emerging studies have identified additional candidate genes and networks involved in cardiac morphogenesis, including transcriptional regulators, signaling mediators, chromatin-remodeling factors, and splicing-associated genes such as PUF60 and DVL3. Epigenetic mechanisms, including DNA methylation, histone modifications, and non-coding RNA expression, further modulate phenotypic expressivity and contribute to variability along the Trilogy–Tetralogy–Pentalogy spectrum. This review integrates current genomic and clinical evidence to provide a comprehensive overview of the molecular architecture of Fallot-type conotruncal malformations, emphasizing the interplay between genetic and epigenetic mechanisms, genotype–phenotype correlations, and implications for diagnosis, risk stratification, counseling, and personalized management in the era of precision cardiology.
When Paying Attention Pays Back: Missense Mutation c.1006G>A p. (Val336Ile) in PRKAG2 Gene Causing Left Ventricular Hypertrophy and Conduction Abnormalities in a Caucasian Patient: Case Report and Literature Review Emanuele Micaglio, Lara Tondi, Sara Benedetti, Maria Alessandra Schiavo, Antonia Camporeale, et al. International Journal of Molecular Sciences, 2024 PRKAG2 cardiomyopathy is a rare genetic disorder that manifests early in life with an autosomal dominant inheritance pattern. It harbors left ventricular hypertrophy (LVH), ventricular pre-excitation and progressively worsening conduction system defects. Its estimated prevalence among patients with LVH ranges from 0.23 to about 1%, but it is likely an underdiagnosed condition. We report the association of the PRKAG2 missense variant c.1006G>A p. (Val336Ile) with LVH, conduction abnormalities (short PR interval and incomplete right bundle branch bock) and early-onset arterial hypertension (AH) in a 44-year-old Caucasian patient. While cardiac magnetic resonance (CMR) showed a mild hypertrophic phenotype with maximal wall thickness of 17 mm in absence of tissue alterations, the electric phenotype was relevant including brady–tachy syndrome and recurrent syncope. The same variant has been detected in the patient’s sister and daughter, with LVH + early-onset AH and electrocardiographic (ECG) alterations + lipothymic episodes, respectively. Paying close attention to the coexistence of LVH and ECG alterations in the proband has been helpful in directing genetic tests to exclude primary cardiomyopathy. Hence, identifying the genetic basis in the patient allowed for familial screening as well as a proper follow-up and therapeutic management of the affected members. A review of the PRKAG2 cardiomyopathy literature is provided alongside the case report.
Functional Characterisation of the Rare SCN5A p.E1225K Variant, Segregating in a Brugada Syndrome Familial Case, in Human Cardiomyocytes from Pluripotent Stem Cells Nicolò Salvarani, Giovanni Peretto, Crasto Silvia, Andrea Villatore, Cecilia Thairi, et al. International Journal of Molecular Sciences, 2023 Brugada syndrome (BrS) is an inherited autosomal dominant cardiac channelopathy. Pathogenic rare mutations in the SCN5A gene, encoding the alpha-subunit of the voltage-dependent cardiac Na+ channel protein (Nav1.5), are identified in 20% of BrS patients, affecting the correct function of the channel. To date, even though hundreds of SCN5A variants have been associated with BrS, the underlying pathogenic mechanisms are still unclear in most cases. Therefore, the functional characterization of the SCN5A BrS rare variants still represents a major hurdle and is fundamental to confirming their pathogenic effect. Human cardiomyocytes (CMs) differentiated from pluripotent stem cells (PSCs) have been extensively demonstrated to be reliable platforms for investigating cardiac diseases, being able to recapitulate specific traits of disease, including arrhythmic events and conduction abnormalities. Based on this, in this study, we performed a functional analysis of the BrS familial rare variant NM_198056.2:c.3673G>A (NP_932173.1:p.Glu1225Lys), which has been never functionally characterized before in a cardiac-relevant context, as the human cardiomyocyte. Using a specific lentiviral vector encoding a GFP-tagged SCN5A gene carrying the specific c.3673G>A variant and CMs differentiated from control PSCs (PSC-CMs), we demonstrated an impairment of the mutated Nav1.5, thus suggesting the pathogenicity of the rare BrS detected variant. More broadly, our work supports the application of PSC-CMs for the assessment of the pathogenicity of gene variants, the identification of which is increasing exponentially due to the advances in next-generation sequencing methods and their massive use in genetic testing.
