Researchers have identified six genetic variants in the SCN5A gene among Malaysian adults diagnosed with Brugada syndrome, marking a critical step forward in addressing regional data gaps in inherited cardiac conditions that can lead to sudden cardiac death.
Genetic analysis of Malaysian adults evaluated through a multicentre case-control study has revealed new insights into an inherited heart rhythm disorder long recognized across Southeast Asia. The investigation drew on patients recruited from tertiary cardiology centres nationwide, establishing diagnoses through electrocardiogram-confirmed patterns that included Type 1, Type 2, and Type 3 presentations. Healthy individuals with normal ECG findings and no family history of sudden cardiac death served as controls, providing a baseline for genomic DNA extraction from peripheral blood samples.
Genetic Variants and Clinical Diversity in the Study Population
The study, which examined 40 patients, identified six distinct variants within the SCN5A gene—the primary genetic driver known to encode the Nav1.5 cardiac sodium channel. These genetic alterations fell across various clinical classifications, encompassing pathogenic, likely pathogenic, uncertain significance, and benign categories. Notably, the variant designated as p. Arg965Cys appeared in 12.5% of the evaluated cases.
Alongside these genomic findings, the cohort displayed wide-ranging symptom profiles that showed the condition's clinical heterogeneity. Palpitations emerged as the most frequently reported symptom, affecting 47.5% of the participants. Other reported experiences included chest pain at 37.5%, presyncope at 35.0%, syncope at 32.5%, and dizziness affecting 30.0% of individuals, while seizure-like episodes were documented in 7.5% of cases.
Inherited Cardiac Channelopathy Increases Ventricular Fibrillation Risk
Brugada syndrome functions as an inherited cardiac channelopathy characterized by a distinctive right precordial ECG configuration and an elevated vulnerability to ventricular fibrillation. Electrophysiological disturbances within the right ventricular outflow tract, frequently compounded by subtle structural shifts and fibrotic changes, establish the substrate necessary for re-entrant arrhythmias. External modulators such as fever, autonomic fluctuations, and inflammatory mediators are understood to unmask or intensify the ECG phenotype by altering cellular signalling pathways and channel kinetics.
Global diagnostic frameworks increasingly integrate polygenic risk profiling alongside clinical histories and provocative drug testing. Advanced approaches now encompass stratified scoring systems designed to gauge the pathogenicity of rare genetic variants by synthesizing population allele frequencies, in silico predictions, family segregation data, and functional assays. Within Malaysia, researchers note that while the findings support incorporating genetic testing into risk stratification and family screening protocols, individual variants do not yet independently predict imminent ventricular arrhythmias or sudden cardiac death.