Genetic landscape of paediatric channelopathies and cardiomyopathies in Hong Kong

INTRODUCTION: Cardiac channelopathies and cardiomyopathies are important causes of sudden cardiac death. The genetic background of these conditions in Asian paediatric populations has rarely been reported. This study aimed to report the genetic underpinnings of these conditions in patients treated at a single tertiary paediatric cardiac centre in Hong Kong. METHODS: All patients diagnosed with cardiac channelopathy or cardiomyopathy who underwent genetic testing in our cardiology centre between 2007 and 2022 were included in this cohort study. Phenotype classification, genetic testing methodologies, and results were reviewed. Genetic yields were assessed. RESULTS: In total, 165 probands were identified. Ninety-four probands carried at least one pathogenic or likely pathogenic (P/LP) variant (57.0%), whereas 27 probands (16.4%) had only variants of uncertain significance (VUS). Pathogenic or likely pathogenic variants were identified in 58 patients with channelopathy (63.7%) and 36 patients with cardiomyopathy (48.6%), including 22 novel variants (16 P/LP variants and 6 VUS). The yield of P/LP variants was highest in catecholaminergic polymorphic ventricular tachycardia (81.8%). The clinical features of selected probands with significant mortality or morbidity were described in relation to variant details. The yield of subsequent cascade genetic screening among first-degree relatives was 27.3%. CONCLUSION: This study describes the genetic landscape of paediatric cardiac channelopathies and cardiomyopathies at a single tertiary paediatric cardiology centre in Hong Kong. The findings facilitated genotype-guided management and enabled identification of at-risk family members for the prevention of sudden cardiac death.