Epidemiology of Channelopathies in a Mediterranean Pediatric Population

Background: Channelopathies represent a heterogeneous group of rare inherited cardiac diseases associated with life-threatening arrhythmias. Our knowledge of their epidemiology in childhood is limited. The aim of this study is to evaluate the epidemiology of pediatric channelopathies on a Mediterranean island (Crete, Greece). Methods: Retrospective study of children < 18 years followed in the Regional Tertiary Pediatric Cardiology Unit during a 23-year period (2002-2024) and meeting the disease-specific diagnostic criteria. Results: A total of 34 children (27 families) were enrolled, corresponding to an average annual incidence of 1.2 (95% C.I.: 0.8 – 1.6) and a cumulative prevalence of 23.9 (95% C.I.: 16.1 – 34.1) cases per 100, 000 children, with significant though regional incidence differences. Long QT syndrome (n=33) was predominant, with a single exception of catecholaminergic polymorphic tachycardia. Diagnosis was based on symptomatic presentation (n=15, 44 %), preparticipation screening (n=6, 18%) or affected family cascade screening (n=13, 38%). They represented the first diagnosis within affected families (index cases) in 20/34 (58%) of cases. Genetic testing was performed in 27/34 (79%) channelopathy cases and it was positive in a single case of CPVT and in 23 out of 27 (89%) LQT cases in which it was performed, with a genotype of LQT2 in 13 (39%), LQT1 in 7 (21%), LQT3 in 1 (3%) and LQT5 in 2 (6%) cases. Conclusion: The incidence of pediatric channelopathies on the Mediterranean island of Crete was comparable to that reported in the literature, with regional though clusters of significant increased incidence. Further study of the epidemiology of pediatric channelopathies is needed, to document any regional or ethnic differences and for the best design of large-scale screening programs.