Unique clinical characteristics and SCN5A mutations in patients with Brugada syndrome in Taiwan

Brugada syndrome (BrS) is a hereditable sudden cardiac death (SCD). Mutationsin the SCN5A gene (the most common BrS-causing gene) are responsible for 20-25% of this disease in Caucasian populations. However, the prevalence of SCN5A mutations inpatientswith BrS in the Chinese Han population in Taiwan remains unknown. Therefore, in this study, we investigated the prevalence of the SCN5A mutation in the largest BrS cohort in Taiwan. Methods: We consecutively enrolled 47 unrelated patients with BrS from medical centers and hospitals in Taiwan between 2000 and 2010. Mutations within all the 27 translated exons, and exon-intron boundaries of the SCN5A-encoded cardiac sodium channel were screened in all patients with BrS using direct sequencing. A total of 500 unrelated healthy volunteers with a normal electrocardiogram were genotyped as a control group. Results: SCN5A genetic variants were identified in 14 of the 47 patients with BrS and four of the 14 patients with BrS had missense mutations (1651 G>A, 1776 C>G, 3578 G>A). The prevalence rate of SCN5A mutations was approximately 8% (4/47), which was significantly lower than that reported in Caucasian populations (20-25%; p=0.0007). The average age of these 14 BrS patients with SCN5A variants at diagnosis (12 men and 2 women) was 40±13 years. Four patients experienced SCD, and six presented with seizure or syncope. Only three patients (3/14, 21.4%) had a family history of SCD. Conclusion: The prevalence of SCN5A mutations in the Chinese Han population in Taiwan may be lower than that reported in the Caucasian populations. In addition, most patients with BrS did not have a family history of SCD.