Genetic Analysis of Children with Dravet Syndrome in a Resourcelimited Setting

Abstract

Objective: To identify the common causal gene mutations in Thai children with the Dravet (DS) phenotype, using single gene analysis. Material and Methods: The study was carried out on 20 DS patients at Siriraj Hospital, Bangkok, Thailand. Sanger sequencing of the Voltage-Gated Sodium Channel Alpha Subunit 1 (SCN1A) gene was conducted in all patients. In SCN1A-negative patients, multiplex ligation-dependent probe amplification of the SCN1A gene was performed in all cases; however, direct sequencing of the Protocadherin-19 (PCDH19) gene was analyzed in girls only. Results: Fourteen (70.0%) DS patients were found to carry pathogenic SCN1A mutations, with 6 novel mutations. In SCNIA-negative patients; 1 of the 4 girl patients (25.0%) had a novel PCDH19 mutation, while none of the 6 patients had a large deletion or duplication in the SCN1A gene. Conclusion: The SCN1A gene is the most common causative mutation in Thai children with DS phenotype. This study emphasizes the benefit of Sanger sequencing of the SCN1A gene in resource-limited countries to aid in making appropriate therapeutic decisions