Sudden Unexplained Death Syndrome (SUDS) (or in Thai Lai-tai) share the same ECG pattern as Brugada Syndrome: RSR' and ST segment elevation in V1 to V3. Brugada Syndrome is a genetic disorder with the inheritance pattern of autosomal dominant (using the ECG pattern and unexplained sudden death as phenotype) and the cardiac sodium channel gene (SCN5A) mutations caused this syndrome. To determine whether SUDS was associated with the same mutations as Brugada Syndrome, the authors performed a linkage studies on 5 SUDS families with the Brugada Syndrome ECG pattern and found one family could not be excluded from linkage to SCN5A. However, the direct sequencing in 8 reported mutations on exon 5, 12, 17, 18 and 28 in this family failed to demonstrate the mutations. It was concluded that SUDS mutations maybe a novel mutation different from previously reported mutations, further genetic studies in SCN5A and other candidate genes might elucidate the molecular basis of SUDS.