Brugada syndrome is characterized by right bundle branch block and ST-segment 
elevation in the right precordial ECG leads. Familial transmission is frequent 
and approximately 25% of cases exhibit mutations in the SCN5A gene. We analyzed 
the sequence of this gene in 25 Spanish patients with Brugada syndrome. In 4 
(16%), we found mutations that had not previously been described: three were 
amino acid changes (i.e. Ala2>Thr, Ala735>Thr and Val1340>Ile) and one was an 
intron mutation that affected messenger RNA processing (i.e. IVS18-1G>A). These 
four patients had relatives who were also mutation carriers, several of whom had 
normal ECGs, even on flecainide challenge. Our study suggests that genetic 
analysis could be helpful in the presymptomatic diagnosis of Brugada syndrome, 
but may be less useful for stratifying the risk of adverse events.