Dual phenotypic transmission in Brugada syndrome.

Background: Brugada syndrome is a genetic heart disease with autosomal dominant inheritance. Family screening commonly detects one parent responsible for transmission of the disease.

Aims: To describe atypical transmission of Brugada syndrome.

Methods: Between 2001 and 2007, systematic screening, including an electrocardiogram, ajmaline challenge and DNA sequencing of the SCN5A gene, of the first-degree relatives of 62 probands with Brugada syndrome was performed (Programme Hospitalier de Recherche Clinique).

Results: In two families, both parents transmitted Brugada syndrome to their offspring. In the first family, the proband presented Brugada electrocardiogram features with ajmaline challenge and carried a new SCN5A mutation (p.V1281F). The mutation was also identified in the mother, who had a type 1 aspect on inferior leads with ajmaline. The proband's father presented a typical Brugada electrocardiogram pattern on lead V2 with ajmaline and no SCN5A gene mutation. In the second family, the proband was a boy aged 2.5 years who had been resuscitated from sudden cardiac death. Ajmaline challenge revealed a typical Brugada electrocardiogram pattern in both parents but with no mutation in the genes studied.

Conclusion: Family studies should always be exhaustive and discovery of one parent with Brugada syndrome does not eliminate the need for screening of the other parent.