Identification of a Novel SCN5A gene variant in a young female with atrioventricular canal defect in the absence of classical Brugada syndrome phenotype.

Background: Brugada syndrome is generally considered a cardiac channelopathy disorder characterized by syncope or sudden cardiac death. The sodium voltage-gated channel alpha subunit 5 (SCN5A) gene is the most commonly mutated gene associated with Brugada syndrome. Recent discoveries of new variants of this gene, along with current guidance of family screening, have identified several asymptomatic carriers with potentially causative mutations.

Case presentation: We present the case of a 25-year-old female patient without any family history of Brugada syndrome nor related congenital cardiovascular disorders, with an extensive atrioventricular canal defect, who tested positive for a novel heterozygous variant NM_198056.3: c.3169G>C (p. Asp1057 His) in the SCN5A gene. She had no history of syncope or aborted sudden cardiac death except for recurrent chest infections since her early childhood. Intriguingly, she did not show a type I Brugada electrocardiogram pattern.

Conclusions: This report provides a novel heterozygous variant NM_198056.3: c.3169G>C (p. Asp1057 His) in the SCN5A gene, which may have a potential detrimental effect.