Mutation Type and a Genetic Risk Score Associate Variably With Brugada Syndrome Phenotype in Families.

BACKGROUND

Brugada syndrome (BrS) is characterized by the type 1 Brugada ECG pattern. Pathogenic rare variants in (mutations) are identified in 20% of BrS families in whom incomplete penetrance and genotype-negative phenotype-positive individuals are observed. E1784K- is the most common mutation identified. We determined the association of a BrS genetic risk score (BrS-GRS) and mutation type on BrS phenotype in BrS families with mutations.

METHODS

Subjects with a spontaneous type 1 pattern or positive/negative drug challenge from cohorts harboring mutations were recruited from 16 centers (n=312). Single nucleotide polymorphisms previously associated with BrS at genome-wide significance were studied in both cohorts: rs11708996, rs10428132, and rs9388451. An additive linear genetic model for the BrS-GRS was assumed (6 single nucleotide polymorphism risk alleles).

RESULTS

In the total population (n=312), BrS-GRS ≥4 risk alleles yielded an odds ratio of 4.15 for BrS phenotype ([95% CI, 1.45-11.85]; =0.0078). Among -positive individuals (n=258), BrS-GRS ≥4 risk alleles yielded an odds ratio of 2.35 ([95% CI, 0.89-6.22]; =0.0846). In -negative relatives (n=54), BrS-GRS ≥4 alleles yielded an odds ratio of 22.29 ([95% CI, 1.84-269.30]; =0.0146). Among E1784K- positive family members (n=79), hosting ≥4 risk alleles gave an odds ratio=5.12 ([95% CI, 1.93-13.62]; =0.0011).

CONCLUSIONS

Common genetic variation is associated with variable expressivity of BrS phenotype in families, explaining in part incomplete penetrance and genotype-negative phenotype-positive individuals. mutation genotype and a BrS-GRS associate with BrS phenotype, but the strength of association varies according to presence of a mutation and severity of loss of function.