Abstract 14356: Blood Tests That Improve the Accuracy of a Brugada Syndrome Diagnosis

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Objectives: To discover the role of altered gene expression regulation in Brugada Syndrome (BrS) and to find biomarkers for BrS diagnosis. Methods: Twenty-five control patients (Control), 25 BrS patients without SCN5A mutation (SCN5A(-)) and 20 BrS patients with SCN5A mutation (SCN5A(+)) were included in this study. Specified gene expression of white blood cells (WBC) were measured by RT-qPCR using TaqMan® Gene Expression assay. Results: MEF2C and MESP1 are the two major cardiac specific transcription factors expressed in WBC. The mRNA expression levels of SCN5A, MEF2C and HuR, one of mRNA stabilizers, were decreased in the SCN5A (+) group (P=0.047, 0.02, 0.000 vs. control group, respectively). The mRNA expression of MESP1 in WBCs was significantly lower in both SCN5A(-) (P=0.012 vs. control) and SCN5A(+) (P=0.000 vs. control) groups. There was no difference between the two BrS groups in MESP1 expression (P=0.215). The area under the Receiver Operating Characteristics (ROC) analysis curve for prediction of BrS using MESP1 levels was 0.775 (95% CI 0.668, 0.882, asymptotic Sig.=0.000). At the optimal cutoff, the corresponding maximum sensitivity and specificity were 0.62 (95% CI: 0.47, 0.76) and 0.88 (0.69, 0.97), respectively. The diagnostic odds ratio (DOR) of MESP1 for BrS diagnosis was 11.96 (95% CI: 5.79, 24.73). The assessment of the mRNA levels in blood SCN5A, MEF2C and HuR were useful for predicting BrS patients with an SCN5A mutation. The area under the ROC analysis curve for prediction of BrS with an SCN5A mutation using SCN5A, MEF2C and HuR mRNA levels in WBCs was 0.847 (95% CI 0.752, 0.942, asymptotic Sig.=0.000), 0.685 (95% CI 0.542, 0.828, asymptotic Sig.=0.016) and 0.777 (95% CI 0.652, 0.902, asymptotic Sig.=0.000), respectively. At the optimal cutoff, the DOR of SCN5A, MEF2C and HuR for SCN5A(+) BrS diagnosis was 17.5 (95% CI: 8.06, 37.86), 4.9 (95% CI: 2.61, 9.17) and 23.5 (95% CI: 9.39, 58.80), respectively. Conclusions: Our results suggest that assessment of circulating MESP1 may be used as a biomarker for BrS diagnosis while decreased SCN5A, MEF2C and HuR mRNA in WBCs is associated with BrS patients with an SCN5A mutation. Our results also suggest that decreased expression of SCN5A, MEF2C, MESP1, and HuR may be pathophysiologically related to BrS.