Key result
Rare deleterious SCN10A mutations linked to ~91-fold higher odds of prolonged QT.
Why the study?
Are deleterious mutations in the SCN10A gene associated with prolonged QT syndrome?
Case-Control (n=60,722)
Are deleterious mutations in the SCN10A gene associated with prolonged QT syndrome?
Deleterious frameshift and missense mutations in the SCN10A gene are associated with prolonged QT syndrome, implicating it as a novel LQT gene.
Answers are grounded in this paper and cite their sources.
SCN10A testing not indicated in LQT; small case series leaves causal role hypothesis-generating pending replication.
BACKGROUND: Long QT syndrome (LQT) is a pro-arrhythmogenic condition with life-threatening complications. Fifteen genes have been associated with congenital LQT, however, the genetic causes remain unknown in more than 20% of cases. MATERIALS AND METHODS: Eighteen patients with history of palpitations, pre-syncope, syncope and prolonged QT were referred to the Yale Cardiovascular Genetics Program. All subjects underwent whole-exome sequencing (WES) followed by confirmatory Sanger sequencing. Mutation burden analysis was carried out using WES data from 16 subjects with no identifiable cause of LQT. RESULTS: Deleterious and novel SCN10A mutations were identified in 3 of the 16 patients (19%) with idiopathic LQT. These included 2 frameshifts and 1 missense variants (p.G810fs, p.R1259Q, and p.P1877fs). Further analysis identified 2 damaging SCN10A mutations with allele frequencies of approximately 0.2% (p.R14L and p.R1268Q) in 2 independent cases. None of the SCN10A mutation carriers had mutations in known arrhythmia genes. Damaging SCN10A mutations (p.R209H and p.R485C) were also identified in the 2 subjects on QT prolonging medications. CONCLUSION: Our findings implicate SCN10A in LQT. The presence of frameshift mutations suggests loss-of-function as the underlying disease mechanism. The common association with atrial fibrillation suggests a unique mechanism of disease for this LQT gene.
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Ziki et al. (2017) conducted a case-control in Long QT syndrome (Prolonged QT) (n=60,722). Rare deleterious SCN10A mutations (allele frequency <1:100,000) vs. Absence of rare deleterious SCN10A mutations was evaluated on Prolonged QT (OR 90.9, 95% CI 31.4-263.2, p=<0.0001). Rare and deleterious SCN10A mutations were associated with a significantly increased risk of prolonged QT, demonstrating an odds ratio of 90.9 compared to population controls.
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