RESUMO
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.
Assuntos
Arritmias Cardíacas/genética , Síndrome do QT Longo/genética , Canal de Sódio Disparado por Voltagem NAV1.8/genética , Síncope/genética , Adulto , Idoso , Arritmias Cardíacas/fisiopatologia , Análise Mutacional de DNA , Feminino , Mutação da Fase de Leitura , Frequência do Gene , Predisposição Genética para Doença , Testes Genéticos , Humanos , Síndrome do QT Longo/fisiopatologia , Masculino , Pessoa de Meia-Idade , Linhagem , Fenótipo , Síncope/fisiopatologiaRESUMO
New Zealand, like other southern hemisphere countries with a temperate climate, has been in the winter period with seasonal influenza activity. New Zealand has also experienced a dramatic increase in the number of cases of pandemic influenza A(H1N1)v virus. Early reports from the northern hemisphere at the beginning of the pandemic showed that the virus was sensitive to the antiviral drug oseltamivir. In this study we report that pandemic influenza A(H1N1)v viruses currently circulating in New Zealand are sensitive to oseltamivir, but seasonal influenza A(H1N1) viruses - the co-circulating predominant seasonal strain, is resistant to oseltamivir.