QTc prolongation is reported in patients with hypertrophic cardiomyopathy (HCM). However, the causes of the QTc interval increase remain unclear. The main contribution to QTc prolongation in HCM is attributed to the myocardial hypertrophy and related structural damage. In a 24-year-old male proband, affected by HCM and long QTc, we identified by Next Generation Sequencing a pathogenic variant in gene TNNI3 co-inherited with a damaging variant in KCNQ1 gene. This evidence suggests the possibility that QTc interval prolongation and its dispersion in HCM could be associated not only to the severity of left ventricular hypertrophy but also to the co-inheritance of pathogenic variants related to both long QT Syndrome (LQTS) and HCM. Although the simultaneous presence of pathogenic variants in genes related to different heart diseases is extremely rare, counseling and genetic testing appear crucial for the clinical diagnosis. Screening of LQTS genes should be considered in HCM patients to clarify the origin of long QTc, to provide more information about the clinical presentation and to evaluate the incidence of the co-existence of LQTS/HCM gene variants that could occur more frequently than so far reported.

据报道，肥厚型心肌病（HCM）患者的QTc延长。但是，QTc间隔增加的原因仍不清楚。HCM中QTc延长的主要贡献归因于心肌肥大和相关的结构损伤。在受HCM和长QTc影响的24岁男性先证者中，我们通过“下一代测序”鉴定了基因TNNI3中的致病变异与KCNQ1中的有害变异共同遗传基因。这一证据表明，QTc间隔延长及其在HCM中的扩散可能不仅与左心室肥大的严重程度有关，而且与与长QT综合征（LQTS）和HCM相关的病原体变异体的共遗传有关。尽管在与不同心脏病相关的基因中同时存在致病性变体极为罕见，但咨询和基因检测对于临床诊断显得至关重要。在HCM患者中应考虑筛查LQTS基因，以阐明长QTc的起源，提供有关临床表现的更多信息，并评估可能比迄今为止更频繁发生的LQTS / HCM基因变体共存的发生率报告。