单纯型和复合型长QT综合征3型患者的基因与临床特征研究

Genetic and clinical characteristics of single and compound types of patients with long QT syndrome type 3

目的:探讨长QT综合征3型(LQT3)患者的遗传背景及临床特征。方法:本研究为回顾性队列研究。选取1998年1月至2022年12月于武汉大学人民医院心内科就诊的经基因检测确诊的LQT3患者,根据是否携带单个SCN5A基因突变分为单纯型组与复合型组,对两组患者进行随访并比较两组患者及先证者的基线特征、心电图及临床事件的差异。采用Kaplan-Meier曲线进行生存分析,并使用log-rank检验比较两组患者及先证者无首次心脏事件发生率的差异。结果:共纳入97例LQT3患者(含先证者59例),诊断年龄(23.45±19.86)岁,男性46例(47.4%)。其中单纯型组89例,复合型组8例。基因检测发现了49个SCN5A基因突变,绝大部分是错义突变(91.8%),主要分布在跨膜区(40.8%, n=20)、连接区(28.6%, n=14)和C端(22.4%, n=11)。44例(45.4%)患者发生首次心脏事件,发病年龄(13.82±12.50)岁,诱因主要是休息或睡眠(54.5%, n=24)。与单纯型组相比,复合型组诊断年龄较小[(10.35±10.28)岁比(24.63±20.13)岁, P=0.040],出现晕厥[87.5%(7/8)比33.7%(30/89), P=0.009]、心搏骤停幸存[62.5%(5/8)比11.2%(10/89), P=0.001]的患者比例较高,无首次心脏事件发生率较低[12.5%(1/8)比58.4%(52/89),log-rank P=0.001]。复合型LQT3先证者出现心搏骤停幸存的比例显著高于单纯型LQT3先证者[62.5%(5/8)比17.6%(9/51), P=0.020],两组无首次心脏事件发生率差异无统计学意义[12.5%(1/8)比39.2%(20/51),log-rank P=0.08]。 结论:复合型LQT3在LQT3中并不少见,该类患者被诊断年龄更小,且表型更严重,在临床诊疗中需要密切的随访以及更积极的干预策略。

ObjectiveTo explore the genetic background and clinical features of patients with long QT syndrome type 3(LQT3).MethodsThis retrospective cohort included patients diagnosed with LQT3 at the Department of Cardiology,Renmin Hospital of Wuhan University from January 1998 to December 2022.Patients were categorized into compound type group and single type group based on the presence of a single SCN5A mutation.The two groups were followed up and the differences in baseline characteristics,electrocardiograms,and clinical events between the two groups and probands were compared.Kaplan-Meier curves were used for survival analysis,and the log-rank test was employed to compare the event-free survival rates of first cardiac events between the groups and probands.ResultsA total of 97 LQT3 patients were enrolled,including 59 probands.The age at diagnosis was(23.45±19.86)years,with 46 patients(47.4%)being male.Among them,89 patients were classified as single type group,while 8 patients were classified as compound type group.Genetic testing identified 49 SCN5A mutations,with missense mutations being the majority(91.8%),primarily located in transmembrane regions(40.8%,n=20),interdomain linker regions(28.6%,n=14),and C-terminus(22.4%,n=11).The first cardiac event occurred in 44 patients(45.4%),with an onset age of(13.82±12.50)years.The main trigger was identified as rest or sleep(54.5%,n=24).Compared with patients in single type group,patients in compound type group were younger at diagnosis((10.35±10.28)years vs.(24.63±20.13)years,P=0.040),had a significantly higher proportion of syncope(87.5%(7/8)vs.33.7%(30/89),P=0.009),aborted cardiac arrest(62.5%(5/8)vs.11.2%(10/89),P=0.001),and a lower incidence of event-free survival rates of first cardiac events(12.5%(1/8)vs.58.4%(52/89),log-rank P=0.001).The probands in compound type group had a significantly higher proportion of aborted cardiac arrest comparing to probands in single type group(62.5%(5/8)vs.17.6%(9/51),P=0.020),while the difference in the incidence rate of event-free survival rates of first cardiac events between the probands in two groups was not statistically significant(12.5%(1/8)vs.39.2%(20/51),log-rank P=0.08).ConclusionCompound type LQT3 patients are not uncommon.Such patients are diagnosed at a younger age and exhibit more severe phenotypes,requiring close follow-up and proactive intervention strategies.