汉族人群NUP155基因突变导致房颤和心律失常性猝死的遗传筛查及机制研究

Sudden cardiac death is very common in forensic medical examination, within these cases, causes of arrhythmic sudden cardiac death without structural lesions are all through difficult to disclose. Under present basic theories and technologies, legal medical experts have no choice but to conclude such cases as “sudden unexplained death syndrome”, after they have eliminated all possibilities of death. .It is well known that ventricular arrhythmia, caused by mutations of ion channel or the functionally related protein coding genes, leads to sudden cardiac death. A present study revealed that a homozygous point mutation R391H barbered in nuclear pore component coding gene NUP155 (not ion channel and has no directly functional relevance with ion channel), leaded to heritable atrial fibrillation and early sudden cardiac death in a white family. This result provided new evidence to support the viewpoint that arrhythmic sudden cardiac death is triggered by mutation of but not limited ion channel. .However, the bellowing questions still remain to be answered: Firstly, whether mutated NUP155 causes atrial fibrillation and arrhythmic sudden cardiac death in population? Secondly, what are the cellular electrophysiological mechanism and molecular mechanism under which mutated NUP155 triggers atrial fibrillation and sudden cardiac death? And are there any differences among different mutation sites? Thirdly, is there ventricular arrhythmia which connects NUP155-caused atrial fibrillation and sudden death? This project intends to clarify these issues using a serious of strategies and technologies of genetic screening, molecular biology, electrophysiology and transgenic mouse model, in order to enrich the Etiologic theory about arrhythmic sudden cardiac death, and to provide theoretic base for the prevention and treatment of atrial fibrillation and for the medicolegal diagnosis of arrhythmic sudden cardiac death.

无器质性病变的心律失常性猝死一直是法医学死因鉴定中的难题。 离子通道基因突变可致室性心律失常性猝死已成为学术界共识。申请人前期课题组研究发现：非离子通道的NUP155纯合突变R391H导致了一家族的遗传性房颤和无器质性病变的心律失常性猝死。本项目在此基础上提出新的科学问题：①NUP155是否散发房颤和心律失常性猝死的易感基因？②NUP155突变导致房颤和心律失常性猝死的机制是什么？③NUP155突变导致的房颤和猝死之间有无室性心律失常介入？本项目拟：①收集汉族散发房颤和法医学猝死样本，采用DNA测序技术筛查NUP155突变；②将突变型NUP155在心房肌细胞过表达，行膜片钳实验和分子生物学实验；③实时动态监测突变型NUP155转基因鼠的心电活动及猝死现象。以阐明上述科学问题，以期进一步丰富心律失常性猝死的病因学理论，为此类房颤的防治、心律失常性猝死的早期识别和法医学诊断研究提供科学依据。

无器质性病变的心律失常性猝死一直是法医学死因鉴定中的难题。离子通道基因突变可致室性心律失常性猝死已成为学术界共识。申请人前期课题组研究发现：非离子通道的NUP155纯合突变R391H导致了乌拉圭一个近亲婚配的白人家族的遗传性房颤和婴幼儿猝死。本项目在此基础上进一步在中国汉族散发原发性心律失常患者和被诊断为不明原因猝死综合征死者样本中筛查NUP155基因突变。采用针对所有已知心律失常致病基因的基因芯片，通过对40例不明原因猝死综合征（尸体解剖、组织病理学检查、毒物化验等结果均为阴性，结合现场勘验和案情调查等，法医学死因鉴定结论为符合心律失常猝死的）死者心血样本的基因检测，在2名青壮年猝死样本中筛查到NUP155基因2个新的杂合型突变位点：c.4051A>G (p.N1351D)、c.1507C>T (p.L503F)；对48例临床诊断为原发性心律失常患者血液样本的基因检测，筛查到NUP155另外2个新的杂合型突变位点：一名复极综合征患者携带c.2995_3012delCCTGGTCCTCCAGTGTTG (p.P999_L1004del)突变，一名房室结折返性心动过速36岁男性患者携带c.485G>A (p.R162Q)突变。在200名正常对照人群中未发现相关突变。进一步电子突变功能分析显示c.1507C>T (p.L503F)和c.2995_3012delCCTGGTCCTCCAGTGTTG (p.P999_L1004del)为功能有害突变。结果提示NUP155是中国汉族散发原发性心律失常和心律失常性猝死的易感基因。研究提供了新的NUP155与心律失常关联的分子遗传学证据，进一步丰富了心律失常及其导致的猝死的基因突变谱，为心律失常性猝死的个体化早期预警和法医学诊断提供了科学依据。