迄今仍有约80%的不明原因猝死（SUD）的分子病因未能阐明。前期研究中申请人在小样本SUD死者中发现了DSP基因的重要遗传变异，在两个无关Brugada综合征（BrS）患者中发现了DSP的同一突变p.R315C，并在预实验发现该突变可引起心肌细胞电生理学异常。据此我们提出科学假设：DSP基因变异可能是SUD新的分子病因。本项目拟开展系统的DSP分子病理学研究，在SUD死者和BrS患者中寻找DSP可疑致病变异。此外，应用p.R315C突变携带患者iPSC来源的心肌细胞，通过RT-qPCR、免疫印迹、免疫荧光、突变修复、膜片钳、RNA-seq和生物信息学技术研究p.R315C突变对DSP、CX43和钠离子通道蛋白表达及亚细胞定位的影响，解析p.R315C突变导致SUD的分子生物学及电生理学机制，为SUD的早期筛查和预防提供分子病理学依据，为法医学SUD死因鉴定实践提供新的思路和方法。

Sudden unexplained death (SUD) remains an autopsy negative disorder with unclear etiology. In our preliminary study, DSP rare heterozygous variants were found in SUD victims and a DSP mutation p.R315C was found in two unrelated Brugada syndrome (BrS) patients. Further, we detected abnormal electrophysiology in induced pluripotent stem cells (iPSC) derived cardiomyocytes which belong to a BrS patient who harbor the mutation p.R315C without pathogenic variants in other known arrhythmia-causing genes. According to the above studies, we hypothesized that DSP variants were genetic causes of some SUD cases. To verify this hypothesis, we intend to screen DSP gene variants among SUD victims and BrS patients. Further, we intend to test DSP-p.R315C variant in BrS patient specific iPSC derived cardiomyocytes. We attempt to investigate the structure and function of DSP, CX43 and sodium ion channel by quantitative real-time PCR, Western Blotting, immunofluorescence, mutation editing, patch clamp, RNA-seq and bioinformatic analysis, in order to dissect the molecular pathological and electrophysiological mechanisms of DSP-p.R315C variant induced SUD, which may offer some important information for early diagnosis, therapy and prognosis of SUD, and provide insights to identification of SUD cases.