Shen Qi, Wang Zhimin, Lin Junyi, Li Liliang, Zhang Suhua, Wang Shouyu, Li Chengtao
School of Forensic Medicine, Shanxi Medical University, Jinzhong, 030600, China.
Institute of Forensic Science, Fudan University, Shanghai, 200032, China.
Int J Legal Med. 2025 Sep 16. doi: 10.1007/s00414-025-03575-2.
Genetic factors are known to have important roles in sudden unexplained death (SUD) of apparently healthy individuals. Currently, molecular autopsy is considered an effective diagnostic tool in the multidisciplinary management of SUD. Recent studies highlighted the contribution of regulatory variants to complex genetic disorders. Pathogenic variants within the untranslated regions of SUD susceptibility genes were also identified in certain cases. However, the functional validation of pathogenic variants outside of the coding regions remains challenging. As the most direct method, transcriptome analysis could be performed at the same time with molecular autopsy to identify the abnormal expression of SUD susceptibility genes, while the post-mortem degradation of mRNA in myocardial tissues has made it difficult to interpret the transcriptome profiling results. In this study, we performed a retrospective analysis-based prioritization of SUD susceptibility genes based on the distribution of pathogenic genetic variants in previous studies with molecular autopsy findings reported. After gene prioritization, we analyzed the transcriptome data of 432 left ventricle tissues with different sampling time intervals from the Genotype-Tissue Expression database, in order to characterize the degradation pattern of prioritized SUD susceptibility genes. Furthermore, RNA degradation difference between unfrozen and thawed samples was investigated. We demonstrated that with proper segmentation of genes according to their degradation patterns, a partial least squares-discriminant analysis could effectively recognize the expression difference of targeted genes between normal samples and simulated SUD cases. Taken together, our findings presented a strategy for the interpretation of RNA profiling results during the forensic investigation of SUD.
已知遗传因素在表面健康个体的不明原因猝死（SUD）中起重要作用。目前，分子尸检被认为是SUD多学科管理中的一种有效诊断工具。最近的研究强调了调控变异对复杂遗传疾病的贡献。在某些病例中还鉴定出SUD易感基因非翻译区内的致病变异。然而，编码区以外致病变异的功能验证仍然具有挑战性。作为最直接的方法，转录组分析可以与分子尸检同时进行，以识别SUD易感基因的异常表达，而心肌组织中mRNA的死后降解使得难以解释转录组分析结果。在本研究中，我们基于先前报道的分子尸检结果的研究中致病基因变异的分布，对SUD易感基因进行了基于回顾性分析的优先级排序。在基因优先级排序后，我们分析了来自基因型-组织表达数据库的432个不同采样时间间隔的左心室组织的转录组数据，以表征优先级SUD易感基因的降解模式。此外，还研究了未冷冻和解冻样品之间的RNA降解差异。我们证明，根据基因的降解模式进行适当的分割，偏最小二乘判别分析可以有效地识别正常样品和模拟SUD病例之间靶向基因的表达差异。综上所述，我们的研究结果提出了一种在SUD法医调查期间解释RNA分析结果的策略。
