Application of RNA sequencing to cause-of-death investigation: A pilot study

Determining the cause of death in forensic autopsies is often challenging, especially when clinical information is limited. RNA analysis has been explored for this purpose, but conventional qRT-PCR approaches are restricted to preselected targets. RNA sequencing (RNA-seq) enables comprehensive transcriptome profiling and may reduce observer bias, yet its application in forensic cause-of-death investigation remains limited.

We applied RNA-seq to two forensic cases: one involving fatal insulin overdose and another involving anaphylactic shock. Gene expression profiles were compared with control cases using relative log expression normalization.

In the insulin overdose case, transcripts in the insulin receptor substrate-PI3K-PDK1/2 pathway and related metabolic cascades were upregulated. In the anaphylaxis case, genes downstream of FcεRI signaling (VAV, IL-3, IL-4, GM-CSF, p38, cPLA2) and T cell receptor-associated molecules showed increased expression.

This proof-of-concept pilot study suggests that RNA-seq can capture molecular signatures associated with specific causes of death. These findings indicate the potential of transcriptomic profiling as a complementary tool in forensic diagnostics when conventional methods are inconclusive.