Epigenetic Components of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Uncover Potential Transposable Element Activation.
Almenar-Pérez, Eloy, Ovejero, Tamara, Sánchez-Fito, Teresa et al. · Clinical therapeutics · 2019 · DOI
Quick Summary
This study reviewed research on how ME/CFS may involve changes in how genes are regulated, not the genes themselves. The researchers discovered that dormant DNA sequences called transposable elements—which make up almost half of our genome and were previously thought to be 'junk DNA'—might become activated in ME/CFS patients. This activation could trigger the immune system to attack without an actual infection present.
Why It Matters
This work offers a novel mechanistic hypothesis that could explain why ME/CFS patients experience persistent immune activation without detectable pathogens. If transposable element activation is confirmed, it could open entirely new avenues for targeted diagnostics and therapeutic interventions designed to suppress aberrant TE transcription.
Observed Findings
Methylation patterns in ME/CFS patients differ significantly from healthy controls
Noncoding RNA profiles of immune cells show differential expression in ME/CFS
Transposable elements are associated with epigenetic hallmarks identified in ME/CFS
Transposable elements represent >45% of the human genome but are often filtered out of standard genomic analyses
Epigenetic changes may trigger innate immune activation without active infection
Inferred Conclusions
Dormant transposable elements may be abnormally activated in ME/CFS, potentially explaining immune system dysfunction
Standard genomic analysis methods that exclude repetitive sequences may be missing important disease mechanisms
A model of ME/CFS pathogenesis should incorporate transcriptional induction of endogenous retroelements and RNA-mediated immune activation
Large-scale epigenetic datasets from ME/CFS patients are needed to design empirical studies testing TE involvement
Remaining Questions
Can transposable element activation be directly confirmed in ME/CFS patient samples using functional assays?
What This Study Does Not Prove
This systematic review does not establish causation—it identifies associations between epigenetic patterns and TEs that warrant further investigation. The proposed transposon activation mechanism remains a hypothesis requiring direct experimental validation in ME/CFS patient samples. The study does not prove that TE activation alone explains ME/CFS pathogenesis, as the disease likely involves multiple contributing factors.