Changes in DNA methylation profiles of myalgic encephalomyelitis/chronic fatigue syndrome patients reflect systemic dysfunctions.
Helliwell, A M, Sweetman, E C, Stockwell, P A et al. · Clinical epigenetics · 2020 · DOI
Quick Summary
This study looked at chemical tags on DNA called methylation patterns in people with ME/CFS compared to healthy people. These tags can turn genes on or off without changing the DNA itself. Researchers found that people with ME/CFS have different methylation patterns, particularly in genes related to energy production, immune function, and brain chemistry, which may help explain why they experience the symptoms they do.
Why It Matters
This study provides molecular evidence that ME/CFS involves systematic epigenetic changes affecting multiple biological systems, not just isolated abnormalities. Finding consistent patterns across different study methods strengthens the biological basis for ME/CFS and may ultimately lead to new diagnostic biomarkers or therapeutic targets.
Observed Findings
Compared to healthy controls, ME/CFS patients showed 76 differentially methylated DNA fragments and 394 differentially methylated individual cytosines
Four regulatory clusters were identified near genes involved in metabolic and immune activity
122 unique genes showed altered methylation in their gene bodies (exons and introns)
Functional pathway analysis identified 30 enriched pathways related to immune, metabolic, and neurological functions
Approximately 59% of genes identified overlapped with findings from previous array-based ME/CFS studies
Inferred Conclusions
DNA methylation patterns systematically differ between ME/CFS patients and healthy controls, affecting genes related to metabolism, immunity, and neurological function
The overlapping results with array-based studies suggest robust epigenetic signatures associated with ME/CFS across different methodologies
Disrupted neurological pathophysiology, as reflected in altered neurotransmitter and neuropeptide pathways, appears to be a key feature of ME/CFS at the epigenetic level
Remaining Questions
Do these methylation changes occur before symptom onset, or are they consequences of having ME/CFS?
Which specific methylation changes are most important for causing or maintaining ME/CFS symptoms?
What This Study Does Not Prove
This study cannot establish whether the methylation changes cause ME/CFS symptoms or result from the illness and stress it causes. It does not prove that correcting these methylation patterns would improve symptoms, nor does it identify which specific methylation changes are most important for disease mechanisms. The small sample size also means these findings require validation in larger, independent cohorts.