E2 ModeratePreliminaryPEM unclearCase-ControlPeer-reviewedMachine draft
Convergent genomic studies identify association of GRIK2 and NPAS2 with chronic fatigue syndrome.
Smith, Alicia K, Fang, Hong, Whistler, Toni et al. · Neuropsychobiology · 2011 · DOI
Quick Summary
Researchers used a novel genetic screening approach to search for genes that might be involved in ME/CFS by comparing DNA variants and gene activity between people with ME/CFS and healthy controls. They identified two genes—GRIK2 and NPAS2—that showed both genetic differences and altered activity levels in people with ME/CFS. GRIK2 is involved in communication between nerve cells, while NPAS2 controls the body's internal clock, suggesting these biological systems may play a role in the condition.
Why It Matters
This is one of the first genome-wide efforts to systematically identify genetic associations in ME/CFS using an integrative approach. Implicating glutamatergic neurotransmission and circadian rhythm genes provides testable biological hypotheses that could explain some ME/CFS symptoms and guide development of targeted diagnostics or therapeutics.
Observed Findings
- Sixty-five SNPs were nominally associated with CFS at p<0.001
- 165 genes were differentially expressed (≥4-fold change; p≤0.05) in CFS peripheral blood mononuclear cells
- GRIK2 rs2247215 G allele was associated with CFS status (p=0.0005) with 10-fold decreased expression in CFS subjects (p=0.015)
- NPAS2 rs356653 T allele was associated with CFS status (p=0.0007) with 10-fold increased expression in CFS subjects (p=0.027)
- Two genes converged across both SNP and expression analyses despite evaluation of >116,000 SNPs and >20,000 genes
Inferred Conclusions
- Genes involved in glutamatergic neurotransmission and circadian rhythm regulation may contribute to CFS pathogenesis
- Convergent functional genomics is an effective strategy for candidate gene prioritization in complex diseases
- The identified variants warrant further investigation in independent CFS populations to confirm association and elucidate functional mechanisms
Remaining Questions
- Do GRIK2 and NPAS2 variants replicate in independent CFS cohorts, and what is their effect size in larger populations?
- What are the functional consequences of these variants—do they alter protein function, expression regulation, or both?
What This Study Does Not Prove
This study does not prove that GRIK2 or NPAS2 variants cause ME/CFS, only that they are statistically associated with the condition in this population. The findings require independent replication in larger cohorts before clinical application. Genetic association does not establish mechanism or treatment relevance.
Tags
Symptom:Fatigue
Biomarker:Gene ExpressionBlood Biomarker
Method Flag:Weak Case DefinitionSmall SampleExploratory Only
Metadata
- DOI
- 10.1159/000326692
- PMID
- 21912186
- Review status
- Machine draft
- Evidence level
- Single-study or moderate support from human research
- Last updated
- 8 April 2026
About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →
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