MRAgent - Automated Mendelian Randomization Analysis Agent

Description

MRAgent is an intelligent agent that automates the entire process of Mendelian randomization analysis for causal discovery in biomedical research. It:

1. Knowledge Discovery Mode (KD): Given a disease (outcome), automatically scans PubMed literature to discover potential modifiable exposure (risk factor) that have correlation but no established causal inference, then performs comprehensive Mendelian randomization analysis using OpenGWAS data to identify novel causal relationships.

1. Causal Validation Mode (CV): Directly test whether a user-specified exposure (e.g., "body mass index") has a causal effect on a specific outcome (e.g., "type 2 diabetes") using two-sample Mendelian randomization.

MRAgent handles all steps automatically:

• PubMed literature crawling
• LLM-based extraction of candidate exposure-outcome pairs
• Check for existing MR studies via PubMed search
• Optional STROBE-MR quality assessment of existing studies
• UMLS medical synonym expansion
• OpenGWAS database query for GWAS summary statistics
• LLM selection of most appropriate GWAS datasets
• Multiple MR methods: Inverse variance weighted, MR-Egger, weighted median, etc.
• Heterogeneity analysis and pleiotropy sensitivity testing
• MRlap correction for sample overlap
• Automatic generation of publication-ready PDF reports with LLM-written interpretation

Requirements

• Python packages (install via pip install -r {baseDir}/requirements.txt)
• R language (>= 4.3.4) with the following packages installed:
• TwoSampleMR - core Mendelian randomization
• ieugwasr - OpenGWAS interface
• vcfR - required for MRlap (optional)
• MRlap - sample overlap correction (optional)
• jsonlite - JSON processing (required for MRlap)
• OPENAI_API_KEY environment variable must be set (OpenAI API key)
• OPENGWAS_JWT environment variable (optional, for OpenGWAS access token)

Usage

Knowledge Discovery Mode (recommended for novel discoveries)

Discover novel causal relationships starting from a disease:

python {baseDir}/run_mragent.py --mode KD --outcome "back pain" --num-pubmed 100 --bidirectional

Discover novel causal relationships starting from an exposure:

(Currently the CLI implements KD starting from outcome; for exposure-based discovery use the Python API directly)

Causal Validation Mode

Validate a specific hypothesis: does exposure causally affect outcome?

python {baseDir}/run_mragent.py --mode CV --exposure "body mass index" --outcome "type 2 diabetes"

Common Options

Environment Variables

Output

MRAgent outputs a JSON summary to stdout with:

• success: boolean indicating success
• output_directory: directory containing all results
• discovered_pairs: number of candidate exposure-outcome pairs found
• selected_for_mr: number of pairs selected for MR analysis
• reports: list of paths to generated PDF files (Report.pdf, Introduction.pdf, Conclusion.pdf, etc.)

Example output:

{
  "success": true,
  "mode": "CV",
  "outcome": "back pain",
  "exposure": "osteoarthritis",
  "output_directory": "./output/osteoarthritis_back_pain_gpt-4o",
  "discovered_pairs": 1,
  "selected_for_mr": 1,
  "reports": [
    "./output/osteoarthritis_back_pain_gpt-4o/osteoarthritis_back_pain/Introduction.pdf",
    "./output/osteoarthritis_back_pain_gpt-4o/osteoarthritis_back_pain/osteoarthritis_back_pain/MR_ieu-a-2_ieu-a-1008/Report.pdf",
    "./output/osteoarthritis_back_pain_gpt-4o/osteoarthritis_back_pain/Conclusion.pdf"
  ]
}

Workflow Steps

When running all steps (default):

Notes

• This is a computationally intensive process. The full analysis can take tens of minutes to hours depending on the number of pairs.
• All intermediate results are saved as CSV files in the output directory, allowing manual editing and intervention between steps.
• MRAgent requires R to be installed with the necessary packages, because the actual MR analysis is performed by R's TwoSampleMR package.