Methods

TWAS Pipeline

GWAS Summary Statistics → FUSION TWAS → Gene-level Associations
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                     eQTL Weights (GTEx v8 Skeletal Muscle, n=803)

GWAS Phenotypes (28 total)

• Strength (5): grip strength, walking pace, muscle weakness, grip CSA
• Mass (15): whole body FFM, appendicular lean mass, leg/arm/trunk FFM, etc.
• LeanMuscle (2): anterior/posterior thigh fat infiltration (direction reversed)
• Youth (1): telomere length (direction reversed)
• Resilience (5): muscular dystrophy, other myopathies, myopathy phecode, creatine kinase (direction reversed)

Direction Definition

• direction = +1: High expression → Healthy
• direction = -1: High expression → Unhealthy (reversed in scoring)

Data Sources

Source	Samples	Description
GTEx	803	Healthy controls (autopsy)
GEO	668	Multiple myopathy studies
Myofin (Helsinki)	154	Titinopathy, IBM cohort
HuashanMuscle	97	DM1, LGMD Chinese cohort