Background
Essential tremor (ET), the most common movement disorder, affects ~4% of adults over 40, yet its genetic and neurobiological basis remains unclear.
Methods
We conducted a genome-wide association meta-analysis including 20,268 ET cases and 723,761 neurologically healthy controls of European ancestry (Million Veteran Program, 23andMe, All of Us), testing ~22 million quality-controlled SNPs. SNP heritability was estimated using LD score regression. We performed genetic correlation analyses across 2,800+ traits (FDR < 0.05), integrated transcriptomic data via S-PrediXcan/S-MultiXcan, fine-mapped genes with FOCUS, assessed colocalization with GTEx v8 brain eQTLs, and examined spatial/cellular enrichment using gsMap. Polygenic risk scores (PRS) were evaluated in UK Biobank (EUR) and All of Us (AFR/AMR).
Results
We identified 50 independent genome-wide significant loci, 47 novel, with SNP-based heritability of 18.5% (liability scale). ET showed positive genetic correlations with Parkinson’s disease, restless legs syndrome, and neuroticism, and negative correlations with ventral diencephalon and cerebellar volumes. Transcriptome-wide and fine-mapping analyses highlighted BACE2 and S100A13 as top candidates, with colocalization supporting BACE2, S100A13, PCDH9, and HARS as likely causal. Cell-type enrichment implicated excitatory cortical and hippocampal neurons, astrocytes, and microglia, aligning with a cerebellar–cortical circuit model. PRS predicted ET risk in European ancestry (OR = 2.15, AUC = 0.69), with moderate performance in admixed American (OR = 1.99, AUC = 0.67) and limited in African ancestry (OR = 1.17, AUC = 0.52).
Interpretation
This largest ET GWAS expands the genetic landscape and links risk to cerebellar-diencephalic structure and excitatory neuron programs, implicating glial contributions. Convergent evidence nominates BACE2, S100A13, HARS, and PCDH9 as actionable targets and supports PRS-based risk prediction in European populations. Broader ancestral representation remains essential for equitable genomic medicine.