A cross-tissue transcriptome-wide association study identifies WDPCP as a potential susceptibility gene for coronary atherosclerosis.

Background: Coronary atherosclerosis (CAS) is a complex chronic inflammatory disease with significant genetic and environmental contributions. While genome-wide association studies (GWAS) have pinpointed many risk loci, over 75 % are in non-coding regions, complicating functional analysis and understanding gene-disease mechanisms.

Methods: We conducted a cross-tissue transcriptome-wide association study (TWAS) using data from the GWAS Catalog (16,041 cases, 440,307 controls) and the Genotype-Tissue Expression (GTEx) v8 eQTL dataset. Initially, we used the Unified Test for Molecular Signatures (UTMOST) for analysis, followed by validation with Functional Summary-based Imputation (FUSION) and conditional and joint (COJO) analyses. Candidate genes were further refined using Multi-marker Analysis of Genomic Annotation (MAGMA). Causal relationships were assessed through Summary Data-Based Mendelian Randomization (SMR), colocalization analysis (COLOC), and Mendelian Randomization (MR). GeneMANIA was used to identify interacting genes, and Phenome-Wide Association Study (PheWAS) was employed to enhance the results.

Results: UTMOST identified 33 susceptibility genes for CAS. Out of these, 17 met stringent criteria in both UTMOST and FUSION analyses. Combining results from UTMOST, FUSION, and MAGMA, we identified four critical candidate genes. WDPCP was the only gene to pass SMR, COLOC, and MR analyses, confirming its causal role in CAS. GeneMANIA revealed additional interacting genes, and PheWAS validated WDPCP's role as a susceptibility gene.

Conclusion: WDPCP is a potential novel susceptibility gene for CAS, influencing endothelial function, lipid metabolism, and coronary artery development. This study extends GWAS findings, highlighting WDPCP's potential as a therapeutic target and its consistent expression across different tissues. Further validation studies are warranted.