325: cis-pcQTL mapping reveals allelic proxitropy across neighboring human genes

Lawrence et al., The American Journal of Human Genetics - Using a cis-principal-component (pcQTL) approach in human GTEx tissues, the authors uncover novel multi-gene regulatory variants and 33% more GWAS colocalizations than single-gene eQTLs. Key terms: pcQTL, allelic proxitropy, GTEx, colocalization, HOXB. Study Highlights:The study analyzes 13 human GTEx tissues and identifies clusters of co-expressed neighboring genes, then applies PCA to cluster expression and maps cis-principal-component QTLs (pcQTLs). pcQTL discovery and fine-mapping used SuSiE and TensorQTL permutation-based FDR to identify an average of ~1,396 pcQTLs per tissue, ~27% of which were not found by single-gene eQTL mapping. pcQTLs tend to represent smaller effects distributed across multiple genes in a cluster and often colocalize with GWAS hits missed by single-gene methods. Functionally, pcQTLs increased GWAS colocalizations by 33%, highlighting multi-gene regulatory proxitropy as a source of complex-trait-associated variation. Conclusion:Cis-multi-gene pcQTL mapping uncovers novel regulatory loci and increases GWAS colocalizations compared with single-gene analyses, demonstrating that multi-gene approaches improve detection and interpretation of complex-trait-associated variants. Music:Enjoy the music based on this article at the end of the episode. Article title:Focus on single-gene effects limits discovery and interpretation of complex-trait-associated variants First author:Lawrence Journal:The American Journal of Human Genetics DOI:10.1016/j.ajhg.2026.02.022 Reference:Lawrence, K.A., Gjorgjieva, T., Nachun, D., and Montgomery, S.B. (2026). Focus on single-gene effects limits discovery and interpretation of complex-trait-associated variants. The American Journal of Human Genetics 113, 1–10. https://doi.org/10.1016/j.ajhg.2026.02.022 License:This episode is based on an open-access article published under the Creative Commons Attribution 4.0 International License (CC BY 4.0) - https://creativecommons.org/licenses/by/4.0/ Support:Base by Base – Stripe donations: https://donate.stripe.com/7sY4gz71B2sN3RWac5gEg00 Official website https://basebybase.com On PaperCast Base by Base you’ll discover the latest in genomics, functional genomics, structural genomics, and proteomics. Episode link: https://basebybase.com/episodes/cis-pcqtl-allelic-proxitropy-gtex QC:This episode was checked against the original article PDF and publication metadata for the episode release published on 2026-03-24. QC Scope:- article metadata and core scientific claims from the narration- excludes analogies, intro/outro, and music- transcript coverage: Audited the transcript sections presenting the conceptual shift to neighborhood gene regulation (allelic proxytropy), the cis-pcQTL (pcQTL) methodology, GTEx tissue clustering, key quantitative results (novel pcQTLs, clusters, colocalizations), and concrete examples (HOXB cluster, IL-18 receptor genes), plus discussion- transcript topics: Conceptual shift to gene neighborhoods and allelic proxytropy; cis-pcQTL (pcQTL) methodology and PCA-based signal extraction; GTEx tissue clusters and gene-neighborhood calling; pcQTL discovery statistics (clusters, pcQTLs per tissue, novel signals); pcQTLs and GWAS colocalizations; HOXB cluster example (HOXB3 vs HOXB4) and PC4 QC Summary:- factual score: 10/10- metadata score: 10/10- supported core claims: 6- claims flagged for review: 0- metadata checks passed: 4- metadata issues found: 0 Metadata Audited:- article_doi- article_title- article_journal- license Factual Items Audited:- pcQTLs reveal novel multi-gene regulatory variants missed by single-gene eQTLs- average pcQTLs per tissue is 1,396-... Chapters (00:00:00) - Deep Dive: The genome's interconnected networks(00:05:27) - The Shared Signal of Genomic Science(00:11:15) - Single gene mapping fails to explain complex traits(00:18:13) - Understanding the genetics of human diseases(00:20:39) - Beyond one gene