GWAS-identified COVID-19 severity variants mapped to enhancer activity in lung cells

Researchers including Giovanna Weykopf, Wendy A. Bickmore, Simon C. Biddie, and Elias T. Friman have published a study in PLOS Genetics examining how common genetic variants in non-coding genomic regions influence risk of severe COVID-19. The majority of loci identified by genome-wide association studies (GWAS) for COVID-19 outcomes fall outside protein-coding sequences, making functional interpretation challenging. This work addresses that gap by deploying enhancer reporter assays in lung-relevant cell types to test whether risk variants alter gene regulatory activity.

The authors identified a subset of GWAS-nominated variants that modulate enhancer reporter activity, providing evidence that these non-coding changes act through transcriptional regulation in disease-relevant tissue. The approach is broadly applicable: by focusing functional experiments on cells and tissues implicated in the disease phenotype — in this case lung cells — it increases the prior probability that observed regulatory effects are mechanistically relevant.

The study contributes to the wider challenge of moving from statistical association to biological mechanism in complex disease genetics. Identifying which non-coding variants alter gene expression in the relevant cell type is a prerequisite for understanding disease aetiology and, in the longer term, for designing interventions. The work joins a substantial post-pandemic literature using COVID-19 GWAS as a tractable model for dissecting non-coding variant function.