Gene Therapy for Common Polygenic Diseases Remains Fundamentally Unsolved

Nearly all approved gene therapies treat single-gene diseases. But the diseases that kill the most people — heart disease, diabetes, Alzheimer's, most cancers — involve dozens to hundreds of genes. We don't know how to safely edit multiple genes simultaneously, and multiplexed editing exponentially increases off-target risks.

GWAS identifies hundreds of variants per common disease, each with tiny effect sizes (OR 1.01-1.2). Multiplexed editing increases translocation risk between cut sites. Verve Therapeutics' PCSK9 base editing for cardiovascular disease is the only real attempt at in vivo editing for a common disease — exploiting a rare case where a single gene strongly modulates an entire risk pathway. Epigenetic editing (CRISPRa/CRISPRi) could modulate multiple genes without permanent cuts but lacks durability and efficient delivery.

Why It Matters

Heart disease: 700,000 US deaths/year. Type 2 diabetes: 37M Americans. Alzheimer's: 6.2M. Monogenic diseases collectively affect 3.5-5.9% of population; polygenic diseases affect >50%. If gene therapy stays monogenic, it remains niche.

Startup Approach

Use human genetics to identify monogenic 'leverage points' within polygenic pathways (like PCSK9 for CVD). Mine large biobanks for protective loss-of-function variants that dramatically reduce common disease risk. Develop single-gene editing therapies mimicking these natural protective mutations.

NIH Funding

NHGRI genomic medicine programs fund GWAS-to-therapy translation. NHLBI TOPMed supports polygenic risk research. Common Fund SCGE discussed polygenic applications in forward strategy.

Who's Working On It

Verve Therapeutics (PCSK9/ANGPTL3 editing for CVD), Tune Therapeutics (CRISPRoff epigenetic silencing), Epic Bio/Epicrispr (epigenetic modulation), Jonathan Weissman lab (MIT, CRISPRi screening)