# AAV gene therapy

AAV gene therapy uses a re-engineered virus (adeno-associated virus, AAV) to deliver a working gene into your tissues. The cargo is a 'transgene cassette': usually a promoter, a coding sequence, and a poly-A signal. Different AAV 'serotypes' home to different tissues (AAV9 for brain and muscle, AAV8 for liver, AAV2 for the retina), set by how their shell binds cell receptors. There is a size limit, though: the AAV can only pack about 4.7 kb, which restricts which genes fit in one construct. The biggest hurdle is your immune system. Pre-existing antibodies and T-cell responses to the viral shell can clear the therapy, and some trials have needed plasmapheresis or strong immunosuppression to avoid that (and liver toxicity). In longevity-relevant animal work, AAV vectors have delivered Klotho, TERT, follistatin, and FGF21, with functional improvements. But no anti-aging AAV product is approved, and all human longevity uses are experimental or compassionate-use.

## Sources

- Wang D, Tai PWL, Gao G. (2019). Adeno-associated virus vector as a platform for gene therapy delivery. Nature Reviews Drug Discovery. https://doi.org/10.1038/s41573-019-0012-9
- Duan D, Goemans N, Takeda S, Mercuri E, Aartsma-Rus A. (2021). Duchenne muscular dystrophy. Nature Reviews Disease Primers. https://doi.org/10.1038/s41572-021-00248-3

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_Canonical: https://longevity-switzerland.com/en/glossary/aav-gene-therapy · Part of Longevity Cities · Updated 2026-06-22_