Preprint reports long-term retinal preservation with AAV8-PEX1 gene therapy in Zellweger spectrum disorder mouse model
A bioRxiv preprint describes sustained preservation of retinal integrity and function following AAV8-delivered PEX1 gene therapy in a murine model of Zellweger spectrum disorder.
A preprint posted to bioRxiv (14 May 2026) presents data from a long-term evaluation of AAV8-mediated gene therapy targeting the PEX1 gene in a mouse model of Zellweger spectrum disorder (ZSD), a peroxisome biogenesis disorder caused by pathogenic variants in PEX genes.
ZSD encompasses a clinical spectrum from the severe Zellweger syndrome — typically lethal in infancy — to milder forms including neonatal adrenoleukodystrophy and infantile Refsum disease. Retinal degeneration is a consistent feature across the spectrum, contributing to progressive vision loss. There are currently no proven disease-modifying treatments for ZSD.
The preprint reports that a single subretinal injection of an AAV8 vector carrying a functional PEX1 transgene preserved retinal structure and function over an extended period in the murine model, with treated eyes showing significantly less photoreceptor degeneration than controls. The authors suggest that localised restoration of peroxisome function within the retina is sufficient to mitigate retinal degeneration in this model.
This is an early-stage preprint and has not been peer-reviewed. The findings are of interest to researchers in inherited retinal diseases, peroxisome biology, and ocular gene therapy. For genetic counsellors supporting families with ZSD, the existence of an active gene therapy research programme is relevant background context, though no clinical application is currently available.
Plain-language version
For patients, families, and general readers. Educational only — not medical advice.
Zellweger spectrum disorder (ZSD) is a rare genetic condition affecting a part of cells called peroxisomes, which are important for breaking down certain fats and other molecules. One of the consistent effects of ZSD is gradual loss of vision. A new piece of research — not yet reviewed by other scientists — reports that delivering a working copy of the faulty PEX1 gene directly into the eyes of mice with a ZSD-like condition helped preserve their retinas over a long period. This is laboratory research and does not mean a treatment is available for people. However, it is an encouraging step for researchers working towards future therapies. This is an educational summary, not medical advice. If anything here raises questions for you, please speak with your GP or a clinical professional.
Sources
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Primary sourcePreprint bioRxiv (Cold Spring Harbor Laboratory) · 2026-05-14Clinically relevant AAV8-PEX1 gene therapy preserves retinal integrity and function long-term in a murine model of Zellweger spectrum disorder