There’s a rare, inherited sight condition, involving faulty copies of the CaBP4 gene, that causes poor vision from childhood. The protein made by the gene is crucial for chemical signaling in the retina.It’s also something that can affect dogs – and in treating pooches, researchers have discovered a therapy approach that promises to be transformative.In a study published in Molecular Therapy Advances, researchers led by a team from Michigan State University in the US report that a single-dose gene therapy treatment not only stopped blindness from progressing, it physically repaired damaged connections.It raises the tantalizing prospect of treatments that can repair nerve cells in mammals, something which had previously been thought by many to be impossible.”We were able to show three independent structural changes supporting plasticity in the adult retina,” says veterinary ophthalmologist Billie Beckwith-Cohen, from Michigan State University. “Not only were new components added, but pre-existing abnormalities were repaired.”Having identified the CaBP4 gene as being responsible for vision loss in a group of whippet dogs, the researchers injected the retinas of the animals with a harmless virus carrying a working copy of the gene.
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The treatment substantially improved vision in the canines, especially in dim light – which is where the CaBP4 protein deficiency makes the most difference.What’s more, treated regions of the retina degraded less, and the outer plexiform layer (OPL) that holds crucial visual connectors expanded significantly, as did the synaptic ribbons inside the eye’s light-sensing cells.The growth of the OPL and the synaptic ribbons is stunted when the CaBP4 gene isn’t working properly, which the researchers compare to errors in a building plan.”One can essentially discuss the mutations in the retinal gene as a typo in a blueprint that makes the instructions incomprehensible to the system, resulting in a faulty design and subsequent vision loss,” says Beckwith-Cohen. “Our therapy essentially provides new instructions for the misspelled segment, like an editor.”A dog retina scan showing repaired nerve connections two years after treatment. (Beckwith-Cohen et al., Mol. Ther. Adv., 2026)The study is the result of a decade of research into these eye conditions, and while it remains to be seen whether the same approach would work in human beings, the team is confident it would translate.”Our results show that gene therapy is not only capable of restoring retinal function but is also able to establish a nearly normal anatomical arrangement in the OPL of the retina,” write the researchers in their published paper.”This recovery involves expansion of a layer that did not form normally during retinal development along with maturation of synaptic features such as ribbon elongation, supporting the lasting blueprint of the retinal neural network through adulthood.”Although the CaBP4 gene condition is rare both in people and in dogs, the researchers suggest that the findings here could lead to other methods for repairing damaged neural networks and treating a wider range of conditions.Even after significantly stunted growth in the eye and subsequent damage to nerve cell connections, there was evidence of nerve cells being rewired. The benefits lasted too, with follow-up periods of up to three years in this study.Now we know that new neural connections can be made in the retina; there are plenty more avenues of related research to explore, including the role of calcium signaling (which CaBP4 handles) in handling cell communication in the eye.We’ve seen some encouraging steps forward in treatments to restore vision in recent years, including activating dormant cells in the eye and protecting photoreceptors, and this is another to add to the list.”Our findings exhibit restoration of visual function in dogs with severe electrophysiologic and synaptic dysfunction,” write the researchers.”We establish that the OPL of the retina has profound plasticity and that the synaptic ribbons can mature and elongate following gene augmentation therapy well into adulthood.”
The research has been published in Molecular Therapy Advances.This article was fact-checked by Fiona MacDonald and edited by Fiona MacDonald. While we pride ourselves on our process, we are only human. If you spot a mistake, please let us know.