Researchers at the University of Pennsylvania's School of Veterinary Medicine (Penn Vet), in collaboration with the University of Padova in Italy, have identified a novel genetic mutation linked to progressive retinal atrophy (PRA) in Labrador Retrievers (Stull, 2025). This discovery has significant implications for veterinary professionals, particularly those involved in ophthalmology and breeding programmes.

Understanding Progressive Retinal Atrophy (PRA)

PRA encompasses a group of inherited retinal diseases that lead to the gradual degeneration of photoreceptor cells in the retina, ultimately resulting in blindness (Zangerl et al., 2006). It is one of the most common causes of inherited blindness in dogs, with various breeds exhibiting breed-specific genetic mutations responsible for the condition (Kijas et al., 2002).

The Discovery: GTPBP2 Gene Mutation

In the recent study, researchers examined three Labrador Retriever littermates exhibiting signs of PRA. Genetic analysis revealed a three-base pair deletion in the coding region of the GTPBP2 gene (Stull, 2025). This gene encodes a GTP-binding protein expressed in multiple tissues, including the canine retina. The deletion results in the loss of a highly conserved alanine residue, which is believed to affect the protein’s function and cellular localisation, potentially contributing to photoreceptor degeneration.

Interestingly, GTPBP2 mutations have previously been associated with neurological conditions in mice (Davisson et al., 2012), but this is the first time the gene has been linked to retinal disease in dogs, indicating a novel disease mechanism in veterinary medicine.

Implications for Veterinary Practice

This finding underscores the importance of genetic testing in breeding programmes, especially for breeds predisposed to inherited retinal diseases. By identifying carriers of the GTPBP2 mutation, breeders can make informed decisions to reduce the prevalence of PRA in future generations.

For veterinary practitioners, this discovery highlights the need for awareness of emerging genetic mutations that may not be covered by existing diagnostic panels. Incorporating comprehensive genetic screening into routine health checks for breeds at risk can aid in early detection and management of PRA.

Future Directions

The identification of the GTPBP2 mutation opens avenues for further research into targeted therapies and interventions for PRA. Understanding the molecular mechanisms underlying this mutation may contribute to the development of gene therapies aimed at halting or reversing retinal degeneration in affected dogs.

Moreover, these findings could have translational value, providing insights into similar genetic mechanisms in human retinal diseases.

Conclusion

The discovery of a new genetic cause of blindness in dogs emphasises the dynamic nature of veterinary genetics and the continuous need for research and adaptation in clinical practices. Veterinary professionals should stay informed about such developments to provide optimal care and guidance to breeders and pet owners.

References

• Davisson, M. T., Schmidt, C., Reeves, R. H., Irving, N. G., Akeson, E. C., Harris, B. S., & Bronson, R. T. (2012). Genetic characterization of the Gtpbp2 mutation associated with neurodegeneration in mice. BMC Neuroscience, 13(1), 23. https://doi.org/10.1186/1471-2202-13-23

• Kijas, J. W., Cideciyan, A. V., Aleman, T. S., Pianta, M. J., Pearce-Kelling, S. E., Miller, B. J., ... & Acland, G. M. (2002). Naturally occurring rhodopsin mutation in the dog causes retinal dysfunction and degeneration mimicking human dominant retinitis pigmentosa. Proceedings of the National Academy of Sciences, 99(9), 6328–6333. https://doi.org/10.1073/pnas.082714999

• Stull, D. (2025, March 20). New genetic cause of blindness in dogs. Penn Today. Retrieved from https://penntoday.upenn.edu/news/penn-vet-new-genetic-cause-blindness-dogs

• Zangerl, B., Goldstein, O., Philp, A. R., Lindauer, S. J., Pearce-Kelling, S. E., Mullins, R. F., ... & Acland, G. M. (2006). Identical mutation in a novel retinal gene causes progressive rod–cone degeneration in dogs and retinitis pigmentosa in humans. Genomics, 88(5), 551–563. https://doi.org/10.1016/j.ygeno.2006.07.004​