Novel Genetic Variant Linked to Retinal Atrophy Identified in Labrador Retrievers

Researchers from the University of Pennsylvania and the University of Padova have identified a novel genetic variant associated with progressive retinal atrophy in three Labrador retrievers. The study, published in *Scientific Reports*, details the discovery of a 3-bp [three base pair] deletion in the coding region of *GTPBP2*, a gene encoding a G-protein expressed in the canine retina. This deletion leads to the loss of a conserved alanine. The affected dogs, identified through a service dog breeding foundation, exhibited only retinal degeneration and blindness. An analysis of 91 unaffected Labrador retrievers from the same kennel and 569 from the general U.S. population revealed 16 carriers of the variant, all from the original kennel, indicating its rarity. Mutations in *GTPBP2* in humans are associated with Jaberi-Elahi syndrome, characterized by neurologic and morphologic abnormalities. However, the canine variant appears less severe, affecting only the retina. Researchers suggest this difference may be due to the mutation's location on the protein, potentially impacting its cellular localization rather than its GTPase activity. This finding illustrates the flexibility of phenotypes in medical genetics.