02952: Genetics of X-linked Progressive Retinal Atrophy in Greyhounds

One Health: Yes

Abstract

Progressive retinal atrophy (PRA) is a group of heritable retinal diseases characterized by retinal degeneration in both eyes which progresses to blindness and for which no treatment exists. Most forms of PRA occur via an autosomal recessive form of inheritance with only a few X-linked PRAs reported due to degeneration of areas of the retina that express the defective X chromosome. In humans, X-linked PRA causes particularly severe disease, thus canine models of this condition would be particularly beneficial for identifying novel genetic causes and developing new therapies for both species. The research team has identified 72 racing Greyhounds with vision impairment typically initially observed at 1.5-4 years of age and confirmed PRA in 46 dogs. Of the 72 Greyhounds, 69 are male which strongly implicates an X-linked pattern of inheritance. Importantly, this disease appears widespread through selection of daughters of a popular sire. In dogs, two types of X-linked PRAs have been described with mutations in the gene RPGR and sequencing of the exon containing these mutations in one PRA-affected Greyhound determined that they were not present. Investigators have also identified three putative carrier females with PRA, although the phenotype is less severe. This preliminary data suggests that a new X-linked PRA likely exists in racing Greyhounds with the potential to dramatically impact the well-being and adoptability of these visually impaired dogs. Furthermore, AKC registered Greyhounds may also be affected as the frequency of carriers is currently unknown. This study aims to identify the causal mutation, develop a genetic test, define the phenotype in carrier females, and determine the prevalence of the causal variant in Greyhounds.

Publication(s)

None at this time.