Genotypic and allelic frequencies of progressive rod‐cone degeneration and other main variants associated with progressive retinal atrophy in Italian dogs

Background: Progressive retinal atrophy (PRA) is a group of canine inherited retinal disorders affecting up to 100 breeds. Genetic tests are available. The aim of this study was to retrospectively evaluate the genetic variants associated with PRA among dogs residing in Italy. Methods: Genetic data of 20 variants associated with different forms of PRA were col- lected through DNA tests over a 10-year period for several dog breeds in the Italian canine population. Allelic and genotypic frequencies were calculated. Results: A total of 1467 DNA tests were conducted for 1180 dogs. Progressive rod-cone degeneration (PRCD) was the most tested form of PRA, with 58.15% (n = 853) of the DNA tests. Among the widespread breeds in Italy, Labrador retrievers and toy poodles showed a prevalence of heterozygous carriers higher than 15%. Among the others, 175 DNA tests for golden retrievers (GR) showed a prevalence of heterozygous carriers of 13.04% (n = 12) for GR-PRA1 and 8.43% (n = 7) for GR-PRA2. The zwergschnauzer breed was tested for the type B and/or the type B1 forms of PRA with 25.32% (n = 20) heterozygous carriers and 0%, respectively. Conclusion: The study offers an overview of the prevalence of PRCD and other PRA forms within some of the most popular breeds in Italy.