Source: Canine Genetics and Epidemiology
Author: Cathryn S Mellersh – email@example.com
Progressive retinal atrophy (PRA) is a group of inherited eye disorders that occur in many different dog breeds. Each form of PRA shows a simple pattern of mendelian inheritance, and is due to a mutation in one gene. However, over 20 different PRA-causing mutations have now been identified in a number of different genes. Some breeds, including Golden Retrievers (GR), may have more than one genetic form of PRA.
Canine PRA is considered to be the equivalent of Retinitis Pigmentosa (RP), which is a group of inherited human eye diseases.
This paper has identified a gene called TTC8 that is associated with PRA in GR. Interestingly the human TTC8 gene has previously been associated with RP. There is a one DNA base deletion in the gene which results in a shorter than normal protein to be made by the faulty version of the gene.
All the cases in this study were genetically screened for the other two known mutations for PRA in GR, and none were homozygous (two copies) for either of those mutations.
The gene was first identified by whole genome scanning 10 cases and 16 controls. A single mutation was identified in the gene by DNA sequencing, and it was confirmed by screening a larger number of dogs. Read more….