Inherited eye diseases are common in purebred animals, especially dogs. They affect the eye, and, because of breed/species-specific conformational standards, the affect the eye secondarily as a result of abnormal shape and/or conformation of the eyelids and other extraocular structures. Until recently, control was based on knowing the mode of inheritance, and eliminating from breeding all dogs that were affected or carriers of the disease. Because many of the disorders are inherited as autosomal recessive traits, control also resulted in elimination from breeding of dogs having a high probability of being carriers of these diseases.

Progress has recently been made in understanding the molecular bases of many of these diseases, particularly in dogs. We now know that many of the inherited retinal diseases are cause by defects (mutations) in genes known to affect retinal function. This has resulted in the availability of many DNA-based tests which are specific for the genetic defect, and, for recessive diseases, allow the use of affected or carrier animals in breeding programs as long as they are used for breeding to genetically normal animals. This prevents the likelihood of producing any affected animals, and, at the same time, maintaining the genetic diversity of these breeds, thus preventing the occurrence of other inherited diseases at a high prevalence rate.

In this seminar, we will review the different major inherited eye diseases in dogs and, where known, in cats. As well, we will discuss the application of new DNA testing technologies to help identify affected and carrier animals, and reduce the frequency of the mutation in the population while, at the same time, maintaining the genetic diversity of the breeds.