L. Lima; M.H. Tramontin; M. Bacellar; F. Montiani-Ferreira
Retinal dysplasia (RD) is a disease that affects a wide variety of dog breeds and is characterized by the presence of retinal folds. These folds can progress to partial or total retinal detachment and blindness. There may be complicating factors and nonspecific clinical signs such as hyphema that may require ancillary tests such as ultrasound and even histopathologic evaluation to confirm the diagnosis. Retinal dysplasia has multiple etiologies, including viral infections, toxins, nutritional deficiencies, intrauterine trauma, radiation exposure and genetic mutations. Heritable retinal dysplasia has been described in many dog breeds, but not yet in the Pit Bull Terrier. A condition called cone rod dystrophy, however, has been documented already. RD is untreatable, thus, the recommended procedure is early ophthalmoscopic evaluation and exclusion of the affected or suspected individuals from breeding programs. The objective of this investigation is to document an inherited form of RD observed in Pit Bull Terriers. All dogs belonged to a Pit Bull Terrier breeder. A. cross between an affected female and an affected male produced 7 affected puppies. Clinical signs including partial or total retinal detachment, poor vision and presence of retinal folds were all present at eyelid opening in all affected puppies. The ophthalmic evaluation of these 2 affected adult dogs as well as the offspring revealed that most animals showed partial retinal detachment along with multifocal retinal folds and loss of vision acuity. Some affected animals showed total retinal detachment and blindness. Funduscopy and ultrasound evaluation revealed that two animals had bilateral retinal detachment and blindness, two animals had partial retinal detachment in one eye with retinal folds in both eyes, and, lastly five animals had multifocal retinal folds retaining fair visual acuity in the latter two cases. This work describes for the first time a form of retinal dysplasia in Pit Bull Terriers and provides important clinical data about this genetic condition. This form of RD certainly needs to be further investigated, mainly concerning the exact mode of inheritance and gene that is involved. Additionally, it serves to alert owners and breeders about the importance of early ophthalmic evaluation of pure breed dogs, to remove affected alleles from the gene pool.