Atrophie progressive de la rétine du Border Collie : étude rétrospective (1996-2012)

From 1996 to 2012, systematic ocular examinations performed on 1358 Border Collies (760 females and 598 males, aged from 1 to 13 years) using indirect ophthalmoscopy, highlighted focal, multifocal or generalized lesions of retinal atrophy in 113 dogs (98 males and 15 females). The affected individuals were on average 4-year-old. Some dogs underwent several examinations, at least once a year, and revealed progressive lesions. The electroretinography performed in 15 dogs showed a decrease of the b wave amplitude proportional in the number and in the larger the surface of the lesions of the fundus. In some cases, this decrease was associated to an increase of the latency of the peak of the b wave. The fluorescein angiography performed in 10 dogs revealed a latency of the arterial phase exclusively in the individuals affected with coalescent multifocal or diffuse lesions. The analysis of these angiographs allowed the conclusion of retinal epithelial lesions, confirmed by histologic examinations of retinas. The study of a pedigree of 375 dogs highlighted an X-linked mode of inheritance. This mode of inheritance is confirmed by the current pedigree that contains more than 700 individuals with a majority of males being affected. Although the mutation responsible for this form of X-linked PRA in the Border Collie has not been yet identified, the understanding of the mode of inheritance and the information given by the French Border Collie breed Kennel Club enable to decrease the frequency from the affected dogs from 20% in 2001 to 8% in 2012. The research of the genetic cause of this disease is still ongoing.