PROGRESSIVE RETINAL ATROPHY IN THE TIBETAN SPANIEL IN NORWAY AND SWEDEN

Progressive retinal atrophy of the late onset type was diagnosed in 51 Tibetan spaniels in Norway and Sweden. At the time of diagnosis they were between three and seven years old; however, early ophthalmoscopic changes caused by the thinning of the retina could sometimes be diffi cult to observe because of the partial or total lack of the tapetum in many of the dogs. The disease developed rapidly, approximately one ye ar passing from the initial clinical signs of night blindness to compl ete loss of vision. Twenty-four male and 27 female dogs were affected. All the affected dogs were interrelated and could be traced back to c ommon English ancestors. On the basis of pedigree studies, an autosoma l recessive mode of inheritance is postulated. Information on 15 diagn osed cases of the condition in other countries shows that the disease may be considered a worldwide problem in the Tibetan spaniel.