1. Kennel Club Genetics Centre, Animal Health Trust, Newmarket, Suffolk, CB8 7UU, United Kingdom
2. College of Veterinary Medicine, University of Missouri, Columbia, Missouri 65211
3. Department of Pathology, University of California, San Diego, La Jolla, California 92093-0709
4. Department of Neurology, Small Animal Clinic, Animal Health Trust, Newmarket, Suffolk, CB8 7UU, United Kingdom
5. The School of Veterinary Medicine, University of Glasgow, G61 1QH, United Kingdom
6. Department of Clinical Science and Services, Royal Veterinary College, University of London, Hatfield, Hertfordshire, AL9 7TA, United Kingdom