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Osteochondrodysplasia in Scottish Fold cats
Roni Ertzman Koret School of Veterinary Medicine, Faculty of Agricultural, Food and Environmental Sciences, The Hebrew University of Jerusalem.
Mentor: Zahi Aizanberg, DVM Koret School of Veterinary Medicine, Faculty of Agricultural, Food and Environmental Sciences, The Hebrew University of Jerusalem.
The development of the Scottish fold cats breed began in Scotland in 1961 when a spontaneous mutation in a female British shorthair resulted in forward-folded ears, which is the defining feature of the breed. There was no mention of any skeletal deformities until 1971 when progressive bony abnormalities and a crippling lameness were recognized. Scottish fold osteochondrodysplasia is a hereditary disease affecting bone growth as well as formation of articular cartilage. It is inherited as a simple autosomal dominant trait (the defected allele is designated Fd). Both heterozygous and homozygous for the Fd allele can suffer from clinical disease. It leads to progressive skeletal deformities at the distal parts of the legs and the tail. Lesions are evident radiographically in kittens aged 7 weeks. The metaphyses of metatarsal and metacarpal bones are distorted with widened physes. After the age of 6 months, exostoses on the plantar surface of metaphyses bones and progressive ankylosing arthropathy are evident. Similar, but less marked changes are evident in phalanges. This results in abnormal shape of this bones and shortening of distal limbs. Joint lesions progress until the cats are unable to walk. The current treatment of affected cats, which usually includes glycosaminoglycans and NSAIDS, is unsatisfactory because the disease is relentlessly progressive and in severe cases it doesn’t reduce lameness and accompanying pain. Therefore, some new treatments were performed on affected cats. In one case, palliative irradiation therapy was performed on both hindlegs in order to decrease the new bone formation and ankylosing arthropathy. After six radiotherapy sessions (over two weeks) the cat had no side effects. Twenty-eight months after therapy there were no sings of further bone proliferation on radiographs of both hindlegs and the exostoses had smooth surface. The cat had no lameness problems. In another case bilateral ostectomies and pantarsal arthrodeses were performed on both hindlegs. The cat remained improved and had no lameness signs or recurrence of exostoses 96 weeks after the surgery. As for now, and as long as Scottish fold breed exists, efficient treatment must be found for the affected cats. The most suitable solution for this disease would be to abandon using fold-eared cats in breeding.
References: 1. Hubler, M., Volkert, M., Kaser-Hotz, B. and Arnold, S.: Palliative irradiation of Scottish fold osteochondrodysplasia. Veterinary radiology & ultrasound. 45 (6): 582-585, 2004. 2. Malik, R., Allan, G. S., Howlett, C. R., Thompson, D. E., James, G., Mcwirter, C., and Kendall, K.: Osteochondrodysplasia in Scottish fold cats. Australian veterinary journal. 77 (2): 85-92, 1999. 3. Mathews, K. G., Koblik, P. D., Knoeckel, M. J., Pool, R. R. and Fyfe, J. C.: Resolution of lameness associated with Scottish fold osteodystrophy following bilateral ostectomies and pantarsal arthrodeses: a case report. Journal of the American Animal Hospital association. 31: 280-288, 1995. 4. Partington, B. P., Williams, J. F., Pechman, R. D. and Beach, R. T. What is your diagnosis? Scottish fold osteodystrophy. Journal of American veterinary medicine association. 209: 1235-1236, 1996. |
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