Collie eye anomaly in the United Kingdom

Abstract

Approximately 2500 rough collies, smooth collies and Shetland sheepdogs were examined during a three year period in an attempt to establish the incidence of collie eye anomaly in the United Kingdom and to produce data on the hereditability of the disease. The overall incidence in the two collie breeds was approximately 64 per cent, but the disease was seen with slightly more frequency in the Shetland sheepdog, 72 per cent of the dogs examined being affected. Pedigree analysis and test mating has confirmed the opinion held in the USA that the disease is inherited as an autosomal recessive trait. In this report the pleomorphism of the disease in these three breeds is discussed together with the inherent problems in diagnosis.

Collie eye anomaly: a review

“…Intraocular haemorrhage is not common. Bedford (1982b) found it in approximately 1% of dogs with CEA only. It may appear as unclotted blood in the anterior eye chamber or as pre-retinal bleeding and is most likely to result from bleeding from abnormal vessels in the retina.…”

“…Thanks to the congenital presence of the disease, early ophthalmoscopic diagnosis is possible. The examination is both practicable and advisable at six weeks of age (Bedford 1982b). A problem in diagnosis is the "go normal" phenomenon.…”

“…Chorioretinal changes of minor extent found on examination before three months of age can be masked by later retinal pigmentation. Such dogs, which then appear normal, have been classified as "go normals" (Bedford 1982b). …”

“…The first signs to be described were observed in 35 mm long Collie embryos as a rosette-like structure near the optic disc adjacent to the optic fissure (Latshaw et al 1969). Ophthalmoscopic examination can uncover one or more of the following abnormalities: excessive tortuosity of the retinal blood vessels; chorioretinal dysplasia (CRD); coloboma in or in the region of, the optic nerve head; retinal detachment; and intraocular haemorrhage (Donovan and Wyman 1965; doi: 10.17221/8381-VETMED Donovan et al 1969;Yakely 1972;Stades and Barnet 1981;Bedford1982a;Bedford 1982b;Bjerkas 1991;Wallin-Hakanson et al 2000). Defect of the sclera (colobomatous lesions) may also be present (Lowe et al 2003).…”

Simplified PCR analysis of a mutation in the NHEJ1 gene causing collie eye anomaly in some dog breeds

“…The genetic cause of this variability is unknown. Yakely (1972) reported CEA in 70-97% Rough and Smooth Collies in the USA, likewise Bedford (1982a) in Great Britain. Wallin-Hakanson et al (2000) observed CEA in approximately 68% of Rough Collies in Sweden.…”