Collie eye anomaly
Collie eye anomaly (CEA; congenital posterior segment anomaly) is an autosomal-recessive genetic ocular disease of dogs characterized by choroidal hypoplasia, retinal detachment, intraocular hemorrhage and coloboma of the retina, uvea, sclera or optic disc and neuroretinal non-attachment.
CEA is inherited as an autosomal recessive trait that has a penetrance reaching 100 percent, and has been located to canine chromosome 37.
Prior to selective breeding programs to eliminate this disease from collie breeds, incidences of CEA in Collies were as high as 60% of breeding stock.
As the name suggests, this disease is frequently observed in the Collie breeds but also occurs in other breeds such as the Hokkaido dog, Border Collie, Shetland Sheepdog, Lancashire Heeler and Australian Shepherd, where coloboma and microphthalmia also occur.
Many dogs exhibit no obvious clinical consequences and retain apparently normal vision throughout life, while severely affected animals develop secondary retinal detachment, intraocular hemorrhage, and blindness.
At risk dogs can be tested from 10 weeks of age.
A tentative diagnosis can be attained with ophthalmic fundoscopy with characteristic choroidal hypoplasia in the bilateral temporal area adjacent to the optic nerve head, appearing as whitish areas.
Confirmation usually requires PCR and DNA testing of blood samples for the CEA-associated mutation.
There is no treatment for this condition and dogs blinded by this condition are often euthanized.
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