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HIGH QUALITY DNA
TESTING YOU CAN TRUST
OUR PANELS
The tests in our DNA health testing panels are selected based on the scientific evidence available for disorders in the breed. Our scientists stay up to date with the latest developments and discoveries in the field to ensure that our testing panels are as up-to-date as possible.
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TESTIMONIALS
approx. 2 weeks
Typical turnaround
1
Conditions screened
Simple cheek swab
At-home sampling
UK laboratory
Tested in-house
Collie Eye AnomalyCEA
Collie Eye Anomaly (CEA), also known as Choroidal Hypoplasia, is an inherited eye condition caused by a variant associated with the NHEJ1 gene. It affects the development of the eye and can range from no obvious vision problems to more serious changes that may lead to partial or complete blindness. CEA is inherited as an autosomal recessive condition, meaning a dog must inherit two copies of the associated variant to be genetically affected.
How it's inherited
Recessive
What your result means
Clear (N/N): no copies; not expected to develop CEA, nor pass it on.
Carrier (N/CEA): one copy. Healthy, but can pass it on. Breeding two carriers risks affected puppies.
Affected (CEA/CEA): two copies; expected to develop CEA. Discuss with your vet.
Collie Eye AnomalyCEA
- Gene
- NHEJ1
- Variant
- 37:g.28,697,542–28,705,340del
- Inheritance
- autosomal recessive
- OMIA
- OMIA000218 9615
Molecular mechanism
Collie Eye Anomaly (CEA), now more broadly referred to as Choroidal Hypoplasia, is an inherited developmental disorder of the eye characterised primarily by underdevelopment of the choroid, with severity ranging from no detectable visual impairment to complete blindness. Affected dogs may also develop colobomas, retinal folds and, in more severe cases, retinal detachment and intraocular haemorrhage, which can result in permanent vision loss (Lowe et al., 2003; Fredholm et al., 2016).
Collie Eye Anomaly is inherited as an autosomal recessive condition with variable clinical expression. Parker et al., (2007) identified a 7.8 kb deletion (37.28,697,542–28,705,340del) associated with CEA within the NHEJ1 gene on canine chromosome 37 (CFA37), which is widely used as the genetic marker for CEA screening. Although subsequent studies have suggested that this deletion may be linked to, rather than be the causative variant in, some breed populations, it remains strongly associated with the disease and is widely used for genetic testing (Fredholm et al., 2016; Brown et al., 2018; Clark et al., 2023).
References
Brown, E.A., Thomasy, S.M., Murphy, C.J., Bannasch, D.L. : Genetic analysis of optic nerve head coloboma in the Nova Scotia Duck Tolling Retriever identifies discordance with the NHEJ1 intronic deletion (collie eye anomaly mutation). Vet Ophthalmol 21:144-150, 2018. Pubmed reference: 28702949. DOI: 10.1111/vop.12488.
Clark, J.A., Anderson, H., Donner, J., Pearce-Kelling, S., Ekenstedt, K.J. : Global frequency analyses of canine progressive rod-cone degeneration-progressive retinal atrophy and Collie eye anomaly using commercial genetic testing data. Genes (Basel) 14:2093, 2023. Pubmed reference: 38003037. DOI: 10.3390/genes14112093.
Fredholm, M., Larsen, R.C., Jönsson, M., Söderlund, M.A., Hardon, T., Proschowsky, H.F. : Discrepancy in compliance between the clinical and genetic diagnosis of choroidal hypoplasia in Danish Rough Collies and Shetland Sheepdogs. Anim Genet 47:250-2, 2016. Pubmed reference: 26732749. DOI: 10.1111/age.12405.
Lowe, JK., Kukekova, AV., Kirkness, EF., Langlois, MC., Aguirre, GD., Acland, GM., Ostrander, EA. : Linkage mapping of the primary disease locus for collie eye anomaly. Genomics 82:86-95, 2003. Pubmed reference: 12809679.
Parker, H.G., Kukekova, A.V., Akey, D.T., Goldstein, O., Kirkness, E.F., Baysac, K.C., Mosher, D.S., Aguirre, G.D., Acland, G.M., Ostrander, E.A. : Breed relationships facilitate fine-mapping studies: a 7.8-kb deletion cosegregates with Collie eye anomaly across multiple dog breeds. Genome Res 17:1562-71, 2007. Pubmed reference: 17916641. DOI: 10.1101/gr.6772807
