Affected gene: NHEJ1
Inheritance: Autosomal Recessive with variable penetrance
Mutation: Deletion of 7.8kb in the NHEJ1 gene: 37:g.28,697,542–28,705,340del. CanFam3.1    37    g.25698028_25705826del    c.588+462_588+8260del
OMIA link: 000218-9615

Appropriate breeds for testing: Miniature American Shepherd, Australian Shepherd, Miniature Australian Shepherd, Toy Australian Shepherd, Shetland Shepherd, Border Collie, Collie, Shorthaired Collie, Longhaired Collie, Boykin Spaniel, Lancashire Heeler, Whippet Greyhound, Longhaired Whippet Greyhound,  Nova Scotia Duck Tolling retriever

Symptoms:
Collie eye anomaly is an inherited eye disorder that is prevalent in sheepdog breeds. CEA presents with varying levels of visual impairment, ranging from no visual impairment to complete blindness. Clinically, the disease results in poor development of the choroid and sclera.

References:
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.
Chang, HS., Mizukami, K., Yabuki, A., Hossain, MA., Rahman, MM., Uddin, MM., Arai, T., Yamato, O. :    
A novel rapid genotyping technique for Collie eye anomaly: SYBR Green-based real-time polymerase chain reaction method applicable to blood and saliva specimens on Flinders Technology Associates filter paper. J Vet Diagn Invest 22:708-15, 2010. Pubmed reference: 20807925.
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.
Mizukami, K., Yabuki, A., Kohyama, M., Kushida, K., Rahman, M.M., Uddin, M.M., Sawa, M., Yamato, O. :    
Molecular prevalence of multiple genetic disorders in Border collies in Japan and recommendations for genetic counselling. Vet J 214:21-3, 2016. Pubmed reference: 27387721. DOI: 10.1016/j.tvjl.2016.05.004.
Gray, A.P., Sato, Y., Miyadera, K., Aguirre, G.D. :    
Novel insights into chorioretinal and juxtapapillary colobomas by optical coherence tomography. Vet Ophthalmol :, 2022. Pubmed reference: 35092136. DOI: 10.1111/vop.12970.