Progressive Retinal Atrophy (CNGA1 type)

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Find out if your Shetland Sheepdog could develop Progressive Retinal Atrophy (PRA) caused by CNGA1 at CAGT.

Categories ,
Turnaround 1-2 weeks
OMIA OMIA001977-9615
Aliases ,

Results from this test will be reported as detailed in the Registry Reporting list.


Part of the official UK Kennel Club testing scheme in Shetland Sheepdog

Progressive retinal atrophy (PRA) is the most common form of inherited disease affecting the retina in dogs. Genetically different forms of PRA, caused by mutations in different genes, affect many breeds of dog with each form usually affecting one or a small number of breeds. PRA is characterised by progressive degeneration of the retina at the back of the eye and leads to vision loss and blindness.

This specific form of PRA is caused by a mutation in a gene called CNGA1 and is indistinguishable from other forms of PRA in other breeds. The average age of onset of clinical signs is around 5 years, but can be anything between 2 and 11 years. In humans, mutations in CNGA1 are associated with a condition known as Retinitis Pigmentosa, symptoms of which include loss of peripheral vision and the ability to see at night. There is no cure for this form of PRA, but using the DNA test to identify dogs that carry the mutation in CNGA1 will prevent further spread of this blinding condition in this lovely breed.

Autosomal Recessive

Our advice is to breed with carrier animals for the first few generations after the development of a DNA test. This ensures that desirable traits in the breed can be captured.

Carriers can be safely bred to clear dogs. On average, 50% of such a litter will be clear and 50% carriers; there will be no affected dogs produced from such a mating.

Puppies which will be used for breeding should themselves be DNA tested to determine whether they are clear or carriers of this PRA mutation.

Gene CNGA1
Variant 4 base-pair deletion (c.1752_1755delAACT)
Assay Type Variant Specific
Inheritance Autosomal Recessive
Severity Low-Moderate: Affected animals experience discomfort or dysfunction of some kind, but life expectancy is not affected.

Wiik AC, Ropstad EO, Ekesten B, et al. (2015) Progressive retinal atrophy in Shetland sheepdog is associated with a mutation in the CNGA1 gene. Anim Genet. 46(5): 515-521. DOI: 10.1111/age.12323.

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