Progressive retinal atrophy / PRA3 (FAM161A-related) - Tibetan Spaniel / Tibetan Terrier

What does this test examine?

This genetic test analyses the FAM161A SINE insertion in the Tibetan Spaniel / Tibetan Terrier. The condition is known as progressive retinal atrophy / PRA, PRA3, Tibetan type, FAM161A-PRA and progressive retinal degeneration. This form is known as PRA3 or the Tibetan type and is mainly used in Tibetan Spaniel and Tibetan Terrier.

What does this condition mean?

Progressive retinal atrophy is a group name for inherited retinal diseases in which photoreceptors gradually degenerate. It often starts with night blindness or uncertainty in dim light, followed by loss of daytime vision and possible blindness. Affected dogs often first show night blindness between about three and seven years; vision can then decline rapidly.

• Clear: the dog does not carry the tested variant or marker.
• Carrier: the dog carries one copy and can pass it on.
• Affected: two copies cause the tested inherited PRA risk.

Practical value of this test

This test is useful for breeders and owners who want to include inherited eye health in breeding decisions. Because PRA often becomes visible later, DNA information can clarify carrier status, affected genotypes and risk combinations before breeding age.

• Supports targeted breeding plans and mate selection.
• Helps identify carriers before the variant spreads unnoticed through a line.
• Separates clear dogs, carriers and dogs with the affected genotype.
• Gives clear information for vision follow-up, lines and family history.

Inheritance and interpretation

The trait is inherited in an autosomal recessive manner. A carrier is usually not affected, but can pass the variant on. When two carriers are bred together, some offspring can inherit two copies and receive the affected genotype. Not all PRA in these breeds is explained by PRA3; this test gives specific information about the FAM161A SINE insertion.