Progressive retinal atrophy / PRA1 type B (HIVEP3 marker) - Miniature Schnauzer

What does this test examine?

This genetic test analyses the HIVEP3 g.1432293G>A as a strong genetic marker in the Miniature Schnauzer. The condition is known as progressive retinal atrophy / PRA, PRA1 type B, Type B PRA, HIVEP3/PPT1-PRA, retinitis pigmentosa and photoreceptor dysplasia. This test is used as a strong genetic marker for PRA1 type B. The HIVEP3 marker is practical to test, while the most likely causal PPT1 structural variant is technically much harder to type reliably.

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. Type B PRA in the Miniature Schnauzer can lead to progressive vision loss and many affected dogs become blind at a relatively young age.

• Clear: the dog does not carry the tested variant or marker.
• Carrier: the dog carries one copy and can pass it on.
• High-risk marker: two copies indicate a strongly increased risk for this PRA type.

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. Because this is a marker analysis, the result is used as strong risk information for this PRA type rather than as a simple causal HIVEP3 claim.