In other species: dog , domestic cat

Categories: Vision / eye phene

Links to MONDO diseases: No links.

Mendelian trait/disorder: unknown

Mode of inheritance: Probably autosomal recessive

Considered a defect: yes

Cross-species summary: Progressive, non-inflammatory degeneration or dysplasia of rods and cones or just of rods, leading to firstly night blindness, and later to blindness during the day.

Species-specific description: Hunt et al. (2022) report a suspected autosomal recessive form of progressive retinal atrophy in Wiltshire sheep.

Inheritance: Hunt et al. (2022) "pedigree analysis suggested an inherited basis for the disease. Mating an affected Wiltshire ram to 2 affected Wiltshire ewes resulted in 6 progeny that all developed retinal degeneration by 2 years of age, while mating of the same affected ram to 6 unaffected ewes resulted in 8 unaffected progeny, consistent with autosomal recessive inheritance."

Mapping: Hunt et al. (2022) "Homozygosity mapping of 5 affected Wiltshire sheep and 1 unaffected Wiltshire sheep using an OvineSNP50 Genotyping BeadChip revealed an identical-by-descent region on chromosome 5, but none of the genes within this region were considered plausible candidate genes. Whole-genome sequencing of 2 affected sheep did not reveal any significant mutations in any of the genes associated with retinitis pigmentosa in humans or progressive retinal atrophy in dogs."

Genetic engineering: Unknown
Have human generated variants been created, e.g. through genetic engineering and gene editing

Clinical features: Hunt et al. (2022): "Affected [Wiltshire] sheep developed night blindness between 2 and 3 years of age, which progressed to complete blindness by 4 to 5 years of age. Fundic examination findings included progressive tapetal hyperreflectivity and attenuation of retinal blood vessels."

Pathology: Hunt et al. (2022): "Histologically, the retinas had a selective loss of rod photoreceptors with initial preservation of cone photoreceptors. Retinal degeneration was not accompanied by any other ocular or central nervous system abnormalities ..."

Breed: Wiltshire Horn (Sheep) (VBO_0001688).
Breeds in which the phene has been documented. For breeds in which a likely causal variant has been documented, see the variant table below