Progressive retinal atrophy (IFT122-PRA)

Canine progressive retinal atrophies (PRA) are genetically heterogeneous diseases characterized by retinal degeneration and subsequent blindness. While there are PRA mutations that are shared by multiple breeds, many seem to be private to a single breed or are found in breeds sharing similar ancestral backgrounds. Typical signs found by ophthalmoscopic examination are widespread tapetal hyper-reflectivity resulting from retinal thinning, retinal vascular attenuation and at later stages atrophy of the optic nerve head.
In Lapponian herders, several types of inherited retinal dystrophies are known. However, not all cases could be explained by the already identified genetic variants causing prcd-PRA and canine multifocal retinoatrophie 3 (CMR3). A genetic variant of the intraflagellar transport 122 (IFT122) gene has been found to be associated with another form of PRA in this breed. The IFT122-variant is inherited in an autosomal recessive manner. Typical first symptoms of IFT122-PRA affected dogs are night blindness and diffuse tapetal hyperreflectivity. The PRA is usually diagnosed at the age of 5 - 12 years. Since disease progression is slow, some dogs still have some visual capacity left at the age of 13 years.