Progressive retinal atrophy (NECAP1-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 and retinal vascular attenuation. Genetic testing complements clinical eye examinations with the advantage of detecting known PRA mutations before breeding age or before clinical signs present. In the breed Giant Schnauzer, a variant in the so-called NECAP1-gene could be associated with a novel form of PRA. The onset of first symptoms of this PRA form is described at the age of around 4 years. The NECAP1- gene encodes for a protein that is involved in the clathrin mediated endocytosis (CME) in synapses. As a consequence of CME disturbance in the retina of affected dogs, rhodopsin is suspected to accumulate in the photoreceptors, leading to cell death and retinal degeneration.