Dog (Canis lupus familiaris) — Generalized PRA (gPRA), early‑onset progressive retinal atrophy (hereditary; OMIA-verified species predisposition)
Source: first-hand OMIA (University of Sydney) species-specific hereditary-disorder record, saved verbatim to source_file; every claim below is a C1 byte-substring of it.
Claims
Species: Dog (Canis lupus familiaris)Disorder: Generalized PRA (gPRA), early‑onset progressive retinal atrophyClin feat: Lippman et al. (2007): "gPRA in Schapendoes is characterized by late onset and slow progression ... . Affected Schapendoes dogs appear normal when young, but develop gPRA at an age of onset between 2-5 years. Early in the disease, affected dogs are night-blind, lacking the ability to adjust their vision to dim light; later, their daytime vision also fails. This process of complete photoreceptor degeneration takes up to 2 years." Murgiano et al. (2020) describe the clinical signs in Portugese water dogs: "...visual deficits, including difficulty following moving objects and walking into still objects, which were reportedly worse under dim light, consistent with nyctalopia. These signs became progressively worse, compromising the animals’ vision under both dim and well-lit conditions. The age of onset was determined by the time point at which the visual deficits became noticeable to the owners or when ophthalmoscopic abnormalities were first noted. The male proband and the two affected females had decreased vision per the owner at initial presentation and were diagnosed ophthalmoscopically as EOPRA with an age of onset at 2 years. A second male dog had no obvious visual deficit per the owner at initial presentation at age 2 years and had unremarkable fundus when examined ophthalmoscopically. However, peripapillar changes suggestive of PRA developed by 3 years of age at which time electroretinography (ERG) was recommended but declined. This dog was re-examined at 6 years of age when visual impairment was evident, ERGs were undetectable ..., and ophthalmoscopic changes were consistent with mid-stage disease. The ophthalmoscopic changes observed were common in all affected dogs, characterized by generalized tapetal hyper-reflectivity, diffuse vascular attenuation, optic disc pallor, and multifocal depigmenta-tion of the non-tapetal fundus. .... A feature that was unique to this disease in all affected dogs was a distinct peripapillary ring of hyper-reflectivity or peripapillary conus ..., which progressed into a broader zone of hyper-reflectivity around the optic disc in advanced disease ... ."Pathology: Lippman et al. (2007): "Compared to a normal retina ..., the gPRA-affected eyes of a five year old Schapendoes displayed typical degeneration signs in peripheral and central areas ... . The outer retina with the photoreceptor layer and the outer nuclear layer was missing in all retinal parts investigated. The inner retina showed reduced inner nuclear and inner plexiform layers, whereas the ganglion cell layer appeared comparatively preserved."
Associated gene(s)
Derived from OMIA database dump (omia.xml, local); structured field, not verbatim prose. First-hand values below are verbatim substrings of the topic's pdf-raw/omia/<phene_id>.txt source file.
- Gene: Entrez Gene ID 26582962 (no symbol in OMIA GeneSynonym) — OMIA Phene_Gene
- OMIA molecular-genetics note: Dekomien et al. (2010): "Mutation screening of the CCDC66 gene revealed a 1-bp insertion in exon 6 leading to a stop codon as the underlying cause of disease" for generalized progressive retinal atrophy on in the Schapendoes breed. Murgiano et al. (2020): "Whole‑genome sequencing in one affected [Portugese water] dog and its obligatory carrier parents identified a 1 bp insertion (CFA20:g.33,717,70…
Evidence (references)
Derived from OMIA database dump (omia.xml, local); structured field, not verbatim prose. First-hand values below are verbatim substrings of the topic's pdf-raw/omia/<phene_id>.txt source file.
- 2010. Progressive retinal atrophy in Schapendoes dogs: mutation of the newly identified CCDC66 gene. Neurogenetics — PubMed:PMID19777273 | DOI:10.1007/s10048-009-0223-z — OMIA Phene_Article / Article
- 2007. Haplotype-defined linkage region for gPRA in Schapendoes dogs. Mol Vis — PubMed:PMID17327822 — OMIA Phene_Article / Article
- 2012. Genetic and phenotypic variations of inherited retinal diseases in dogs: the power of within- and across-breed studies. Mamm Genome — PubMed:PMID22065099 | DOI:10.1007/s00335-011-9361-3 — OMIA Phene_Article / Article
- 2020. CCDC66 frameshift variant associated with a new form of early-onset progressive retinal atrophy in Portuguese Water Dogs. Sci Rep — PubMed:PMID33273526 | DOI:10.1038/s41598-020-77980-5 — OMIA Phene_Article / Article
- 2021. The Blue Book: Ocular disorders presumed to be inherited in purebred dogs. 13th Edition. https://ofa.org/wp-content/uploads/2022/10/ACVO-Blue-Book-2021.pdf — OMIA Phene_Article / Article
- 2023. Genotypic and allelic frequencies of progressive rod-cone degeneration and other main variants associated with progressive retinal atrophy in Italian dogs. Vet Rec Open — PubMed:PMID38028226 | DOI:10.1002/vro2.77 — OMIA Phene_Article / Article
- 2024. Consensus guidelines for nomenclature of companion animal inherited retinal disorders. Vet Ophthalmol — PubMed:PMID38334230 | DOI:10.1111/vop.13185 — OMIA Phene_Article / Article