Peer-reviewed veterinary case report
Genetic factor affecting retinal degeneration onset
By Miyadera, Keiko et al.·Published in Mammalian genome : official journal of the International Mammalian Genome Society·2012·Department of Veterinary Medicine, United Kingdom·View original on PubMed →
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Original publication title: Genome-wide association study in RPGRIP1(-/-) dogs identifies a modifier locus that determines the onset of retinal degeneration.
- Species:
- dog
Plain-English summary
A group of Miniature Longhaired Dachshunds with a genetic mutation causing retinal degeneration (CRD) were studied to understand why some dogs went blind earlier than others. Researchers found that a specific genetic change on chromosome 15 was linked to early-onset blindness, while dogs with just the RPGRIP1 mutation might not show any signs of vision loss until later or at all. This means that both genetic factors are needed for the dogs to develop early-onset retinal degeneration. Understanding these genetic influences can help in managing and predicting the condition in affected dogs.
People also search for: Miniature Longhaired Dachshund retinal degeneration · dog blindness genetic factors · early-onset retinal degeneration in dogs
Abstract
Cone-rod dystrophy (CRD) is a form of inherited retinal degeneration (RD) causing blindness in man as well as in several breeds of dog. Previously, a 44 bp insertion in RPGRIP1 (retinitis pigmentosa GTPase regulator interacting protein-1) was associated with a recessive early-onset CRD (cone-rod dystrophy 1, cord1) in a Miniature longhaired dachshund (MLHD) research colony. Yet in the MLHD pet population, extensive range of the onset age has been observed among RD cases, with some RPGRIP1(-/-) dogs lacking obvious clinical signs. Phenotypic variation has been known in human homologous diseases, including retinitis pigmentosa and Leber congenital amaurosis, indicating possible involvement of modifiers. To explore additional genetic loci associated with the phenotypic variation observed in MLHDs, a genome-wide association study was carried out using Canine SNP20 arrays in 83 RPGRIP1(-/-) MLHDs with variable ages of onset or no clinical abnormality. Using these samples, comparison of 31 early-onset RD cases against 49 controls (15 late-onset RD and 34 normal dogs combined) identified a strong association (P = 5.05 × 10(-13)) at a single locus on canine chromosome 15. At this locus, the majority of early-onset RD cases but few of the controls were homozygous for a 1.49 Mb interval containing ~11 genes. We conclude that homozygosity at both RPGRIP1 and the newly mapped second locus is necessary to develop early-onset RD, whereas RPGRIP1(-/-) alone leads to late-onset RD or no apparent clinical phenotype. This study establishes a unique model of canine RD requiring homozygous mutations at two distinct genetic loci for the manifestation of early-onset RD.
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Search related cases →Original publication on PubMed: https://pubmed.ncbi.nlm.nih.gov/22193413/