Possibly relevant human trait(s) and/or gene(s)s (MIM numbers): 610598 (gene) , 610599 (trait)

Mendelian trait/disorder: yes

Mode of inheritance: Autosomal Recessive

Considered a defect: yes

Key variant known: yes

Year key variant first reported: 2006

Cross-species summary: This disorder has been renamed in OMIA on the basis of the review by Miyadera et al. (2012)

Species-specific symbol: prcd

Mapping: Using the power of comparative mapping, Acland et al. (1998) showed that this disorder in dogs maps to the same location as the gene for retinitis pigmentosa 17 in humans.

Molecular basis: Zangerl et al. (2006) identified a novel gene that they called PRCD in a 106kb candidate region on CFA9. They also showed that "a homozygous mutation (TGC>TAC) in the second codon shows complete concordance with the disorder in 18 different dog breeds/breed varieties tested".

Prevalence: Lewis and Mellersh (2019) reported a decline in frequency of the PRCD:c.5G>A variant in Labrador Retrievers from 0.078 (7.8%) prior to publication of the variant, to 0.003 (0.3%) 8-10 years after publication of the variant. This represents a 96.5% decline in frequency of the variant as a result of testing. For the same variant in English Cocker Spaniels, the equivalent results were a decline in frequency from 0.126 (12.6%) to 0.006 (0.6%) 8-10 years after publication of the variant, which represents a decline in frequency of 95.1% as a result of testing.

Andrade et al. (2019) reported the frequency of this same variant in English Cocker Spaniels in Brazil: "220 ECS dogs was used for genotyping, of which 131 were registered from 18 different kennels and 89 were unregistered. . . . The . . .[PRCD:c.5G>A] allele frequency was 25.5%. Among the registered dogs, the allele frequency was 14.9%; among the dogs with no history of registration, the allele frequency was 41%."

Breeds: American Cocker Spaniel, Australian Cattle Dog, Australian Shepherd, Australian Stumpy Tail Cattle Dog, Chesapeake Bay Retriever, Chinese Crested Dog, English Cocker Spaniel, Entlebucher mountain dog, Finnish Lapphund, Golden Retriever, Karelian bear dog, Kuvasz, Labrador Retriever, Lapponian Herder , Miniature Poodle, Norwegian Elkhound, Nova Scotia Duck Tolling retriever, Portugese water dog, Spanish water dog, Swedish Lapphund, Toy Poodle, Yorkshire Terrier.

Associated gene: