Description: PRA-cord1 is one form of progressive retinal atrophy (PRA). This retinal degenerative disease, CORD (cone-rod dystrophy 1), occurs in both humans and dogs. The first clinical symptoms of cord1-PRA described in miniature long-haired dachshunds are evident in an ERG examination at about 6 months of age. First, degeneration of the cone and then the rod is recorded. At about 40 weeks of age, no photoreceptor function was detected by the ERG in an animal affected by PRA-cord1. The different age at the onset of the first clinical symptoms of CORD1 does not exclude the possible existence of a modifying gene or the presence of modifying genes. These genes could affect the penetrance and expressivity of CORD1 disease (or mutation RPGRIP1). This hypothesis is currently not clearly confirmed.
Inheritance: autosomal recessive
Mutation: g. 8228_8229 insA29GGAAGCAACAGGATG) in exon 2 of the RPGRIP1 gene
Sample: EDTA whole blood (1.0 ml) or 2 buccal brushes. For official purposes, the confirmation of the dog’s identity by Veterinarian is recommended.
The analysis is suitable for the following breeds: Beagle, Boykin Spaniel, Clumber Spaniel, Curly Coated Retriever, Dachshund Miniature Long Hair, Dachshund Miniature Smooth-haired, Dachshund Miniature Wire-haired, Dachshund Standard Long-haired, Dachshund Standard Smooth-haired, English Springer Spaniel, Labrador Retriever, Chihuahua, Portuguese Warren Hound – portuguese Podengo, Russkaya Tsvetnaya Bolonka
Notes: In 2012, a study by Miyader et. al, which partially questioned the g. 8228_8229 insA29GGAAGCAACAGGATG as causal to cord1. In the study, dogs with a mutation in both alleles (mutated homozygotes) were found that lacked the clinical signs of the disease. The mechanism of PRA-cord1 seems to be more complex than initially seemed. Further research continues at the level of investigation of the transcription mechanism of the RPGRIP1 gene, and the possibility of further mutations is not excluded.