Progressive retinal atrophy (PRA) is a category of different progressive conditions leading to retinal atrophy and potential blindness. Cone-Rod dystrophy 4 (PRA-CORD1-CRD4) is an inherited eye disease affecting Dachshunds and English Springer Spaniels that leads to degeneration of both retinal rod and cone cells affecting vision in both low and bright light. Onset of symptoms can be seen starting at less than a year old until about 5 years of age with the average being around 3 years of age. However, the onset can vary significantly with dogs as old as 15 years being diagnosed. This mutation shows what is known as incomplete penetrance which means dogs that test At Risk/Affected may not develop symptoms of the disease which would suggest other factors (genetic and environmental) may play a role in disease progression. Following diagnosis, the disease can progress slowly but typically leads to complete blindness.
- English Springer Spaniel
- Miniature Long-Haired Dachshund
- Miniature Wire-Haired Dachshund
- Miniature Smooth-Haired Dachshund
A (CLEAR/NORMAL): These dogs have two copies of the normal gene and will neither develop PRA-CORD1-CRD4 progressive retinal atrophy nor pass this mutation to their offspring.
B (CARRIER/NOT AFFECTED): These dogs have one copy of the normal gene and one copy of the mutation associated with this disease. They will not develop PRA-CORD1-CRD4 progressive retinal atrophy but will, if bred, pass the mutation to 50% of its offspring, on average.
C (AT RISK/AFFECTED): These dogs have two copies of the mutation associated with this disease and are susceptible to developing progressive retinal atrophy.