Cone-rod dystrophy (CRD) is a type of PRA affecting Dachshunds. It is an autosomal recessive inherited disorder.
The disease first affects the cones in the retina which initially results in day blindness for sufferers, and then the rods begin degenerating secondarily.
Progressive retinal atrophy (PRA) is a disease of the retina.
Affected dogs show symptoms of vision loss or retinal disease on eye examination.
DNA testing is available to identify clear, carrier and affected dogs.
Clear: the dog has 2 copies of the normal gene and will not develop this form of PRA or pass a copy of the CRD (NPHP4) mutation to any of its offspring.
Carrier: the dog has one copy of the normal gene and one copy of the mutant gene that causes that causes the CRD (NPHP4) form of PRA in Standard Wire -haired Dachshunds. It will not develop the condition but will pass on the CRD (NPHP4) mutation to on average 50% of its offspring. Carriers may still be bred to clear dogs as there will be no genetically affected puppies produced.
Affected: the dog has two copies of the CRD (NPHP4) mutation and is highly likely to develop this cone-rod dystrophy form of PRA at some stage during their lifetime. Affected dogs will pass on a copy of the mutation to any offspring.
Gene Tested : NPHP4