Papillon PRA Type I Pap_PRA1 Test Code 308
For breeds: Papillon and Phalene
Progressive Retinal Atrophy in the Papillion and Phalele breeds, Pap_ PRA1, is a late onset inherited eye
disease characterized by a slow degeneration of rod photoreceptors. The affected dogs start to show clinical signs of the disease and poor vision in dim light between 4 and 6 years of age.
A mutation in the CNGB1 gene associated with the Pap_PRA1 has been identified in the Papillion breed (1, 2). The Pap_PRA1 is inherited in an autosomal recessive manner, meaning that two copies of the mutation must be inherited in order for disease to occur.
The Pap_PRA1 test results are reported as one of three outcomes:
Normal/Clear—These dogs do not carry the Pap_PRA1 mutation. They will not develop the form of PRA due to the Pap_PRA1 mutation. These dogs may be mated to any other dog and no offspring affected with Pap_PRA1 will be produced.
Carrier—These dogs carry ONE copy of the Pap_PRA1 mutation. They will not develop the form of PRA due to the Pap_PRA1 mutation but they CAN pass the mutation on to their offspring. They should only be mated to a dog that is genetically Normal/Clear to avoid producing PRA1-affected progeny due to the Pap_PRA1 mutation.
Affected—These dogs carry two copies of the Pap_PRA1 mutation and it can be expected that they will develop PRA1 in their lifetime.
It is recommended to test dogs
prior to mating and to ensure that at least one parent is Normal/Clear of the mutation to avoid production of affected progeny.
Expected results for breeding
strategies using the|
Parent 1 |
|Parent 2 Genotype|
Normal/Clear||1/2 = Normal/Clear|
|Carrier||1/2 = Normal|
|1/4 = Normal/Clear |
1/2 = Carrier
1/4 = Affected
|1/2 = Carrier|
|Affected ||All =
|1/2 = Carrier|
Note: There is more than one form of
PRA occurring in the Papillon and Phalene breeds. Unfortunately, only one form, caused
by the Pap_PRA1 mutation, is currently detectable by DNA testing.
Ongoing research will hopefully identify other mutation(s) responsible
for PRA in the breed. If you know of any PRA-affected Papillons that
have been diagnosed by a veterinary ophthalmologist, please encourage
the owners to contact OptiGen to learn about Free DNA testing for these
dogs and the ongoing PRA research.
1. Ahonen SJ, Arumilli M, Lohi
H. A CNGB1 frameshift mutation in Papillon and Phalène dogs with
progressive retinal atrophy. PLoS One. 2013 Aug 28;8(8):e72122.
2. Winkler PA, Ekenstedt KJ,
Occelli LM, Frattaroli AV, Bartoe JT, Venta PJ, Petersen-Jones SM. A large
animal model for CNGB1 autosomal recessive retinitis pigmentosa. PLoS One.
2013 Aug 19;8(8):e72229