CANINE MULTIFOCAL RETINOPATHY (CMR3)
The canine multifocal retinopathy mutation causes raised lesions to form on the retina which alters the
appearance of the eye but usually does not affect sight. The lesions may disappear, or may result in
minor retinal folding. Symptoms of the mutation usually appear when a puppy is only a few months old,
and generally do not worsen over time. The genetic test for CMR is valuable for identifying the cause of
a retinal deformation. Given the exact genetic diagnosis, the owner can be reassured that there
probably will be little or no vision loss due to this condition. While the CMR1, CMR2 and CMR3
mutations are in the same gene, they are breed specific and testing for only one is required. The CMR3
mutations is specific for the Lapponian Herder breed. The CMR2 mutation is specific for the Coton de
Tulear breed. All other breeds should test for the CMR1 mutation.
- Lapponian Herder
A (CLEAR/NORMAL): These dogs have two copies of the normal gene and will neither develop CMR
disorder 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 CMR disorder 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 develop retinal deformation.