Canine Multifocal Retinopathy 3 (CMR3)

Quick Summary

Canine multifocal retinopathy 3 is an inherited eye disease characterized by areas of retinal detachment. The disease does not typically lead to blindness or vision deficits. The CMR3 mutation is associated with the Finnish Lapphund, Lapponian Herder, and Swedish Lapphund breeds.
Search Keywords
CMR
CMR3
retinopathy

Phenotype: Affected dogs typically present with multiple, discrete circular areas of retinal detachment between 9 and 24 months of age. Fluid accumulates under the detached retina resulting in gray, tan, orange or pink “blisters” in the eye. Progression of retinal changes is usually slow and does not lead to blindness. In some cases the blisters appear to heal as the dog ages but vision loss has been reported.

Mode of Inheritance: Autosomal recessive

Alleles: N = Normal, CMR3 = Canine multifocal retinopathy 3

Breeds appropriate for testing: Finnish Lapphund, Lapponian Herder, Swedish Lapphund

Explanation of Results:

  • Dogs with N/N genotype will not have canine multifocal retinopathy 3 and cannot transmit this CMR3 variant to their offspring.
  • Dogs with N/CMR3 genotype will not have canine multifocal retinopathy 3, but are carriers. They will transmit this CMR3 variant to 50% of their offspring. Matings between two carriers are predicted to produce 25% canine multifocal retinopathy 3-affected puppies.
  • Dogs with CMR3/CMR3 genotype will develop canine multifocal retinopathy 3, an eye disease, and will transmit this variant to all of their offspring.

Results of this test can be submitted to the OFA (Orthopedic Foundation for Animals)

Price

$50 one test per animal
$30 as additional test (same animal)
Additional $5 discount on 3 or more dogs

Additional Details

Canine multifocal retinopathy 3 (CMR3) is an inherited eye disease caused by two sequence alterations in the Bestrophin 1 gene, a deletion (C1388del) and substitution (G1466T), that result in incomplete protein formation. Affected dogs typically present with multiple, discrete circular areas of retinal detachment between 9 and 24 months of age. Fluid accumulates under the detached retina resulting in gray, tan, orange or pink “blisters” in the eye. Progression of retinal changes is usually slow and does not lead to blindness. In some cases the blisters appear to heal as the dog ages but vision loss has been reported. The disease is inherited in an autosomal recessive fashion thus two copies a must be present to cause the disease. Breeding two carriers is predicted to produce 25% affected pups.

The VGL offers a genetic test for CMR1, CMR2, and CMR3 mutations. Genetic screening helps breeders establish the genetic status of breeding stock and select mating pairs appropriately in order to reduce the risk of producing affected offspring.

 

Note: CMR1, CMR2, CMR3 mutations have different breed origins and distributions and thus test selection needs to be breed-appropriate. See "Breeds appropriate for testing" list on each page.
Turnaround Time
5-10 business days

Species

Dog

Type of Test

Results Reported As
Test Result Canine multifocal retinopathy 3

N/N

Normal. No copies of the CMR3 mutation.

N/CMR3

Carrier. 1 copy of the CMR3 mutation. Dog is normal.

CMR3/CMR3

Affected. 2 copies of the CMR3 mutation. Dog will develop multifocal retinopathy.

References

Guziewicz, K.E., Zangerl, B., Lindauer, S.J., Mullins, R.F., Sandmeyer, L.S., Grahn, B.H., Stone, E.M., Acland, G.M., & Aguirre, G.D. (2007). Bestrophin gene mutations cause canine multifocal retinopathy: a novel animal model for Best disease. Investigative Ophthalmology & Visual Science, 48(5), 1959-67. doi: 10.1167/iovs.06-1374

Zangerl, B., Wickström, K., Slavik, J., Lindauer, S.J., Ahonen, S., Schelling, C., Lohi, H., Guziewicz, K.E., & Aguirre, G.D. (2010). Assessment of canine BEST1 variations identifies new mutations and establishes an independent bestrophinopathy model (cmr3). Molecular Vision, 16, 2791-804. [PubMed: 21197113]