Canine Multifocal Retinopathy 3 (CMR3)

 

Gene: BEST1

Transmission: Autosomal recessive

For an autosomal recessive genetic disease an animal must have two copies of the mutation in question to be at risk of developing the disease.  Both parents of an affected animal must be carriers of at least one copy of the mutation.  Animals that have only one copy of the mutation are not at risk of developing the disease but are carrier animals that can pass the mutation on to future generations.

Mutation: Simple substitution, BEST1 gene, c.1388 del.C, exon10

Medical system: Eyes

Breeds: Finnish Lapphund, Lapponian Herder, Swedish Lapphund

Age of onset of symptoms: Around the age of 9 weeks to 2 years on a veterinary examination

Multifocal retinopathy 3 (CMR3) is a reported disease in Lapphund dogs.  Multiple regions of detachment appear in the retina around the age of 9 weeks to 2 years, causing retinal swellings of varying colors and sizes.  The disease progresses slowly. In some individuals, the lesions heal and are no longer visible. In general, vision is not affected, although some cases of blindness have been reported.

 

References:

OMIA link: [1554-9615]

Donner J, Freyer J, Davison S, et al. (2023) Genetic prevalence and clinical relevance of canine Mendelian disease variants in over one million dogs.  PLoS Genet. 19(2):e1010651. [pubmed/36848397]

Genetics Committee of the American College of Veterinary Opthalmologists (2021) The Blue Book: Ocular disorders presumed to be inherited in purebred dogs. 13th Edition.  [https://ofa.org/wp-content/uploads/2022/10/ACVO-Blue-Book-2021.pdf]

Guziewicz KE, Aguirre GD, Zangerl B. (2012) Modeling the Structural Consequences of BEST1 Missense Mutations. Adv Exp Med Biol 723:611-8. [pubmed/22183385]

Zangerl B, Wickstrom K, Slavik J, Lindauer SJ, et al. (2010) Assessment of canine BEST1 variations identifies new mutations and establishes an independent bestrophinopathy model (cmr3). Molecular Vision 16:2791-2804. [pubmed/21197113]

Guziewica KE, Zangerll B, Lindauer SJ, et al. (2007) Bestrophin gene mutations cause canine multifocal retinopathy: A novel animal model for Best disease. Investigative Ophthalmology and Visual Science 48(5):1959-1967. [pubmed/1746024]