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Multifocal Retinopathy 1

Multifocal Retinopathy 1 is an inherited retinal disorder in dogs that causes multiple areas of retinal detachment, potentially leading to vision problems.

Affected Genes: BEST1

Inheritance: Autosomal Recessive

Variant(canFam6):
chr18:53060882: G>A

Breed: American Bulldog
American Bully
Aussiedoodle
Australian Koolie
Australian Shepherd
Australian Working Kelpie
Brazilian Terrier
Bulldog
Bullmastiff
Cane Corso
Dogue de Bordeaux
French Bulldog
Great Pyrenees
Havanese
Koolie
Mastiff
Miniature American Shepherd
Miniature Australian Shepherd
Perro de Presa Canario
Pomsky
Shorty Bull*
South African Boerboel
Toy Australian Shepherd

General Information: Multifocal Retinopathy 1 is an inherited disorder affecting the retinas of several dog breeds, with symptoms typically appearing between 11 and 16 weeks of age. Affected dogs develop multiple discrete circular areas of retinal detachment with underlying fluid accumulation, which can be observed as blister-like lesions during a veterinary eye exam. These lesions, which may appear gray, tan, orange, or pink, are usually found in both eyes and can vary in number, size, and location. The progression of retinal changes is generally slow, with new lesions not forming after 6 to 12 months of age, and in some cases, lesions may heal and become undetectable over time. While the vision of most dogs remains unaffected, some may experience vision loss, making early diagnosis and monitoring crucial.

How to Read Your Dog's Test Results for this Genetic Variant:

Two Variants Detected: Dog Likely Affected

One Variant Detected: Dog Unlikely Affected

No Variants Detected: No Effect

Gene / Testing Information: Genetic testing of the BEST1 gene can determine whether a dog is a carrier of Multifocal Retinopathy 1, an autosomal recessive disorder. This condition requires a dog to inherit two copies of the mutated gene (one from each parent) to develop the disease. Carrier dogs, having only one copy of the mutation, do not show symptoms but can pass the gene to their offspring. Breeding two carriers together increases the risk of producing affected pups, with each pup having a 25% chance of inheriting the disease and a 50% chance of being a carrier of the BEST1 gene mutation. Reliable genetic testing is crucial for making informed breeding decisions to prevent the birth of affected puppies. Because visual deficits may not be immediately apparent and lesions can regress as dogs age, genetic testing should be conducted before breeding to help eliminate this mutation from breeding lines and avoid the potential of producing affected pups. Dogs that are not carriers do not have an increased risk of having affected offspring.

References:
Donner J, Kaukonen M, Anderson H, Moller F, Kyostila K, Sankari S, Hytonen M, Giger U, Lohi H. Genetic Panel Screening of Nearly 100 Mutations Reveals New Insights into the Breed Distribution of Risk Variants for Canine Hereditary Disorders. PLoS One 2016 11(8):e0161005.

Gornik KR, Pirie CG, Duker JS, Boudrieau RJ. Canine multifocal retinopathy caused by a BEST1 mutation in a Boerboel. Vet Ophthalmol. 2013 17(5):368-372.

Grahn BH, Philibert H, Cullen CL, Houston DM, Semple HA, Schmutz SM. Multifocal retinopathy of great Pyrenees dogs. Vet Ophthalmol. 1998 1(4):211-221.

Guziewicz KE, Slavik J, Lindauer SJ, Aguirre GD, Zangerl B. Molecular consequences of BEST1 gene mutations in canine multifocal retinopathy predict functional implications for human bestrophinopathies. Invest Ophthalmol Vis Sci. 2011 52(7):4497-4505.

Hoffmann I, Guziewicz KE, Zangerl B, Aguirre GD, Mardin CY. Canine multifocal retinopathy in the Australian Shepherd: a case report. Vet Ophthalmol. 2012 15(0 2): 134–138.