Multifocal retinopathy

From Dog
Circular dark patches characteristic of multifocal retinopathy in an 18-month-old English Mastiff [1]

Canine multifocal retinopathy is an autosomal recessive genetic ocular disease characterized by retinal deformation[1].

This disease, which has been reported in the Great Pyrenees, Labradoodle[2], Coton de Tulear[3], Dogue De Bordeaux, English Mastiff, Cane Corso[4], Borzoi[5] and Lapponian Herder breeds, is caused by a missense bestrophin-1 gene mutation. This disease is similar to Best macular dystrophy in humans[6].

A number of variants of this disease have been observed. In the German Spitz[7], the disease is not caused by bestrophin mutation, and in the Great Pyrenees retinopathy, it manifests primarily as retinal pigment epithelium detachments[8].

Clinically affected dogs are often young (under 1 year of age) and have varying but progressive degrees of visual deficits, from asymptomatic to blindness (rare).

Testing can be done from 7 weeks of age in breeding animals.

Diagnosis usually requires fundoscopic examination, with characteristic subretinal accumulation of multiple gray-tan-pink subretinal patches, and discrete areas of tapetal hyper-reflectivity[9].

These lesions, looking somewhat like blisters, vary in location and size, although typically they are present in both eyes of the affected dog.

Fluorescein angiography is required for a definitive diagnosis[10].

A differential diagnosis would include Collie eye anomaly, progressive retinal atrophy, ivermectin sensitivity retinopathy[11], infectious anterior uveitis due to Blastomyces spp, Cryptococcus spp, metastatic lymphoma and serous detachments due to systemic hypertension or drug toxicities.

In most cases, multifocal retinopathy is a static disease with no or slow clinical progression over time. Systemic abnormalities have not been detected in affected dogs.

In most cases, treatment is not required.

References

  1. 1.0 1.1 Guziewicz KE et al (2007) Bestrophin gene mutations cause canine multifocal retinopathy: a novel animal model for best disease. Invest Ophthalmol Vis Sci 48:1959–1967
  2. Oliver JA & Gould DJ (2012) Survey of ophthalmic abnormalities in the labradoodle in the UK. Vet Rec 170(15):390
  3. Grahn BH et al (2008) Retinopathy of Coton de Tulear dogs: clinical manifestations, electroretinographic, ultrasonographic, fluorescein and indocyanine green angiographic, and optical coherence tomographic findings. Vet Ophthalmol 11(4):242-249
  4. Zangerl B et al (2010) Assessment of canine BEST1 variations identifies new mutations and establishes an independent bestrophinopathy model (cmr3). Mol Vis 16:2791-2804
  5. Storey ES et al (2005) Multifocal chorioretinal lesions in Borzoi dogs. Vet Ophthalmol 8(5):337-347
  6. Guziewicz KE et al (2007) Bestrophin gene mutations cause canine multifocal retinopathy: a novel animal model for best disease. Invest Ophthalmol Vis Sci 48(5):1959-1967
  7. Aguirre-Hernández J & Sargan DR (2010) Multifocal retinal dysplasia in the German Spitz (Klein and Mittel) is not caused by mutations in BEST1. Anim Genet 41(3):333-334
  8. Grahn BH et al (1999) Multifocal Retinopathy of Great Pyrenees. Vet Ophthalmol 1:211–221
  9. Grahn BH & Sandmeyer LS (2006) Multifocal retinopathy of Great Pyrenees dogs. Can Vet J 47(5):491-492
  10. Grahn BH & Cullen CL (2001) Retinopathy of Great Pyrenees dogs: fluorescein angiography, light microscopy and transmitting and scanning electron microscopy. Vet Ophthalmol 4(3):191-199
  11. Kenny PJ et al (2008) Retinopathy associated with ivermectin toxicosis in two dogs. J Am Vet Med Assoc 233(2):279-284