Stargardt Disease (STGD Dog)
Stargardt disease (STGD) is an eye disease in which affected dogs show impaired vision. Due to a mutation in the gene for a membrane transporter protein in the photoreceptor cells (cones and rods), lipofuscin ("age pigment") is deposited in the retinal pigment epithelium (RPE) of the retina and the photoreceptor cells slowly degenerate.
The disease occurs in the Labrador Retriever and the inheritance is autosomal recessive.
Synonym: STGD-PRA, Morbus Stargardt
Genetic Test: available in Shop
Symptoms
- Impairment of vision
- Widened pupils in daylight
- Abnormal pupillary light and glare reflexes
- Excessive growth in the retinal pigment epithelium (RPE)
- Low visual ability persists in old age
General Information
- Stargardt disease (STGD) is an eye disease caused by an altered membrane transporter protein in the photoreceptor cells (cones and rods).
- This leads to the storage of lipofuscin ("age pigment") in the retinal pigment epithelium (RPE) of the retina.
- The photoreceptor cells responsible for vision die, the cones (day and colour vision) are affected earlier than those of the rods (dim light vision).
- Some rod cells remain intact even into old age.
Breeds affected
Labrador Retriever
Test Information
Genotype and Lab Report
Inheritance: autosomal recessive
→ The disease only occurs when both alleles of the gene are affected by the mutation (stgd/stgd). Dogs that have only one allele with the causative mutation (N/stgd) are clinically healthy carriers.
Genotypes:
N/N = genetically normal
The dog has no variants for STGD and thus cannot pass it on to offspring.
N/stgd = a carrier
The dog is a clinically healthy carrier. The variation is passed on 50% to the offspring, which are also carriers.
stgd/stgd = affected
The variation will be passed on to 100% to the offspring. The offspring are carriers or affected.
Recommendations
- Carrier animals can be bred to normal animals (N/stgd x N/N). Before using the offspring in breeding, it should be tested whether they are normal or carriers.
- Mating two carrier animals (N/stgd x N/stgd) should be avoided because there is a 25% chance that the offspring will be affected.
- Affected animals (stgd/stgd) should be excluded from breeding.
Literature
Mäkeläinen, S., Gòdia, M., Hellsand, M., Viluma, A., Hahn, D., Makdoumi, K., Zeiss, C.J., Mellersh, C., Ricketts, S.L., Narfström, K., Hallböök, F., Ekesten, B., Andersson, G., Bergström, T.F.: An ABCA4 loss-of-function mutation causes a canine form of Stargardt disease. PLoS Genet 15:e1007873, 2019. Pubmed reference: 30889179. DOI: 10.1371/journal.pgen.1007873.
Zangerl, B., Lindauer, S.J., Acland, G.M., Aguirre, G.D.: Identification of genetic variation and haplotype structure of the canine ABCA4 gene for retinal disease association studies. Mol Genet Genomics 284:243-50, 2010. Pubmed reference: 20661590.
Further information is available at: Online Mendelian Inheritance in Animals.