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Progressive retinal atrophy (PRA-MS, PRA1, PRA-B1, HIVEP3) - Miniature Schnauzer Type
| Acronym: | B1PRA, HIVEP3 |
| Gene: | HIVEP3 |
| Mutation: | g.1432293G>A |
| Inheritance: | Autosomal Recessive |
| Sample type: | CHS (Cheek Swab), WBE (Whole Blood EDTA) |
Genetics and characteristics
Progressive Retinal Atrophy (PRA) is a genetic eye disorder, which belongs to blinding retinal degenerative diseases. Different types of retinal atrophies have been detected in different dog breeds so far, even within the same breed. Type B1 PRA is one of two types of retinal atrophy disorders that are found in Miniature Schnauzer dogs differing in the age of onset and pattern of disease progression. B1 causes an early onset form of the disease and is characterized by degeneration of retinal photoreceptor cells leading to progressive degeneration in peripheral and central areas of the eye causing night blindness and progressive vision loss in affected dogs. It is caused by the mutation in the HIVEP3 gene that encodes a protein that acts as a transcription factor and is important for the transcription of other proteins. The mutation in HIVEP3 results in overexpression of two retinal target genes, EDN2 and COL9A2, and leads to degeneration of retina photoreceptors.
This retinal atrophy disorder in Miniature Schnauzer is inherited as an autosomal recessive trait, requiring two copies of the mutated gene for the disease to develop. Dogs with only one copy of the mutated gene will not develop the disease but may act as carriers and pass the mutation to their offspring. There is no cure for B1 PRA, and the only way to prevent it is early detection by genetic testing that can help breeders in selecting future mating pairs.
Results Reported As
Test Result |
Interpretation of test result |
CLEAR |
Tested mutation was not detected in animal with „clear“ result. Animal tested as clear has wild-type allele in homozygous state (i.e. two pairs of healthy alleles). It will not develop disease caused by tested mutation.* It will pass only wild-type allele to its offspring. |
CARRIER |
Tested mutation was detected in animal with „carrier“ result. Animal tested as carrier has one wild-type and one mutation allele, it is in heterozygous state. It will not develop disease caused by tested mutation.* It can pass wild-type or mutation allele to its offspring. |
AFFECTED |
Tested mutation was detected in animal with „affected“ result. Animal tested as affected has two copies of mutation alleles affecting the gene. It is likely the animal will experience a genetic disorder due to this mutation.** It will pass only mutation allele to its offspring. |
*Test excludes only tested mutation but not possible unknown mutations or factors that can lead to similar condition/symptoms.
** Potential unknown mutations or multiple other factors can possibly affect the likelihood of experiencing a genetic disorder.
References:
Kaukonen, M., Quintero, I. B., Mukarram, A. K., Hytönen, M. K., Holopainen, S., Wickström, K., Kyöstilä, K., Arumilli, M., Jalomäki, S., Daub, C. O., Kere, J., Lohi, H., DoGA Consortium (2020). A putative silencer variant in a spontaneous canine model of retinitis pigmentosa. PLoS genetics, 16(3), e1008659. https://doi.org/10.1371/journal.pgen.1008659
Jeong, M. B., Park, S. A., Kim, S. E., Park, Y. W., Narfström, K., Seo, K. (2013). Clinical and electroretinographic findings of progressive retinal atrophy in miniature schnauzer dogs of South Korea. The Journal of veterinary medical science, 75(10), 1303–1308. https://doi.org/10.1292/jvms.12-0358