Progressive Retinal Atrophy, Syndromic Retinal Degeneration (Shetland Sheepdog Type)
Affected Genes: BBS2
Inheritance: Autosomal Recessive
Variant(canFam6):
chr2:56327428: G>C
Breed: Shetland Sheepdog
General Information: Progressive Retinal Atrophy, Syndromic Retinal Degeneration (Shetland Sheepdog Type) is an inherited eye disease in dogs that typically manifests between 6 to 10 years of age with initial signs seen during veterinary eye exams as changes in the Tapetum's reflectivity. As the disease progresses, there is thinning of retinal blood vessels, leading to diminished blood flow and subsequent vision loss, starting with night blindness and peripheral vision impairment, potentially progressing to total blindness. Affected dogs may also exhibit a variety of other clinical signs such as an upturned nose, dental abnormalities, coat anomalies, kidney issues, and obesity, albeit the severity and combination of these symptoms vary among individuals.
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 BBS2 gene identifies whether a dog carries Progressive Retinal Atrophy, Syndromic Retinal Degeneration (Shetland Sheepdog Type). This disease follows an Autosomal Recessive inheritance pattern, requiring both parents to pass on a mutated gene for a dog to develop symptoms. Carriers typically show no signs of the disease but mating two carriers increases the risk of affected offspring. Reliable testing informs breeding decisions to prevent producing affected puppies, although a normal BBS2 result doesn't rule out other forms of progressive retinal atrophy caused by different gene mutations within the pedigree.
References:
Hitti-Malin RJ, Burmeister LM, Lingaas F, Kaukonen M, Pettinen I, Lohi H, Sargan D, Mellersh CS. A Missense Variant in the Bardet-Biedl Syndrome 2 Gene (BBS2) Leads to a Novel Syndromic Retinal Degeneration in the Shetland Sheepdog. Genes (Basel) 2021 12(11):1771.