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Degenerative Myelopathy (Bernese Mountain Dog Variant)

Degenerative Myelopathy (DM) in Bernese Mountain Dogs, caused by a mutation in the SOD1 gene, is a progressive neurological disorder leading to muscle atrophy and loss of coordination, especially in the hind limbs.

Affected Genes: SOD1

Inheritance: Autosomal Recessive

Variant(canFam6):
chr31:26647433: A>T

Breed: Bernedoodle
Bernese Mountain Dog

General Information: Degenerative Myelopathy (DM) SOD1B in Bernese Mountain Dogs is a hereditary neurological disorder characterized by a slow progression of symptoms due to a mutation in the SOD1 gene, specifically identified in this breed. The disease typically manifests in dogs around nine years of age and affects the white matter tissue of the spinal cord, which is essential for nerve signal transmission. Dogs with DM present with gradual muscle atrophy and loss of coordination, particularly starting in the hind limbs. This degeneration leads to difficulty in walking, and as the disease progresses, dogs may lose the ability to walk entirely and eventually experience incontinence and forelimb weakness. The condition is similar to amyotrophic lateral sclerosis (ALS) in humans and is not usually painful. Due to the debilitating nature of DM, affected medium to large breed dogs, like the Bernese Mountain Dog, often require significant care, and owners may elect euthanasia when mobility becomes severely impaired. Managing the disease requires careful attention to the dog's quality of life as symptoms progressively worsen over time.

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 for the SOD1 gene is critical for identifying carriers of the SOD1B mutation associated with Degenerative Myelopathy (DM) in Bernese Mountain Dogs. This disorder is inherited in an autosomal recessive manner, meaning a dog must inherit two copies of the mutated gene, one from each parent, to develop the disease. Dogs carrying only one copy of the mutation (carriers) typically do not show symptoms but can pass the gene to their offspring. When two carriers are bred, each puppy has a 25% chance of developing DM and a 50% chance of being a carrier. Reliable genetic testing is essential for responsible breeding practices to avoid mating two carriers, thus reducing the risk of producing puppies that will develop DM. Testing helps breeders make informed decisions to maintain the health and integrity of their breeding lines by eliminating this mutation from future generations. It is important to note that while genetic testing is crucial for detecting the risk of DM, the disease's progression can be influenced by various genetic and environmental factors, necessitating comprehensive care and monitoring for at-risk dogs.

References:
Awano T, Johnson GS, Wade CM, Katz ML, Johnson GC, Taylor JF, Perloski M, Biagi T, Baranowska I, Long S, March PA, Olby NJ, Shelton GD, Khan S, O'Brien DP, Lindblad-Toh K, Coates JR. Genome-wide association analysis reveals a SOD1 mutation in canine degenerative myelopathy that resembles amyotrophic lateral sclerosis. Proc Natl Acad Sci USA. 2009 106(8):2794-2799.

Coates JR, Wininger FA. Canine degenerative myelopathy. Vet Clin North Am Small Anim Pract. 2010 40(5):929-950.

Pfahler S, Bachmann N, Fechler C, Lempp C, Baumgärtner W, Distl O. Degenerative myelopathy in a SOD1 compound heterozygous Bernese mountain dog. Anim Genet. 2014 45(2):309-310.