Description: Degenerative myelopathy in dogs is a serious neurodegenerative disease observed in many breeds of dogs. DM is a progressive disease that affects the white matter of the spinal cord. The average time of onset of clinical symptoms in a dog is 9 years, but there are significant differences between dogs. The primary image is hindlimb paralysis with progressive deterioration. Uncoordinated movement of the back of the body develops sensitivity and reflexes are impaired. As the disease progresses, the forelegs are also affected and the disease manifests as paresis and paralysis. The individual may eventually lose control of bladder and bowel function. In this disease, the individual does not suffer from pain, as there is a loss of spinal function due to myelin destruction and subsequent axonal degeneration causing progressive ataxia and paresis. As there is no cure, the disease can progress to the point where the animal is incontinent and possibly paraplegic. The affected animal is often euthanased for humane reasons.
DM is an autosomal recessive disease that exhibits variable penetration. Although the main genetic risk factor in dogs is a mutation within exon 2 of the SOD1 gene (c.118, G> A), it is thought that there are other genetic risk factors (modifying genes) depending on the dog’s breed that contribute to the earlier onset and disease progression. The SP110 gene encoding a nuclear protein that is involved in the regulation of gene expression and is part of the nuclear matrix has been described as a modifying gene.
Cardigan Welsh Corgi and Pembroke Welsh Corgi have a high mutation frequency of the mutation in the SOD1 gene (more than 30%). Homozygous individuals DM/DM for the mutation (a mutated allele is inherited from both parents) are susceptible to developing DM. However, not all Welsh Corgis of these Welsh Corgis will develop DM. Animals that are DM/DM fall into two groups: A. development of DM between the ages of 7 and 9; B. the disease does not develop until the age of 15. The SP110 modifying gene was identified in the Welsh Corgi breed, and mutations in the gene may increase the risk of developing DM and reduce the age of onset of degenerative myelopathy in DM/DM SOD1 Corgis. An increased risk of developing degenerative myelopathy was observed only in welsh corgi, not observed in other breeds.
In the absence of two copies of the common SOD1 mutation (c.118, G>A), this SP110 variant does not have any effect on a dog’s health. Dogs with one or two copies of the SP110 variant and without a mutation in SOD1 are not at increased risk for DM.
Inheritance: autosomal dominant
Mutation: SP110; chr.25:45,443,320, A>G, exon9
Sample: EDTA whole blood (1.0 ml) or 2 buccal brushes. For official purposes, the confirmation of the dog’s identity by a Veterinarian is recommended.
The analysis is suitable for the following breeds: Pembroke Welsh Corgi, Cardigan Welsh Corgi,
Notes: SP110 is a modifier and increases the risk of developing degenerative myelopathy in an autosomal dominant manner, which means that in dogs with the DM/DM genotype in the SOD1 gene, one allele with a mutation in SP110 is sufficient to expose them to an increased risk of developing DM. Animals with two copies of the SP110 mutation generally have more severe symptoms and an earlier onset of disease than animals with only one copy of the mutation.