Canine degenerative myelopathy (DM) is a progressive neurodegenerative impairment of the spinal cord in many dog breeds. Usually clinical signs are not apparent in dogs younger than 8 years. DM is strongly correlated with a mutation c.118G>A in the superoxide-dismutase-1-gene (SOD1).

Numerous breeds including the Hovawart are known to be affected.

We report on statistical data regarding allele frequency of the mutation c.118G>A in the Hovawart breed in samples tested in the years 2009 to 2016.

Over 1500 samples of Hovawart dogs of any age were analysed. The mutant allele was present in the population at a frequency of 39,8%. This is concordant with published data. Forty point eight percent were heterozygous, respectively 19,4% were homozygous for the SOD1:c.118A genotype.

For an unbiased approach of monitoring frequency and age of disease onset in dogs with the homozygous high-risk genotype SOD1:c.118A we revised dogs above the age of 9 years which were under the age of 7 years at time of testing. Veterinary surgeons respectively breeders were asked to evaluate onset of disease and clinical signs.

Out of 13 dogs meeting the criteria 7 reports on health status were obtained. All 7 dogs showed clear symptoms of DM with onset at age 7 to 10 and a median of 8.5 years for this event. Out of these, 6 cases of DM were diagnosed by veterinarians. At the time of evaluation 6 out of 7 dogs were euthanized due to symptoms related to DM, all of them lacking post-mortem confirmation though. The median age of euthanizing was 9.5 years. Shortest interval between diagnosis and euthanasia was 2 months.

We conclude that the prevalence of developing symptoms of DM is strongly correlated with the homozygous genotype SOD1:c.118A in Hovawart dogs. Frequency of symptoms within the homozygous group may be higher than reported in random breed dogs earlier. Despite the limited number of cases, our data suggest that the homozygous genotype SOD1:c.118A displays extremely severe symptoms of DM in Hovawart dogs.

Disclosures

Disclosures to report.

All authors are employed at the diagnostic laboratory LABOKLIN GmbH & Co. KG.