Molecular Epidemiological Survey for Degenerative Myelopathy in German Shepherd Dogs in Japan: Allele Frequency and Clinical Progression Rate

Genotypic and Allelic Frequencies of Degenerative Myelopathy in an Italian Canine Population

Canine degenerative myelopathy is a fatal neurodegenerative disorder that affects the spinal cord. It is a late-onset disease, with symptoms becoming evident later in life at approximately 8 years of age. The principal aim of this study was to retrospectively evaluate allelic and genotypic frequencies of the c.118G > A and c.52A > T mutations located on the SOD1 gene in an Italian canine population to provide detailed information on the prevalence of the mutations in the country. The genetic data of different breeds were collected through DNA tests over a nine-year period in the Italian canine population. For each dog, the breed, sex, age, and DNA test results were recorded. Allelic and genotypic frequencies were calculated. A total of 1667 DNA tests for the c.118G > A and c.52A > T mutations were carried out on 84 breeds. For the analysis of prevalence, only breeds counting more than 20 subjects have been considered, for a total of 1410 DNA tests obtained from 13 different breeds. In the population tested for the c.118G > A mutation, 65.47% (n. 893) of the subjects were clear, 25.59% (n. 349) were heterozygous carriers, and 8.94% (n. 122) were homozygous for the mutated allele. The mutation showed the highest frequency in Pembroke Welsh Corgis (55.49%) and the lowest frequencies in Poodles (6.32%) and Australian Shepherds (7.14%). The allelic frequency of the c.52A > T mutation was 7.61% in the Bernese Mountain dog. Neither variant differed between females and males in genotypic frequencies. The present study provides insights into the allelic and genotypic frequencies of canine degenerative myelopathy in different dog breeds in Italy.

Common Neurologic Diseases in Geriatric Dogs

The increase in the canine geriatric population means that veterinarians are more often confronted with diseases that are more prevalent in patients in this age group. As in other organ systems, degenerative, neoplastic, and vascular diseases are the most prevalent neurologic disorders in older dogs. A neurological disease in an older dog poses a challenge for the clinician due to the presence of concomitant diseases and age-related changes that make it difficult to interpret the neurological examination. In addition, given the age of the patients, some owners do not allow advanced imaging tests, and it is necessary to establish the most likely presumptive diagnosis to initiate treatment. Although many of these diseases can cause clinical signs that can be very upsetting, some of them can be managed with symptomatic therapy and have a good prognosis, such as idiopathic vestibular syndrome. Moreover, advances in and the greater availability of therapeutic options such as surgery and radiation therapy may increase survival and quality of life in diseases with a more serious prognosis, such as tumours. The aim of this review is to summarize the clinical presentation, diagnosis, and treatment of the more frequent diseases affecting the central nervous systems of geriatric dogs.

Allele and genotype frequencies for primary hereditary cataract, multifocal retinopathy 1, and degenerative myelopathy in Pyrenean Mountain dog from Italy

Pyrenean Mountain Dog (PMD) is an ancient dog breed firstly described in XIV century in the Pyrenees Region and nowadays diffused both in Europe and in the US. Hereditary Cataract (HC), defined as the inherited opacity of the lens, involves clinical signs ranging from reduced vision to glaucoma. A molecular basis of HC was firstly described in Staffordshire Bull Terriers and then reported in multiple canine breeds. The HC-associated variation is a single nucleotide deletion in HSF4 gene that introduces a premature stop codon (c.962del, p.Ala321*). Multifocal Retinopathy 1 (MR) is an ocular disorder characterized by multiple areas of retinal degeneration, caused in various dog breeds (including PMD) by a single nucleotide variant (SNV) in BEST1 gene that generates a premature stop codon (c.73G>A, p.Arg25*). Degenerative Myelopathy (DM) is an adult-onset, progressive neurodegenerative disease and it is associated to a SNV in SOD1 gene causing a change in aminoacidic sequence of the protein (c.118G>A, p.Glu40Lys). This causative variant has been described in various dog breeds, including PMD. Aim of this study was to determine the allele frequencies for the abovementioned three genetic diseases in the Italian breeding PMD population. The survey found no dogs carrying the allele (deletion) associated with HC, while three dogs (6 %) were heterozygous (G/A) for the MR-associated variant, and seven dogs (13 %) were heterozygous (G/A) for the DM-associated alteration, indicating that the variant alleles frequency were 0  %, 3 %, and 7 %, respectively. Appropriate mating management is suggested for the prevention of genetic diseases spreading in the PMD population.

Molecular Surveillance of Canine Degenerative Myelopathy in Breeding Kennels from Romania

Canine degenerative myelopathy (CDM) is a spontaneous neurodegenerative disease. Genetically, CDM is an autosomal recessive disease with incomplete penetrance, most commonly caused by a genetic mutation in exon 2 of gene SOD1 (c.118G > A). This study aimed to determine the mutant allele frequency associated with CDM in various dog breeds from Romania. Dogs (n = 230) from 26 breeds were included in the study. Genotyping using the PCR-RFLP technique was performed on DNA extracted from oral swabs. The results revealed that 204 dogs were homozygous for the wild-type allele (G/G), 16 were heterozygous (A/G), and 10 were homozygous for the mutant allele (A/A). The mutant allele was identified in Wire Fox Terrier, Romanian Mioritic Shepherd, German Shepherd, Rottweiler, Belgian Shepherd, and Czechoslovakian Wolfdog breeds. The mutant allele frequency (A) within the tested population was 0.0783. The results for Belgian Shepherd, German Shepherd, and Romanian Mioritic Shepherd were in Hardy-Weinberg equilibrium, but a departure was observed for Rottweiler. The current study included a first screening of the Romanian Bucovina Shepherd, Romanian Mioritic Shepherd, and Caucasian Shepherd breeds. Genetic testing for the mutation associated with CDM is important in order to avoid the risk of the emergence of dogs homozygous for the SOD1:c118G > A allele.