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.

Genotypic and allelic frequency of a mutation in the NHEJ1 gene associated with collie eye anomaly in dogs in Italy.

BACKGROUND: A 7.8-kb deletion in intron 4 of the NHEJ1 canine gene is associated with Collie Eye Anomaly (CEA). This deletion has been described in sheep-herding breeds related to the collie lineage and in several other dog breeds. A genetic test based on this association can distinguish three genotypes: normal, carrier and affected. The present study is a retrospective investigation of the presence of the CEA allele frequencies in selected breeds from the Italian dog population over a 10-year time span. METHODS: Genotype data, for the 7.8 kb deletion in intron 4 of the NHEJ1 gene, from 496 dogs belonging to Border collie (BC, n = 334), Shetland Sheepdog (SS, n = 74), Australian Shepherd (AS, n = 52), Nova Scotia Duck Tolling Retriever (NS, n = 20) and Rough Collie (RC, n = 16) were analysed. The genetic frequency of CEA allele was estimated in breeds with higher observations (BC, SS and AS). RESULTS: Healthy carriers were 50%, 45%, 29.6%, 17.3% and 12.5% in SS, NS, BC, AS and RC, respectively. The affected recessive homozygotes were 81.3%, 10.8% and 1.5% in RC, SS and BC, respectively. The CEA allelic frequencies were 0.36, 0.16 and 0.087 in SS, BC and AS, respectively. CONCLUSION: The results support the usefulness of this type of genetic analysis to optimize the care of dogs where the CEA mutation is present, including assessing the health risk to susceptible dogs within a breed and to provide an objective basis for breeding programmes.