Norfolk Terrier Pinboard

Tag: genetic test

  • Genetic test of Degenerative Myelophathy (DM) – useful for Norfolk Terriers?

    “The only situation where sod1 test results should be considered in making treatment and breeding decisions is when there are close relatives confirmed with clinical DM (and therefore a high probability of carrying other unidentified but necessary mutations for clinical disease).

    While the sod1 variant is the most frequent DNA variant identified in dogs, clinical degenerative myelopathy needs to be put back in the RARE and INFREQUENTLY DIAGNOSED category where it belongs.”

    Found on DogWellNet: DEGENERATIVE MYELOPATHY-DIAGNOSIS AND INHERITANCE by Jerold S Bell DVM, Dept. of Clinical Sciences, Tufts Cummings School of Veterinary Medicine, N. Grafton, MA USA

    Also see the post of Ann Milligan: Infographic – Quick Facts on Degenerative Myelopathy and Genetic Testing March 23, 2022:

    “The facts suggest that this test is not accurate enough to label dogs as at risk and certainly not for use in breed-wide strategies. In fact, the test has sometimes been promoted in breeds where there have never been confirmed cases and where there are more significant diseases and issues to be considered in healthy breeding.”

  • Asymptomatic macrothrombocytopenia in Norfolk and Cairn Terriers

    “An asymptomatic macrothrombocytopenia, phenotypically similar to asymptomatic inherited macrothrombocytopenia in Cavalier King Charles Spaniels, was described in a group of Norfolk Terriers (NT) from Northern Italy, and isolated cases were also reported in Cairn Terriers (CT). […]

    The β1-tubulin N-terminal amino acids form the nucleotide-binding domain and thus this mutation could affect GTP binding enough to influence platelet formation in homozygous but not in heterozygous dogs. The presence of macrothrombocytopenia only in homozygous affected dogs reveals an association between the SNP and the phenotype.”

    Maria Elena Gelain, Walter Bertazzolo, Giuseppina Tutino, Elena Pogliani, Francesco Cian, Mary K. Boudreaux: A novel point mutation in the β1-tubulin gene in asymptomatic macrothrombocytopenic Norfolk and Cairn Terriers.
    In: Veterinary Clinical Pathology: Volume 43, Issue 3. Pages:  305 – 472. September 2014.
    https://doi.org/10.1111/vcp.12168

  • Muscular dystrophy (DMD) found in a Norfolk Terrier – is it a problem in the breed?

    A six month old male Norfolk Terrier was confirmed as having dystrophin deficient muscular dystrophy (DD-MD) by the Animal Health Trust neurology department. The genetic cause of the disease in this dog could be identified by sequencing the coding exons of the dystrophin gene (DMD) of this dog and his mother, a novel variant in DMD was found causing the lack of functional dystrophin protein.

    In Norfolk Terriers the Dystrophin Deficient Muscular Dystrophy is caused by a defect of a gene on the X chromosome (X-linked recessive), therefore it is more likely that male dogs show signs of muscular dystrophy than female dogs because male dogs have only one copy of the X chromosome.

    Muscle cells without functional dystrophin are leaky, muscle health of all muscles is affected, no treatment for muscular dystrophy is available.

    Female dogs can be asymptomatic carriers of the dystrophin-deficient form of muscle dystrophy.

    A genetic test is available.

    Jenkins, C.A., Forman, O.P. Identification of a novel frameshift mutation in the DMD gene as the cause of muscular dystrophy in a Norfolk terrier dog. Canine Genet Epidemiol 2, 7 (2015). https://doi.org/10.1186/s40575-015-0019-4

    Sánchez L, Beltrán E, de Stefani A, Guo LT, Shea A, Shelton GD, et al. (2018) Clinical and genetic characterisation of dystrophin-deficient muscular dystrophy in a family of Miniature Poodle dogs. PLoS ONE 13(2): e0193372. https://doi.org/10.1371/journal.pone.0193372

    Malcolm Weir, DVM, MSc, MPH; Catherine Barnette, DVM: Muscular Dystrophy.

    Shelton, G.D.; Minor, K.M.; Friedenberg, S.G.; Cullen, J.N.; Guo, L.T.; Mickelson, J.R. Current Classification of Canine Muscular Dystrophies and Identification of New Variants. Genes 2023, 14, 1557. https://doi.org/10.3390/genes14081557