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Neuroaxonal Dystrophy (NAD) - Giant Schnauzer-Beagle Type
| Acronym: | NAD |
| Gene: | MFN2 |
| Mutation: | g.84289961_84289959del |
| Inheritance: | Autosomal Recessive |
| Sample type: | CHS (Cheek Swab), WBE (Whole Blood EDTA) |
Genetics and characteristics
Neuroaxonal Dystrophy (NAD) is part of a group of genetic degenerative neurological diseases characterized by dystrophic changes in the neurons. NADs in animals have been reported in several animals including dogs. The disease shows young adult age of onset with the mild progression of clinical signs that typically include postural deficits, ataxia, hypermetria, and tremor. This type of neuroaxonal dystrophy is specific to Giant Schnauzer-Beagle crossbreed dogs and it is caused by a 3-nucleotide deletion in the mitofusin 2 (MFN2) gene. MFN2 helps determine the shape and structure (morphology) of mitochondria, the energy-producing centers within cells and it can be found in cell types and tissues, including muscles, the spinal cord, and the nerves that connect the brain and spinal cord to sensory cells.
This type of degenerative neurological disease that affects Giant Schnauzer-Beagle crossbreed dogs is inherited as an autosomal recessive trait meaning two copies of the mutated gene are required for the disease to develop. That means dogs with only one copy of the mutated MFN2 gene will not develop the disease but can act as carriers of the mutation. Early genetic testing can help identify affected dogs that carry the mutation and prevent their further breeding by proper selection of mating pairs.
Results Reported As
Test Result |
Interpretation of test result |
CLEAR |
Tested mutation was not detected in animal with „clear“ result. Animal tested as clear has wild-type allele in homozygous state (i.e. two pairs of healthy alleles). It will not develop disease caused by tested mutation.* It will pass only wild-type allele to its offspring. |
CARRIER |
Tested mutation was detected in animal with „carrier“ result. Animal tested as carrier has one wild-type and one mutation allele, it is in heterozygous state. It will not develop disease caused by tested mutation.* It can pass wild-type or mutation allele to its offspring. |
AFFECTED |
Tested mutation was detected in animal with „affected“ result. Animal tested as affected has two copies of mutation alleles affecting the gene. It is likely the animal will experience a genetic disorder due to this mutation.** It will pass only mutation allele to its offspring. |
*Test excludes only tested mutation but not possible unknown mutations or factors that can lead to similar condition/symptoms.
** Potential unknown mutations or multiple other factors can possibly affect the likelihood of experiencing a genetic disorder.
References:
Fyfe, J. C., Al-Tamimi, R. A., Liu, J., Schäffer, A. A., Agarwala, R., Henthorn, P. S. (2011). A novel mitofusin 2 mutation causes canine fetal-onset neuroaxonal dystrophy. Neurogenetics, 12(3), 223–232. https://doi.org/10.1007/s10048-011-0285-6
Fyfe, J. C., Al-Tamimi, R. A., Castellani, R. J., Rosenstein, D., Goldowitz, D., Henthorn, P. S. (2010). Inherited neuroaxonal dystrophy in dogs causing lethal, fetal-onset motor system dysfunction and cerebellar hypoplasia. The Journal of comparative neurology, 518(18), 3771–3784. https://doi.org/10.1002/cne.22423