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Charcot-Marie-Tooth Neuropathy (CMT)
| Acronym: | CMT |
| Gene: | SBF2 (MTMR13) |
| Mutation: | c.2363+1G>T |
| Inheritance: | Autosomal Recessive |
| Sample type: | CHS (Cheek Swab), WBE (Whole Blood EDTA) |
Genetics and characteristics
Charcot-Marie-Tooth Neuropathy (CMT) is a group of inherited conditions that affect motor, sensory or autonomic peripheral nerves. CMT is the most common neuromuscular disorder in humans, but its homologs have been identified in other animals including dogs. In dogs, CMT is known as polyneuropathy, the condition with an onset at around 2 years of age causing affected dogs to lose balance and ability to support their weight, and respiratory difficulties such as laryngeal paralysis which often leads to euthanasia. The type of CMT that affects Miniature Schnauzer dogs is caused by a genetic variant of the MTRM13/SBF2. The SBF2 (SET-binding factor 2), also known as the MTMR13 (myotubularin-related protein-13) gene, encodes for a pseudophosphatase which has a role in regulating vesicular trafficking in Schwann cells, one type of glial cells.
This type of neuromuscular condition in dogs is inherited as an autosomal recessive trait meaning two copies of the mutated gene are required for the disease to develop. Dogs with only one copy of the mutated gene will not develop the disease but act as carriers that can potentially pass the mutation to their offspring. Early detection by genetic testing can identify carriers and inform the breeders decision when selecting mating pairs. This can be used to avoid the unintentional breeding of affected puppies.
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:
Granger, N., Luján Feliu-Pascual, A., Spicer, C., Ricketts, S., Hitti, R., Forman, O., Hersheson, J., Houlden, H. (2019). Charcot-Marie-Tooth type 4B2 demyelinating neuropathy in miniature Schnauzer dogs caused by a novel splicing SBF2 (MTMR13) genetic variant: a new spontaneous clinical model. PeerJ, 7, e7983. https://doi.org/10.7717/peerj.7983
Farré Mariné, A., Granger, N., Bertolani, C., Mascort Boixeda, J., Shelton, G. D., Luján Feliu-Pascual, A. (2020). Long-term outcome of Miniature Schnauzers with genetically confirmed demyelinating polyneuropathy: 12 cases. Journal of veterinary internal medicine, 34(5), 2005–2011. https://doi.org/10.1111/jvim.15861