Charcot-Marie-Tooth Disease

Affected Genes: MTMR13
Inheritance: Autosomal Recessive
Mutation: chr21:33682425 (canFam4): C/A
Breed(s): Miniature Schnauzer

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Common Symptoms

Charcot-Marie-Tooth Disease is an inherited neurological disease affecting dogs. Affected dogs typically present before 2 years of age with clinical signs related to megaesophagus and laryngeal paralysis. These include regurgitation, abnormal vocalization or quiet barking, and difficult, loud breathing. Less often dogs may have mild neurological abnormalities including delayed reflexes, tremors, hind end weakness, or exercise intolerance. This condition is slowly progressive and affected dogs may live normal lifespans with management of clinical signs.

Testing Tips

Genetic testing of the SBF2/MTMR13 gene in dogs will reliably determine whether it is a genetic Carrier of Charcot-Marie-Tooth Disease. This disease is inherited in an Autosomal Recessive manner. This means that dogs must receive two copies of the mutated gene (one from each parent) to develop the disease. In general, carrier dogs do not have features of the disease but when bred with another carrier of the same Mutation, there is a risk of having affected pups. Each pup born to this pairing has a 25% chance of inheriting the disease and a 50% chance of inheriting one copy and being a carrier of the SBF2/MTMR13 gene mutation. Reliable genetic testing is important for determining breeding practices. To eliminate this mutation from breeding lines and avoid the potential of producing affected pups, breeding of known carriers to each other is not recommended. Dogs that do not carry the mutation are not at increased risk of having affected pups.

There may be other causes of this condition in dogs and a normal result does not exclude a different mutation in this gene or any other gene that may result in a similar genetic disease or trait.

References

  • Farré Mariné, A, Granger, N, Bertolani, C, Mascort Boixeda, J, Shelton, GD, Luján Feliu-Pascual, A. Long-term outcome of Miniature Schnauzers with genetically confirmed demyelinating polyneuropathy: 12 cases. J Vet Intern Med. 2020; 34:2005-2011. [PubMed: 32738000]
  • Granger N, Luján Feliu-Pascual A, Spicer C, Ricketts S, Hitti R, Forman O, Hersheson J, Houlden H. 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. 2019 Nov 21;7: e7983 [PubMed: 31772832]