Hypomyelination (Weimaraner Type)

Other Names: Hypomyelination Syndrome, Shaky puppy syndrome, Spinal cord hypomyelination, Tremors, HS, HYM
Affected Genes: FNIP2
Inheritance: Autosomal Recessive
Mutation: chr15:55928287 (canFam3): 1 bp deletion (del A)

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Common Symptoms

Hypomyelination is an inherited neurologic disease affecting weimaraners. Affected dogs develop generalized tremors between 1 to 3 weeks of age. Affected puppies are able to walk but often have a hopping type of gait in the hind limbs. Tremors are not present when puppies are at rest or asleep, and there is often variation in severity even between affected littermates. Though the tremors typically improve by 3 to 4 months of age, severely affected puppies may be euthanized within the first few weeks of life. Additionally, a fine tremor of the hind limbs can persist as the dog ages.

Breed-Specific Information for the Weimaraner

The Mutation of the FNIP2 gene associated with hypomyelination has been identified in weimaraners, although its overall frequency in this breed is unknown.

Testing Tips

Genetic testing of the FNIP2 gene in weimaraners will reliably determine whether a dog is a genetic Carrier of hypomyelination. Hypomyelination is inherited in an Autosomal Recessive manner in dogs meaning that they 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 that is 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 FNIP2 gene mutation. Reliable genetic testing is important for determining breeding practices. In order to eliminate this mutation from breeding lines and to avoid the potential of producing affected pups, breeding of known carriers to each other is not recommended. Weimaraners that are not carriers of the mutation have no 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

  • Kornegay JN, Goodwin MA, Spyridakis LK. Hypomyelination in Weimaraner dogs. Acta Neuropathol. 1987;72(4):394-401. [PubMed: 3577694]
  • Millán Y, Mascort J, Blanco A, Costa C, Masian D, Guil-Luna S, Pumarola M, Martin de Las Mulas J. Hypomyelination in three Weimaraner dogs. J Small Anim Pract. 2010 Nov;51(11):594-8. [PubMed: 20973788]
  • Pemberton TJ, Choi S, Mayer JA, Li FY, Gokey N, Svaren J, Safra N, Bannasch DL, Sullivan K, Breuhaus B, Patel PI, Duncan ID. (2013) A mutation in the canine gene encoding folliculin-interacting protein 2 (FNIP2) associated with a unique disruption in spinal cord myelination. Glia 62:39-51. [PubMed: 24272703]