Greyhound polyneuropathy

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Wallerian degeneration and deficit in myelinated alpha fibres in an affected dog (left) compard with a normal greyhound.[1]

Greyhound polyneuropathy is a Greyhound-specific autosomal-recessive genetic polyneuropathy characterized by muscle weakness.

This disease occurs as a result of a severe chronic progressive mixed polyaxonal neuropathy due to missense mutation in the NDRG1 gene. This disease is similar to recessive inherited human Charcot-Marie-Tooth disease[2].

In this disease, greyhounds present at 6 - 9 months of age with generalized muscle weakness, exercise intolerance, a high stepping or 'bunny-hopping' gait in the early stages of disease that progresses to severe muscle atrophy, ataxia and dysphonia due to proprioceptive deficits and laryngeal involvement.

Symptoms first appear at three to nine months of age and progress to the point where most affected dogs are euthanized within their first year.

A tentative diagnosis can be established by presenting clinical signs, electromyographs and histological examination of muscle tissue.

Definitive diagnosis requires DNA testing of affected dogs and progeny testing of at-risk dogs.

There is no known treatment for this condition.

References

  1. Drögemüller C et al (2010) A Deletion in the N-Myc Downstream Regulated Gene 1 (NDRG1)Gene in Greyhounds with Polyneuropathy PLoS One. 5(6):e11258
  2. Kalaydjieva L et al (2000) N-myc downstream-regulated gene 1 is mutated in hereditary motor and sensory neuropathy-Lom. Am J Hum Genet 67:47–58