Polyneuropathy in Greyhounds

The Greyhound breed has been primarily bred for coursing game. Nowadays, the Greyhounds are mostly bred for professional racing and partly for exhibition purposes. Although both lines belong to the same breed, the breeds of show dogs and racing dogs have separated since 60-ties.

In the show line of Greyhounds, the polyneuropathy disease has been diagnosed having identical symptoms as the Charcot-Marie-Tooth (CMT) disease occurring in humans.

The polyneuropathy belongs to neurological diseases and the symptoms include decreased or absent reflexes, muscle weakness, muscle pain and cramps and an odd “bunny-hopping” gait, etc. Symptoms first appear clinically in young dogs at three to nine months of age and progress to the point where most affected dogs are euthanized within their first year. At present, there is no effective treatment that would sufficiently minder the worsening and painful symptoms.

It has been proven that the Polyneuropathy in Greyhounds is caused by a deletion of ten base pairs in NDRG1- gene in exon 15 (c.1080_1089delTCGCCTGGAC). This deletion causes a reading frame shift, which alters several amino acids before a stop codon is encountered. The NDRG1 gene is a member of the N-myc downregulated family which belongs to the alpha/beta hydrolase superfamily. The protein encoded by the NDRG1-gene is a cytoplasmic protein involved in stress responses, hormone responses, cell growth and differentiation. In affected individuals, there is no production of NDRG1-Protein and the symptoms of neuropathy appear (Drögemüller et al., 2010).

According to the survey made, the polyneuropathy is mostly spread in show dog population of greyhounds. 25% of the dogs tested were carriers of the mutation responsible for this disease (Drögemüller et al., 2010). In racing line of Greyhounds, the causal mutation has not been found yet. The breeders of the show dogs of Greyhounds should choose the individuals suitable for breeding with great care.

References:
Drögemüller C et al. A Deletion in the N-Myc Downstream Regulated Gene 1 (NDRG1)Gene in Greyhounds with Polyneuropathy PLoS One. 2010 Jun 22;5(6):e11258.