Breeds Affected: Coton de Tulear
Samples Accepted: Blood, Buccal Swab
Disease Information: Also known as “Bandera Neonatal Ataxia (BNAt)”, is a problem with the function of the cerebellum. When normal pups begin to walk, affected pups are unable to do so, falling over if they are able to even stand. Tremors may be visible in the eye, although vision seems to be mostly normal. Affected pups have a very poor quality of life and are usually humanely euthanized before 4 months of age.
Inheritance Information: BNAt is autosomal recessive, meaning that animals with two copies of this allele will be affected. Animals with one copy of the gene will be clinically-normal carriers.
The possible genotypes are:
N/N The dog is normal, and cannot produce affected offspring.
N/bnat The dog is a carrier, and can pass the allele on to approximately 50% of any offspring. If bred to another N/bnat carrier, approximately 25% of the offspring will be normal, 50% will be carriers, and 25% will be affected.
bnat/bnat The dog is affected. If bred to a normal animal, 100% of the offspring will be carriers. If bred to an N/igs carrier, 50% of the offspring will be carriers and 50% will be affected.
– Carriers may be bred to normal animals (N/bnat x N/N) without any risk of producing affected offspring. The offspring should be tested before breeding to determine if they are carriers or normal.
– Breeding two carriers (N/bnat x N/bnat) is not recommended due to the possibility of 25% of the offspring being affected.
– Affected animals (bnat/bnat) should not be used for breeding.
Test information: This mutation test identifies an insertion in exon 8 of the GRM1 gene.
Zeng, R., Farias, FH., Johnson, GS., McKay, SD., Schnabel, RD., Decker, JE., Taylor, JF., Mann, CS., Katz, ML., Johnson, GC., Coates, JR., O’Brien, DP.: A truncated retrotransposon disrupts the GRM1 coding sequence in Coton de Tulear dogs with Bandera’s neonatal ataxia. J Vet Intern Med 25:267-72, 2011. Pubmed reference: 21281350. DOI: 10.1111/j.1939-1676.2010.0666.x
Further information is available at the Online Mendelian Inheritance in Animals website.