Breeds Affected: Yorkshire Terrier
Samples Accepted: Blood, Buccal Swabs
Disease Information: L-2-Hydroxyglutaric aciduria (L-2-HGA) is characterized by affected animals having seizures, difficulty walking due to uncoordinated movement, and/or behaviour changes such as sudden hyperactivity, sudden aggression, or dementia. Affected dogs normally show symptoms between 6-12 months of age.
Inheritance Information: L-2-HGA 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/hga The dog is a carrier, and can pass the allele on to approximately 50% of any offspring. If bred to another N/hga carrier, approximately 25% of the offspring will be normal, 50% will be carriers, and 25% will be affected.
hga/hga The dog is affected. If bred to a normal animal, 100% of the offspring will be carriers. If bred to an N/hga carrier, 50% of the offspring will be carriers and 50% will be affected.
– Carriers may be bred to normal animals (N/hga 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/hga x N/hga) is not recommended due to the possibility of 25% of the offspring being affected.
– Affected animals (hga/hga) should not be used for breeding.
Test Information: This mutation test identifies a single base change in the L2HGDH gene.
Farias, F.H., Zeng, R., Johnson, G.S., Shelton, G.D., Paquette, D., O’Brien, D.P.: A L2HGDH initiator methionine codon mutation in a Yorkshire terrier with L-2-hydroxyglutaric aciduria. BMC Vet Res 8:124, 2012. Pubmed reference: 22834903. DOI: 10.1186/1746-6148-8-124.
Further information is available at the Online Mendelian Inheritance in Animals website.