Breeds Affected: Portuguese Water Dog
Samples Accepted: Blood, Buccal Swabs
Disease Information: GM1 Gangliosidosis (GM1-G) is a fatal lysosomal storage disease. Affected Portuguese Water Dogs show progressive neurologic impairment leading to signs of cerebellar dysfunction between 5-6 months of age.
Inheritance Information: GM1-G 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/gm1g The dog is a carrier, and can pass the allele on to approximately 50% of any offspring. If bred to another N/gm1g carrier, approximately 25% of the offspring will be normal, 50% will be carriers, and 25% will be affected.
gm1g/gm1g The dog is affected, and will not live long enough to reproduce.
– Carriers may be bred to normal animals (N/gm1g 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/gm1g x N/gm1g) is not recommended due to the possibility of 25% of the offspring being affected.
Test Information: This mutation test identifies a single base change in exon 2 of the GLB1 gene.
Wang, Z.H., Zeng, B., Shibuya, H., Johnson, G.S., Alroy, J., Pastores, G.M., Raghavan, S., Kolodny, E.H.: Isolation and characterization of the normal canine beta-galactosidase gene and its mutation in a dog model of GM1-gangliosidosis. J Inherit Metab Dis 23:593-606, 2000. Pubmed reference: 11032334
Further information is available at the Online Mendelian Inheritance in Animals website.