Breeds Affected: Maltese
Samples Accepted: Blood, Buccal Swabs
Disease Information: Glycogen Storage Disease Type Ia (GSD 1a) is a disease in which glycogen builds up in the body, particularly in the liver. Symptoms include enlarged liver, hyperglycemia, failure to thrive, and death.
Inheritance Information: GSD 1a 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/gsd1a The dog is a carrier, and can pass the allele on to approximately 50% of any offspring. If bred to another N/gsd1a carrier, approximately 25% of the offspring will be normal, 50% will be carriers, and 25% will be affected.
gsd1a/gsd1a The dog is affected, and should not be bred if it lives long enough to reproduce.
– Carriers may be bred to normal animals (N/gsd1a 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/gsd1a x N/gsd1a) is not recommended due to the possibility of 25% of the offspring being affected.
– If an affected animal (gsd1a/gsd1a) lives to reproductive age, it should not be bred.
Test Information: This mutation test identifies a single base change in the G6PC gene.
Kishnani, P.S., Bao, Y., Wu, J.Y., Brix, A.E., Lin, J.L., Chen, Y.T.: Isolation and nucleotide sequence of canine glucose-6-phosphatase mRNA: identification of mutation in puppies with glycogen storage disease type Ia. Biochem Mol Med 61:168-77, 1997. Pubmed reference: 9259982.
Further information is available at the Online Mendelian Inheritance in Animals website.