GM1 Gangliosidosis (Shiba Inu Type)

Common Symptoms

GM1 gangliosidosis (shiba inu type) is an inherited Lysosomal Storage Disorder affecting shiba inu dogs. Affected dogs typically present with symptoms of neurologic disease around 5 to 6 months of age. Dogs with GM1 gangliosidosis have insufficient activity of the Enzyme beta-galactosidase, which is responsible for breaking down specific carbohydrates in the cells. As a result, there is an accumulation of break down products such as GM1 in cells, especially cells of the brain and nervous system. Symptoms include vision loss, difficulties walking, loss of balance, head tremors, lethargy and weight loss. By 9 to 12 months of age affected dogs are lethargic, have cloudy corneas, and may have involuntary muscle contractions. Dogs usually die by 15 months of age.

Breed-Specific Information for the Shiba Inu

The Mutation of the GLB1 gene associated with GM1 gangliosidosis (shiba inu type) has been identified in the shiba inu. Though the exact frequency in the overall Shiba Inu population is unknown, 2.9% out of 68 shiba inu from northern Japan and 1.0% out of 590 from throughout Japan were carriers of the mutation.

Testing Tips

Genetic testing of the GLB1 gene in shiba inu will reliably determine whether a dog is a genetic Carrier of GM1 gangliosidosis (shiba inu type). GM1 gangliosidosis (shiba inu type) is inherited in an Autosomal Recessive manner in dogs meaning that they must receive two copies of the mutated gene (one from each parent) to develop the disease. In general, carrier dogs do not have features of the disease but when bred with another carrier of the same Mutation, there is a risk of having affected pups. Each pup that is born to this pairing has a 25% chance of inheriting the disease and a 50% chance of inheriting one copy and being a carrier of the GLB1 gene mutation. Reliable genetic testing is important for determining breeding practices. In order to eliminate this mutation from breeding lines and to avoid the potential of producing affected pups, breeding of known carriers to each other is not recommended. Shiba inu that are not carriers of the mutation have no increased risk of having affected pups.

There may be other causes of this condition in dogs and a normal result does not exclude a different mutation in this gene or any other gene that may result in a similar genetic disease or trait.

References

• Chang HS, Arai T, Yabuki A, Hossain MA, Rahman MM, Mizukami K, Yamato O. Rapid and reliable genotyping technique for GM1 gangliosidosis in Shiba dogs by real-time polymerase chain reaction with TaqMan minor groove binder probes. J Vet Diagn Invest. 2010 Mar; 22(2):234-7. [PubMed: 20224082]
• Uddin MM, Arata S, Takeuchi Y, Chang H, Mizukami K, Yabuki A, Rahman MM, Kohyama M, Hossain MA, Takayama K, Yamato O. Molecular epidemiology of canine GM1 gangliosidosis in the Shiba Inu breed in Japan: relationship between regional prevalence and carrier frequency. BMC Vet Res. 2013 Jul 3;9:132. [PubMed: 23819787]
• Yamato O, Endoh D, Kobayashi A, Masuoka Y, Yonemura M, Hatakeyama A, Satoh H, Tajima M, Yamasaki M, Maede Y. A novel mutation in the gene for canine acid beta-galactosidase that causes GM1-gangliosidosis in Shiba dogs. J Inherit Metab Dis. 2002 Oct; 25(6):525-6. [PubMed: 12555949]
• Yamato O, Jo EO, Chang HS, Satoh H, Shoda T, Sato R, Uechi M, Kawasaki N, Naito Y, Yamasaki M, Maede Y, Arai T. Molecular screening of canine GM1 gangliosidosis using blood smear specimens after prolonged storage: detection of carriers among shiba dogs in northern Japan. J Vet Diagn Invest. 2008 Jan; 20(1):68-71. [PubMed: 18182512]
• Yamato O, Masuoka Y, Yonemura M, Hatakeyama A, Satoh H, Kobayashi A, Nakayama M, Asano T, Shoda T, Yamasaki M, Ochiai K, Umemura T, Maede Y. Clinical and clinico-pathologic characteristics of Shiba dogs with a deficiency of lysosomal acid beta-galactosidase: a canine model of human GM1 gangliosidosis. J Vet Med Sci. 2003 Feb; 65(2):213-7. [PubMed: 12655116]