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Gangliosidosis type 2 (GM2) - Shiba Inu type
| Acronym: | GM2 |
| Gene: | HEXB |
| Mutation: | c.849_851del |
| Inheritance: | Autosomal Recessive |
| Sample type: | CHS (Cheek Swab), WBE (Whole Blood EDTA) |
Genetics and characteristics
GM2-gangliosidosis is a genetic lysosomal disease that belongs to a group of lysosomal disorders known as gangliosidosis, caused by the accumulation of lipids gangliosides. Gangliosidosis is a common lethal disease in some dog breeds including Shiba-Inu dogs. The first symptoms occur around 9 to 12 months of age causing progressive neurological degradation and asymmetric growth often leading to death or euthanasia by the age of 18 to 23 months. Neurological symptoms include stiff gait, loss of balance, falling ataxia, decreased menace response, vision defect or loss and decreased level of consciousness. GM2 gangliosidoses is a result of a deletion in a gene encoding beta-hexosaminidase (Hex), an enzyme that catalyzes the biodegradation of lipids gangliosides. In case of unfunctioning beta-hexosaminidase enzyme, gangliosides start to accumulate, especially in the lysosomes of neurons, causing problems.
Gangliosidosis type 2 (GM2) in Shiba-Inu dogs is inherited as an autosomal recessive trait meaning two copies of the mutated gene are required for the disease to develop. Dogs with only one copy of the mutated gene will not develop the disease but may act as carriers and pass the mutation to their offspring. Early detection by genetic testing can identify carriers and prevent the future development of this lethal disease in puppies.
Results Reported As
Test Result |
Interpretation of test result |
CLEAR |
Tested mutation was not detected in animal with „clear“ result. Animal tested as clear has wild-type allele in homozygous state (i.e. two pairs of healthy alleles). It will not develop disease caused by tested mutation.* It will pass only wild-type allele to its offspring. |
CARRIER |
Tested mutation was detected in animal with „carrier“ result. Animal tested as carrier has one wild-type and one mutation allele, it is in heterozygous state. It will not develop disease caused by tested mutation.* It can pass wild-type or mutation allele to its offspring. |
AFFECTED |
Tested mutation was detected in animal with „affected“ result. Animal tested as affected has two copies of mutation alleles affecting the gene. It is likely the animal will experience a genetic disorder due to this mutation.** It will pass only mutation allele to its offspring. |
*Test excludes only tested mutation but not possible unknown mutations or factors that can lead to similar condition/symptoms.
** Potential unknown mutations or multiple other factors can possibly affect the likelihood of experiencing a genetic disorder.
References:
Kolicheski, A., Johnson, G. S., Villani, N. A., O Brien, D. P., Mhlanga-Mutangadura, T., Wenger, D. A., Mikoloski, K., Eagleson, J. S., Taylor, J. F., Schnabel, R. D., & Katz, M. L. (2017). GM2 Gangliosidosis in Shiba Inu Dogs with an In-Frame Deletion in HEXB. Journal of veterinary internal medicine, 31(5), 1520–1526. https://doi.org/10.1111/jvim.14794
Wang, P., Henthorn, P.S., Galban, E., Lin, G., Takedai, T., Casal, M. Canine GM2-gangliosidosis Sandhoff disease associated with a 3-base pair deletion in the HEXB gene. J Vet Intern Med 32:340-347, 2018. Pubmed reference: 29106755. DOI: 10.1111/jvim.14862.