Gangliosidosis type 2 (GM2) in Shiba-Inu

Gangliosidosis type 2 is an inherited lysosomal storage disease that causes accumulation of GM2 ganglioside-glycolipid in various body tissues. The GM2 gangliosidosis resulted from a deficiency of the hexosaminidase enzyme that splits GM2 ganglioside. The consequences are neuromuscular dysfunction and poor growth of puppies from an early age.

The clinical symptoms of GM2 are similar to those of GM1. The symptoms of the disease include small growth of affected puppies, ataxia, and head tremor. The first clinical signs occur at early age of the puppies; however, they are not distinct enough, but they become worse as the disease progresses. Later, there can be observed poor coordination of movements making walking almost impossible, general tremor, the dog is not able to eat, and its health condition leads to death or an indicated euthanasia.

GM2 in Shiba-Inu is caused by mutation c.618_620delCCT in exone 3 of HEXB gene. The inheritance of GM2 follows the autosomal recessive pattern. It means that the disease develops only in dogs that inherit the mutated gene from both parents. Individuals that carry only one copy of the mutated gene do not develop the disease, but they can transfer the mutated gene to their offspring. Therefore, it is important to test the breeding dogs to avoid spreading of the disease in the breed population.

.

Reference:

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., 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. : GM2 Gangliosidosis in Shiba Inu Dogs with an In-Frame Deletion in HEXB. J Vet Intern Med 31:1520-1526, 2017. Pubmed reference: 28833537.