Gangliosidosis type 1 (GM1) in Shiba-Inu

Gangliosidosis of type 1 (GM1) is an inherited lysosomal storage disorder that causes accumulation of the ganglioside-glycolipid in various body tissues, especially in the brain and the nervous system and in other internal organs. The gangliosides are accumulated due to the absence of the enzyme beta-galactosidase that is responsible for splitting gangliosides – and results in the cellular catabolism disorder. The disease is characterized by progressive neuromuscular dysfunction and disturbed growth from an early age. The GM1 occurs in cats, dogs, sheep, cattle and in humans.

The clinical symptoms of GM1 include small growth of puppies, ataxia, motor disorders (dysmetria) and head tremors. The first clinical signs of the disease (weight loss and „wide-based“ gate) occur at the age of six to eight weeks, although they can be much less distinct. The clear signs such as progressive loss of balance and tremor can be observed at the age of 7 months. The reactions of the affected dogs to various sounds and touches may be unusual.  With the progress of the symptoms the affected dogs are not able to eat and to drink and later, the dog is unable to stand on its feet. The worsening of the health condition results in the death of the dog or in an indicated euthanasia.

GM1 in Shiba-Inu is caused by the deletion of cytosine in exon 15 of GLB1-gene. The inheritance of GM1 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.

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Reference:

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 Journal of Inherited Metabolic Disease 25:525-526, 2002.