Affected gene: HEXB
Inheritance: Autosomal recessive
Mutation: CanFam3.1 (chr13) g.41680256_41680257del, c.444_445del
OMIA link: 001291-9615

Breeds appropriate for testing: Poodle

Symptoms:
Dogs affected by GM2-gangliosidosis Type II (Sandhoff disease or variant 0) exhibit progressive neurological deterioration due to the accumulation of GM2 gangliosides in the central nervous system. Symptoms typically appear between 6 months to 1 year of age and include muscle weakness, ataxia (loss of coordination), and progressive paralysis. Affected dogs may also experience vision loss and seizures as the disease progresses. The condition is fatal, and there is currently no effective treatment.

References:
  
Wenger, D. A., & Victoria, T. (2000). The GM2 gangliosidoses: beta-hexosaminidase deficiencies. The Neurology of Lysosomal Storage Disorders. Springer. DOI: 10.1007/978-1-4757-3166-5_12.
  
Martin, D. R., Krum, B. K., Varadarajan, G. S., Hathcock, T. L., Smith, B. F., & Martin, S. B. (2005). Sandhoff disease in a Golden Retriever: clinical, pathologic, and biochemical findings. Journal of Veterinary Diagnostic Investigation, 17(1), 73-77. DOI: 10.1177/104063870501700112.