Finally, we provide the first evidence linking naturally occurring genetic variation in a lysosomal GAG catabolism gene (ARSB) to differences in CWD susceptibility in farmed US WTD, but also further confirm the involvement of genes underlying other neurodegenerative diseases such as Parkinson’s, Alzheimer’s, and various prion diseases of mammals, including scrapie and sporadic Creutzfeldt–Jakob disease. The gene discussed is ARSB; the disease is Parkinson disease.