CTSD and Huntington disease: Given the previously described autophagic dysfunction in HD, and their role in other neurodegenerative diseases, we pre-specified 5 lysosomal proteins as primary analytes to study: LAMP1, LAMP2, GM2A, Cathepsin D and F. The remaining 13 proteins, pertaining to other aspects of the endo-lysosomal and ubiquitin-proteasome system, were assessed in a separate exploratory analysis.