HTT and neurodegenerative disease: The cysteine proteases cathepsin B (CTSB) and cathepsin L (CTSL) are involved in the clearance of various neurodegenerative disease-related proteins such as amyloid-\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$\:{\upbeta\:}$$\end{document}, huntingtin and the prion protein.