HTT and neurodegenerative disease: Many neurodegenerative diseases involve protein misfolding and/or aggregation, such as Aβ and tau in AD, α-synuclein in Parkinson’s disease, Huntingtin in Huntington’ disease, and superoxide dismutase in Amyotrophic lateral sclerosis.3,54 The primary risk factor for developing neurodegenerative diseases is aging with accumulation of oxidative stress and proteotoxicity.