Thereby, ALS is characterized by aggregates of RNA-binding proteins such as TAR DNA binding protein 43 (TDP-43), while PD is associated with α-synuclein-containing aggregates and fibrils, AD with β-amyloid (Aβ) plaques and HD with aggregation-prone huntingtin (Htt) with extended polyglutamine stretches (Jellinger 2009). Here, HTT is linked to Parkinson disease.