Importantly, we show using thioflavin T binding assays and transmission electron microscopy (TEM) that the IDR of both fly Hsp110 and human Hsp105α and Apg-1 Hsp110 homologs prevents the fibrilization of Aβ1-42 and α-synuclein, the highly amyloidogenic peptides involved in Alzheimer’s and Parkinson’s disease pathology, respectively. Here, HSPH1 is linked to Parkinson disease.