Aging is the principal risk factor in various protein folding diseases, such as BAG3-, CRYαB- and DNAJB6-associated myofibrillar myopathies, as well as familial amyotrophic lateral sclerosis, Alzheimer's, Huntington's and Parkinson's diseases, all of which have been characterized as ‘gain-of-toxic-function’ diseases (Taylor et al., 2002). Here, BAG3 is linked to Parkinson disease.