In line with this hypothesis, a reduction of CSF/plasma cystatin C was described in AD, FTD as well as in LBD patients and it was associated with an anticipation of dementia onset (Rüetschi et al., 2005; Sundelöf et al., 2008; Hansson et al., 2009; Ghidoni et al., 2010; Maetzler et al., 2010; Zhong et al., 2013). Here, CST3 is linked to frontotemporal dementia.