CST3 and Alzheimer disease: Genetically, the CST3 B haplotype of cystatin C was considered to be a risk factor for AD, frontotemporal dementia (FTD), and Lewy body dementia (LBD) (Finckh et al., 2000; Bertram et al., 2007; Maetzler et al., 2010; Hua et al., 2012).