TGM2 and Parkinson disease: CSF levels of clusterin have been reported to be increased (Přikrylová Vranová et al., 2010; Vranová et al., 2014) or normal (van Dijk et al., 2013a), tissue transglutaminase (Vermes et al., 2004) increased in PD, and cystatin C normal in PD (Přikrylová Vranová et al., 2010; Yamamoto-Watanabe et al., 2010) and decreased in MSA (Yamamoto-Watanabe et al., 2010).