TPPP and Parkinson disease: In addition, the levels of SYN are believed to be different in the cerebrospinal fluids of patients with PD or MSA (Andersen et al., 2017; Maass et al., 2019; Cong et al., 2020), while TPPP/p25 has been detected in cerebrospinal fluid (Vincze et al., 2011).