NEFL and prion disease: This might also explain the very high sensitivity of NfL for other slowly progressive prion disease subtypes showing low CSF values of t-tau and protein 14-3-3 [e.g., sCJD MM2C, gCJD E200K, GSS, FFI, and variable protease-sensitive prionopathy (VPSPr)] (Abu-Rumeileh et al., 2018b, 2019a; Zerr et al., 2018).