NEFL and X-linked adrenoleukodystrophy: Applying the plasma NfL cut-off value of 8.33 pg/mL, we classified the presence or absence of CALD lesions for the respective patients (CALD-indicative demyelination: plasma NfL ≥8.33 pg/mL; asymptomatic X-ALD: plasma NfL <8.33 pg/mL, Fig. 4).