There were no significant associations found between peak peripherin or NfL levels and MRC-SS, mRS, ONLS or iRODS at symptom nadir, nor were peak levels associated with presence of cranial neuropathy or autonomic disturbances, degree of areflexia or sensory disturbance, or neurophysiological subtype when Bonferroni correction was applied. Here, PRPH is linked to cranial nerve neuropathy.