When we looked into differentiating PD from MSA and PSP, NfL still exhibited very good discriminatory power with an AUC of 0.983 and 0.993, respectively (PD vs. MSA: a sensitivity and specificity of 100 and 95.6%, respectively; PD vs. PSP: a sensitivity and specificity of 82.5 and 100%, respectively). The gene discussed is NEFL; the disease is Parkinson disease.