Correlations of contactin-1 and -2 with commonly used CSF markers (t-α-syn, tTau and pTau) and clinical measures of disease severity such as MMSE score, disease duration, Hoehn and Yahr (H&Y) scale (only in the PD group) and Unified Parkinson’s Disease Rating Scale (UPDRS-III) (only in the PD group) were calculated within each diagnostic group. The gene discussed is CNTN1; the disease is Parkinson disease.