We also explored the relationship between the set of 15 selected AI features and clinical and biomarker measures of PD disease severity namely MDS-UPDRS total and part III scores (where higher values indicate more severe disease), CSF total α-synuclein, and dopamine transporter binding in striatum measured with SPECT (DAT-SBR; where lower values indicate lower (worse) DAT binding). The gene discussed is SLC6A3; the disease is Parkinson disease.