In this study, we conducted extensive analyses of brain data from subjects with PD, provided by the notable PPMI database, and showed that APOE ε2/ε4 and ε3/ε3 genotypes, total grey matter volume, and subcortical dopaminergic deficit in striatal structures (caudate and putamen) are significantly associated with PD. The gene discussed is APOE; the disease is Parkinson disease.