Additional genes associated with Parkinsonism identified from relatives or patient cohorts include ATP13A2, C9ORF72, FBXO7, PLA2G6, POLG1, SCA2, SCA3, SYNJ1, and RAB39B. Parkinsonism due to mutations in these genes is quite rare and usually associated with features atypical for PD (e.g., prominent cognitive impairment, ophthalmological abnormalities, pyramidal signs, or ataxia; Kalia and Lang, 2015). This evidence concerns the gene POLG and Parkinsonism.