The phenotypic spectrum of variants in GRN and MAPT often includes atypical parkinsonism that might even predominate over the clinical presentation.1 Interestingly, both GRN and MAPT represent PD susceptibility/risk loci discovered through association studies, and their protein products are functionally related to PD proteins.29,30 Thus, at least GRN and MAPT should be tested routinely in PD patients. The gene discussed is MAPT; the disease is Parkinson disease.