Amyloid PET studies have shown asymmetric amyloid deposition in preclinical Alzheimer’s disease, which becomes more symmetric with cognitive decline,46 while asymmetric tau patterns have also been described in tau PET studies as well including a left-sided predominant subtype in 19% of patients with Alzheimer’s disease.47 This evidence concerns the gene MAPT and early-onset autosomal dominant Alzheimer disease.