Alzheimer disease (AD) co-pathology (intermediate or high ADNC), defined by a higher burden of tau neurofibrillary tangles (NFTs) and Aβ or neuritic plaques, is present in 28–89% of DLB individuals, with a higher prevalence compared to both Parkinson disease (PD) (around 10%) and PDD (35%) [29,30,31,32,47,48]. The gene discussed is MAPT; the disease is Parkinson disease.