Behavioral variant frontotemporal dementia with pathogenic variant in <i>MAPT</i> presenting as dementia with Lewy body disease

A 75-year-old Chinese American man presented to behavioral neurology clinic for a second opinion of dementia with Lewy body disease (DLB). The clinical manifestations met the criteria for a probable DLB diagnosis. Yet, in-depth evaluation unveiled clinical history, family history, and neuroimaging evidences that suggested a diagnosis of behavioral variant frontotemporal dementia (FTD). A heterozygous pathogenic variant in the microtubule-associated protein Tau (<i>MAPT</i>) was identified through genetic testing and confirmed the diagnosis of autosomal dominant <i>MAPT</i>-related FTD. This case is the first reported instance of <i>MAPT</i>-related FTD presenting with well-formed visual hallucinations in an elderly Chinese American.