The apolipoprotein E epsilon4 allele is not a significant risk factor for frontotemporal dementia.

Frontotemporal dementia (FTD) is the most common early-onset non-Alzheimer's dementia (non-AD). Although the role of the epsilon4 allele of apolipoprotein E (ApoE) has been well established in AD, studies of ApoE allele distribution in patients with FTD have produced variable results. We studied 33 rigorously diagnosed FTD patients, including several who were pathologically confirmed, and compared the frequency of the epsilon4 allele in patients with FTD with the frequency in those with early-onset AD (EOAD), in those with late-onset AD (LOAD), and in non-demented elderly controls. The frequency of ApoE epsilon4 was 21% in patients with FTD, significantly less than the ApoE epsilon4 frequency in those patients with EOAD (38%) and those with LOAD (40%), but not significantly different from the ApoE epsilon4 frequency in elderly controls (13%).