[Frontotemporal dementia in association with a family history of dementia and ApoE polymorphism].

OBJECTIVE: To examine the association between apolipoprotein E (ApoE) and a family history of dementia in 1st- and 2nd-degree relatives of patients with frontotemporal dementia (FTD) with a dementia onset by age 70.
METHODS: The study included 494 dementia patients (73 FTD patients) and 82 cognitively normal spousal control subjects. Neuropsychiatric examination, Consortium To Establish a Registry on Alzheimer's Disease (CERAD) testing, the clock-drawing test, and ApoE genotyping were performed in patients and controls. All patients were examined by magnetic resonance imaging. FTD patients fulfilled the Lund-Manchester criteria.
RESULTS: All controls had normal Mini Mental State exam (MMSE > or =27). 28 of the 82 spousal controls were excluded because CERAD test results were consistent with the diagnosis of mild cognitive impairment (MCI) or the CERAD was incomplete. The remaining 54 spousal controls had CERAD test results with z-scores >/= -1.5. The number of dementia patients with FTD was 73. Apo epsilon4 homozygosity was found in 13.6% of the FTD patients. None of the spousal controls was homozygous for the Apo epsilon4 genotype (p=0.005). A positive family history of dementia was lowest among cognitively normal spousal controls (9.3%). It rose to 35.6% for FTD patients and was highest among Apo epsilon4 homozygous FTD patients (50.0%).
CONCLUSIONS: Apo epsilon4 homozygosity is associated with a family history of dementia and FTD in our cohort if the current clinical criteria are employed. It is likely that autopsy might reveal amyloid beta deposits typical for Alzheimer's disease among the Apo epsilon4 homozygous patients with frontotemporal clinical presentation and neuroimaging consistent with FTD. Apo epsilon4 homozygosity has not yet been defined as an exclusion criterion for the diagnosis of FTD. In the future, a revision of the clinical criteria should consider the ApoE genotype.