Comparison between Early-Onset and Late-Onset Alzheimer's Disease Patients with Amnestic Presentation: CSF and (18)F-FDG PET Study.

Background/aims: To investigate the differences in brain glucose consumption between patients with early onset of Alzheimer's disease (EOAD, aged ≤65 years) and patients with late onset of Alzheimer's disease (LOAD, aged >65 years).

Methods: Differences in brain glucose consumption between the groups have been evaluated by means of Statistical Parametric Mapping version 8, with the use of age, sex, Mini-Mental State Examination and cerebrospinal fluid values of AΒ1-42, phosphorylated Tau and total Tau as covariates in the comparison between EOAD and LOAD.

Results: As compared to LOAD, EOAD patients showed a significant decrease in glucose consumption in a wide portion of the left parietal lobe (BA7, BA31 and BA40).

Inverse effect of the APOE epsilon4 allele in late- and early-onset Alzheimer's disease.

In Alzheimer's disease patients (AD), the age at onset (AAO) ranges from 40 to 90. Usually, AD patients who develop symptoms before the age of 65 are classified as early onset (EO). The best known genetic risk factor for AD is the ε4 allele of the apolipoprotein E (APOE).