APOE epsilon 2 and epsilon 4 influence the susceptibility for Alzheimer's disease but not other dementias

Apolipoprotein E (APOE) genotype was determined in a population of patients with dementia, including 735 patients with Alzheimer's disease (AD), 75 with Frontotemporal Lobar Degeneration (FTLD), 97 with Vascular Dementia (VaD) and 40 with Lewy Body Dementia (LBD), as well as in 506 age-and gender-matched controls (CON). APOE. 2 allele frequency was lower in patients with AD (2.8%) than in CON (6.4%, P=0.001, OR: 0.41). Similar results were obtained comparing AD with FTLD (6.7%, P=0.01, OR: 0.37), at difference from VaD (5.6%, P>0.05) or LBD (5.0%, P>0.05). The frequency of the APOE. 4 allele was increased in patients with AD (25.1%) as compared with CON (8.2%, P=0.001, OR: 4.24), FTLD (11.3%, P=0.001, OR: 2.67), VaD (11.8%, P=0.001, OR: 3.02), or LBD (13.8%, P=0.048, OR: 2.07). The frequency of the. 4/. 4 genotype was increased in AD patients compared with controls (6.3 versus 0.8%, P=0.001, OR: 8.38). The presence of the. 2 allele is a protective factor for AD, whereas the. 4 allele acts as a risk factor for the disease. Both alleles do not influence the susceptibility to FTLD, LBD and VaD.