[Apolipoprotein E genotypes in patients investigated for dementia].

Certain genotypes of apolipoprotein E (apoE, locus APOE) are associated with an increased risk for development of Alzheimer's disease. We present the distribution of the APOE alleles (E2, E3 and E4) in 50 Danish patients referred to a dementia clinic. The distribution of alleles in patients with dementia was E2: 2, E3: 36 and E4: 38; and in 12 patients without dementia E2: 1, E3: 18, and E4: 5. The frequency of E4 alleles was significantly increased (chi 2 = 42; df = 1; p < 10(-4)) among patients with Alzheimer's disease compared with a Danish control population. The study demonstrates a strong association between Alzheimer's disease and the E4 allele. No difference was found in the frequency of the E4 allele between Alzheimer and non-Alzheimer demented patients.