Apolipoprotein E genotype in senile dementia and Downʹs syndrome

Apolipoprotein E genotypes were determined in 30 healthy elderly controls, 42 patients with Alzheimerʹs disease, 13 subjects with vascular dementia and 31 individuals with Downʹs syndrome. The frequency of ε4 allele carriers was significantly increased in the Alzheimerʹs disease group (χ2=4.918, P<0.05) but also in the vascular dementia subjects (P<0.01, Fisherʹs exact test). The established relationship between genotype and age at onset of Alzheimerʹs disease was not statistically significant in these data. Frequencies of the genotypes in the Downʹs syndrome group did not differ from those of controls. The results obtained in this sample of the Italian population suggest that the apolipoprotein E genotype may be of limited use in the differential diagnosis of dementia.