Apolipoprotein E polymorphism in elderly Chilean people with Alzheimer's disease

As a part of the WHO Age-Associated Dementia Project, Chile has been partic ipating in a cross-national survey on dementia frequency and determinants s ince 1989. In the present study, apolipoprotein E (ApoE) polymorphism genot ypes have been compared in 95 patients with Alzheimer's disease (AD) (mean age 80.7; 95% CI 79.2-82.2, range 66-97) and 187 healthy people (mean age 7 8.2; 95% CI 77.2-79.2, range 65-93). Isoelectric focusing and immunoblottin g with anti-human ApoE polyclonal antibody were used to determine the distr ibution of ApoE genotypes. Dementia was diagnosed according to DSM-III-R an d ICD-10 clinical criteria. The diagnosis of probable or possible AD was ma de according to the NINCDS-ADRDA criteria. The ApoE allele frequencies in h ealthy people were calculated to be epsilon 2 = 0.07, epsilon 3 = 0.74 and epsilon 4 = 0.19. In the probable AD disease group, the frequencies were ep silon 2 = 0.08, epsilon 3 = 0.52 and epsilon 4 = 0.40. The odds ratio (OR) for epsilon 4 carriers compared with non-epsilon 4 carriers was estimated t o be 2.9 (95% CI 1.7-5.1). Taking the genotype epsilon 3/epsilon 3 as the r eference group, the OR for the epsilon 4/epsilon 4 genotype was estimated t o be 12.8 (95% CI 3.9-47.6) and for epsilon 3/epsilon 4 subjects it was 2.4 (1.3-4.5). These results support the association between ApoE epsilon 4 al lele with late-onset AD in a Chilean population.