title: Association of apolipoprotein E polymorphism in late-onset Alzheimer's disease and vascular dementia in Brazilians.
abstract: The genetic basis for dementias is complex. A common polymorphism in the apolipoprotein E (APOE) gene is considered to be the major risk factor in families with sporadic and late-onset Alzheimer's disease as well as in the general population. The distribution of alleles and genotypes of the APOE gene in late-onset Alzheimer's disease (N = 68), other late-life dementias (N = 39), and in cognitively normal controls (N = 58) was determined, as also was the risk for Alzheimer's disease associated with the epsilon4 allele. Peripheral blood samples were obtained from a total of 165 individuals living in Brazil aged 65-82 years. Genomic DNA was amplified by the polymerase chain reaction and the products were digested with HhaI restriction enzyme. APOE epsilon2 frequency was considerably lower in the Alzheimer's disease group (1%), and the epsilon3 allele and epsilon3/epsilon3 genotype frequencies were higher in the controls (84 and 72%, respectively) as were the epsilon4 allele and epsilon3/epsilon4 genotype frequencies in Alzheimer's disease (25 and 41%, respectively). The higher frequency of the epsilon4 allele in Alzheimer's disease confirmed its role as a risk factor, while epsilon2 provided a weak protection against development of the disease. However, in view of the unexpectedly low frequency of the epsilon4 allele, additional analyses in a more varied Brazilian sample are needed to clarify the real contribution of apolipoprotein E to the development of Alzheimer's disease in this population.
authors.affiliation: Departamento de Biologia Molecular, Faculdade de Medicina de São José do Rio Preto, SP, Brasil.
authors.forename: D R S
authors.initials: DR
authors.lastname: Souza
authors.forename: M R
authors.initials: MR
authors.lastname: de Godoy
authors.forename: J
authors.initials: J
authors.lastname: Hotta
authors.forename: E H
authors.initials: EH
authors.lastname: Tajara
authors.forename: A C
authors.initials: AC
authors.lastname: Brandão
authors.forename: S
authors.initials: S
authors.lastname: Pinheiro Júnior
authors.forename: W A
authors.initials: WA
authors.lastname: Tognola
authors.forename: J E
authors.initials: JE
authors.lastname: dos Santos
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000483:Alleles; D000544:Alzheimer Disease / Q000235:genetics*; D001057:Apolipoproteins E / Q000235:genetics*; D016022:Case-Control Studies; D015140:Dementia, Vascular / Q000235:genetics*; D005260:Female; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D008297:Male; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D012307:Risk Factors
chemical_list: D001057:Apolipoproteins E