title: [Apolipoprotein E 4 gene is a risk factor for Alzheimer's disease].
abstract: OBJECTIVE
  To study the association of Alzheimer disease (AD) with apolipoprotein E (ApoE) epsilon 4 allele and to find the biological peripheral markers for the laboratory diagnosis of AD.
  
  
  METHODS
  107 patients with AD, 68 patients with vascular dementia (VD) and 74 sex- and age-matched non-demented healthy individuals (NDC) were collected. DNA from patients and healthy individuals was extracted from peripheral blood samples with the phenol-chloroform procedure and ApoE was investigated with the methods of polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP).
  
  
  RESULTS
  The frequency of epsilon 4 was significantly higher in AD than that in VD and NDC and there was no difference in the frequency of epsilon 4 between VD and NDC. The age at onset of the disease in the group carrying two epsilon 4 alleles was significantly younger than that in the group with one epsilon 4 allele in AD. Moreover, in comparison with AD patients without epsilon 4 allele, the age at onset in the group with one epsilon 4 allele was younger. Patients with epsilon 4 or without epsilon 4 allele in VD patients did not differ significantly in age at onset. Meanwhile, 3 familial AD cases were found, all carrying epsilon 4 allele.
  
  
  CONCLUSIONS
  AD and ApoE4 were closely related. ApoE epsilon 4 was a dangerous factor of AD and ApoE 4 allele made contribution to the heterogenicity of AD.
authors.affiliation: Department of Neurology, Beijing Hospital, Beijing 100730, China.
authors.forename: D
authors.initials: D
authors.lastname: Peng
authors.forename: X
authors.initials: X
authors.lastname: Xu
authors.forename: Y
authors.initials: Y
authors.lastname: Feng
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000483:Alleles; D000544:Alzheimer Disease / Q000235:genetics* / Q000473:pathology; D053327:Apolipoprotein E4; D001057:Apolipoproteins E / Q000235:genetics*; D004247:DNA / Q000235:genetics; D005260:Female; D005787:Gene Frequency; D006801:Humans; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D012307:Risk Factors
chemical_list: D053327:Apolipoprotein E4; D001057:Apolipoproteins E; D004247:DNA