title: [Association between the A2 allele of the HLA system and age at onset of Alzheimer's disease].
abstract: OBJECTIVE
  Alzheimer is a multifactor disease occurring in a sensitive genetic territory. The e4 allele of the apolipoprotein E (APO E) is a recognised factor of risk. Some studies have suggested an association between the A2 allele of the HLA system and an earlier onset of the disease notably when it appears before the age of 64 or after the age of 75. The aim of our study was to explore this hypothesis in an independent sample of patients.
  
  
  METHODS
  We compared the influence of the A2 allele of the HLA system on the age at onset of the disease in two groups of Caucasian patients presenting with Alzheimer's disease: early onset if the disease appeared before the age of 60 (n= 31) and late onset if it had appeared after the age of 75 (n= 44). The influence of the e4 allele of APO E was also taken into account.
  
  
  RESULTS
  The comparison of the patients depending on the presence or not of at least one HLA-A2 allele revealed no significant difference, whatever the group of patients studied, in the age at onset of the disease.
  
  
  CONCLUSIONS
  The age at onset of Alzheimer's disease was not influenced in our study by the presence of the HLA-A2 allele.
authors.affiliation: Service de médecine interne et de gérontologie clinique, CHU Purpan-Casselardit, Toulouse.Fatinour@aol.com
authors.forename: F
authors.initials: F
authors.lastname: Nourhashémi
authors.forename: S
authors.initials: S
authors.lastname: Gillette-Guyonnet
authors.forename: M
authors.initials: M
authors.lastname: Fort
authors.forename: S
authors.initials: S
authors.lastname: Andrieu
authors.forename: M
authors.initials: M
authors.lastname: Abbal
authors.forename: J-L
authors.initials: JL
authors.lastname: Albarède
authors.forename: B
authors.initials: B
authors.lastname: Vellas
mesh_terms: D000367:Age Factors; D000368:Aged; D000483:Alleles; D000544:Alzheimer Disease / Q000453:epidemiology / Q000235:genetics*; D001057:Apolipoproteins E / Q000235:genetics; D016009:Chi-Square Distribution; D005260:Female; D015789:HLA-A2 Antigen / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D012737:Sex Factors; D018709:Statistics, Nonparametric
chemical_list: D001057:Apolipoproteins E; D015789:HLA-A2 Antigen