title: Apolipoprotein E epsilon 2 allele promotes longevity and protects patients with Down's syndrome from dementia.
abstract: Although individuals with Down's syndrome nearly always develop the clinical and pathological features of Alzheimer's disease, some clearly do not become demented despite living into their sixth and seventh decades. Genetic variation at the apolipoprotein E locus has recently been shown to be an important determinant of Alzheimer's disease, with the epsilon 4 allele having been shown to be associated with the disease and, at least in some cases, the epsilon 2 allele being negatively associated with the disease. Here we show, in a series of clinically assessed individuals with Down's syndrome, that the epsilon 2 allele of ApoE is associated with both longevity and the absence of clinical evidence of dementia. These data show that the clinical phenotype of Down's syndrome can be modulated by genes on chromosomes other than chromosome 21. The importance of this observation to the pathogenesis of Alzheimer's disease, both in Down's syndrome and in general, is discussed.
authors.affiliation: Department of Psychiatry, Charing Cross and Westminster Medical School, London, UK.
authors.forename: M C
authors.initials: MC
authors.lastname: Royston
authors.forename: D
authors.initials: D
authors.lastname: Mann
authors.forename: S
authors.initials: S
authors.lastname: Pickering-Brown
authors.forename: F
authors.initials: F
authors.lastname: Owen
authors.forename: R
authors.initials: R
authors.lastname: Perry
authors.forename: R
authors.initials: R
authors.lastname: Raghavan
authors.forename: C
authors.initials: C
authors.lastname: Khin-Nu
authors.forename: S
authors.initials: S
authors.lastname: Tyrer
authors.forename: K
authors.initials: K
authors.lastname: Day
authors.forename: R
authors.initials: R
authors.lastname: Crook
mesh_terms: D017668:Age of Onset; D000368:Aged; D000483:Alleles; D001057:Apolipoproteins E / Q000235:genetics*; D003704:Dementia / Q000209:etiology*; D004314:Down Syndrome / Q000150:complications* / Q000235:genetics*; D006579:Heterozygote; D006801:Humans; D008136:Longevity / Q000502:physiology*; D008875:Middle Aged
chemical_list: D001057:Apolipoproteins E