title: Apolipoprotein E epsilon4 allele frequency and age at onset of Alzheimer's disease.
abstract: The age distribution of the epsilon4 allelic form of the apolipoprotein E gene (APOE) was investigated in 630 patients with Alzheimer's disease (AD) with onset age ranging from 35 to 90 years. Overall, mean age at onset in APOE epsilon4 allele bearers was significantly later than that in nonbearers. However, when stratified into early onset AD (EOAD) and late onset (LOAD) groups, mean age at onset in EOAD cases bearing APOE epsilon4 allele was later than that in those EOAD cases without epsilon4 allele, whereas in LOAD mean age at onset in cases bearing APOE epsilon4 allele was earlier than in those without epsilon4 allele. When analysed by decade, it was observed that 37% of the total number of APOE epsilon4 allele bearers, and 43% of total number of cases with APOE epsilon4/epsilon4 genotype fell into the 60-69 years age class. Hence, APOE epsilon4 allele frequency, at 0.44, was highest in the 60-69 years age class, progressively decreasing either side of this age group. APOE epsilon4 allele therefore has its maximum impact between onset ages of between 60 and 70 years.
authors.affiliation: Clinical Neuroscience Research Group, Division of Medicine and Neuroscience, University of Manchester, Greater Manchester Neurosciences Centre, Hope Hospital, Salford, UK.
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Davidson
authors.forename: Linda
authors.initials: L
authors.lastname: Gibbons
authors.forename: Antonia
authors.initials: A
authors.lastname: Pritchard
authors.forename: Jayne
authors.initials: J
authors.lastname: Hardicre
authors.forename: Joanne
authors.initials: J
authors.lastname: Wren
authors.forename: Cheryl
authors.initials: C
authors.lastname: Stopford
authors.forename: Camille
authors.initials: C
authors.lastname: Julien
authors.forename: Jennifer
authors.initials: J
authors.lastname: Thompson
authors.forename: Antony
authors.initials: A
authors.lastname: Payton
authors.forename: Stuart M
authors.initials: SM
authors.lastname: Pickering-Brown
authors.forename: Neil
authors.initials: N
authors.lastname: Pendleton
authors.forename: Michael A
authors.initials: MA
authors.lastname: Horan
authors.forename: Alistair
authors.initials: A
authors.lastname: Burns
authors.forename: Nitin
authors.initials: N
authors.lastname: Purandare
authors.forename: Corinne L
authors.initials: CL
authors.lastname: Lendon
authors.forename: David
authors.initials: D
authors.lastname: Neary
authors.forename: Julie S
authors.initials: JS
authors.lastname: Snowden
authors.forename: David M A
authors.initials: DM
authors.lastname: Mann
mesh_terms: D017668:Age of Onset; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000453:epidemiology* / Q000235:genetics*; D053327:Apolipoprotein E4 / Q000235:genetics*; D003072:Cognition Disorders / Q000175:diagnosis / Q000453:epidemiology; D005260:Female; D005787:Gene Frequency / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D012720:Severity of Illness Index
chemical_list: D053327:Apolipoprotein E4