title: Is early-onset Alzheimer disease a distinct subgroup within the Alzheimer disease population?
abstract: Although patients with Alzheimer disease (AD) share major clinical and neurohistologic features regardless of age of onset, the hypothesis that early-onset AD comprises a distinct subgroup remains viable. Most studies addressing this hypothesis find quantitative differences between early- and late-onset AD patients. Early-onset AD is characterized by shorter survival, more rapid cognitive deterioration, greater frequency of language disturbance, more severe and widespread neurochemical abnormalities, and a greater density of neurohistologic lesions. In addition, both the chromosome 14 genetic abnormality and chromosome 21 amyloid precursor protein mutations appear restricted to early-onset familial AD. Age of onset of AD subjects may be relevant to the design of clinical trials. For example, the efficacy of a drug that slows disease progression may be more easily demonstrated in subjects with early-onset disease.
authors.affiliation: University of Washington School of Medicine, Department of Psychiatry and Behavioral Sciences, Seattle, USA.
authors.forename: M A
authors.initials: MA
authors.lastname: Raskind
authors.forename: A
authors.initials: A
authors.lastname: Carta
authors.forename: D
authors.initials: D
authors.lastname: Bravi
mesh_terms: D017668:Age of Onset; D000544:Alzheimer Disease / Q000145:classification* / Q000175:diagnosis*; D002883:Chromosomes, Human, Pair 14 / Q000378:metabolism; D002891:Chromosomes, Human, Pair 21 / Q000378:metabolism; D003071:Cognition; D006801:Humans; D009483:Neuropsychological Tests; D013997:Time Factors