title: Genetic heterogeneity in Alzheimer disease and implications for treatment strategies.
abstract: Since the original publication describing the illness in 1907, the genetic understanding of Alzheimer's disease (AD) has advanced such that it is now clear that it is a genetically heterogeneous condition, the subtypes of which may not uniformly respond to a given intervention. It is therefore critical to characterize the clinical and preclinical stages of AD subtypes, including the rare autosomal dominant forms caused by known mutations in the PSEN1, APP, and PSEN2 genes that are being studied in the Dominantly Inherited Alzheimer Network study and its associated secondary prevention trial. Similar efforts are occurring in an extended Colombian family with a PSEN1 mutation, in APOE ε4 homozygotes, and in Down syndrome. Despite commonalities in the mechanisms producing the AD phenotype, there are also differences that reflect specific genetic origins. Treatment modalities should be chosen and trials designed with these differences in mind. Ideally, the varying pathological cascades involved in the different subtypes of AD should be defined so that both areas of overlap and of distinct differences can be taken into account. At the very least, clinical trials should determine the influence of known genetic factors in post hoc analyses.
authors.affiliation: Mary S. Easton Center for Alzheimer's Disease Research, David Geffen School of Medicine at University of California, Los Angeles, 10911 Weyburn Ave., #200, Los Angeles, 90095-7226, CA, USA, jringman@mednet.ucla.edu.
authors.forename: John M
authors.initials: JM
authors.lastname: Ringman
authors.forename: Alison
authors.initials: A
authors.lastname: Goate
authors.forename: Colin L
authors.initials: CL
authors.lastname: Masters
authors.forename: Nigel J
authors.initials: NJ
authors.lastname: Cairns
authors.forename: Adrian
authors.initials: A
authors.lastname: Danek
authors.forename: Neill
authors.initials: N
authors.lastname: Graff-Radford
authors.forename: Bernardino
authors.initials: B
authors.lastname: Ghetti
authors.forename: John C
authors.initials: JC
authors.lastname: Morris
mesh_terms: D000544:Alzheimer Disease / Q000235:genetics* / Q000503:physiopathology / Q000628:therapy*; D016564:Amyloid beta-Protein Precursor / Q000235:genetics; D000818:Animals; D018740:Genetic Heterogeneity; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics*; D053764:Presenilin-1 / Q000235:genetics; D053766:Presenilin-2 / Q000235:genetics
chemical_list: D016564:Amyloid beta-Protein Precursor; D008565:Membrane Proteins; C508853:PSEN1 protein, human; C508861:PSEN2 protein, human; D053764:Presenilin-1; D053766:Presenilin-2