title: CSF soluble amyloid precursor proteins in the diagnosis of incipient Alzheimer disease.
abstract: OBJECTIVE
  To explore if soluble amyloid precursor proteins (sAPP) in CSF improve the identification of patients with incipient Alzheimer disease (AD) in a group of patients with mild cognitive impairment (MCI).
  
  
  METHODS
  A cohort study with follow-up assessments of 58 patients with MCI with baseline CSF sampling was conducted: 21 patients had progressed to probable AD (MCI-AD), 27 still had MCI, 8 had reverted to normal (MCI-NAD), and 2 patients with frontotemporal dementia (FTD) were excluded. Sixteen additional patients with FTD were included to explore the specificity of the CSF markers. CSF concentrations of sAPPα, sAPPβ, tau, and Aβ(1-42) were measured with sensitive and specific ELISAs. Associations between diagnostic status, CSF protein concentrations, and other patient characteristics were explored using multiple logistic regression analyses with stepwise variable selection. The optimal sensitivity and specificity of the best models were derived from receiver operating characteristic curves.
  
  
  RESULTS
  The MCI-AD group had significantly higher sAPPβ concentrations than the MCI-NAD and the FTD groups. A combination of sAPPβ, tau, and age differentiated the MCI-AD and the MCI-NAD groups with a sensitivity of 80.00% and a specificity of 81.00%. The best model for the differentiation of the MCI-AD and the FTD groups included sAPPβ and tau, and showed a sensitivity of 95.20% and a specificity of 81.20%. Aβ(1-42) and sAPPα did not significantly contribute to the models.
  
  
  CONCLUSIONS
  These findings suggest that sAPPβ may be clinically useful, and superior to Aβ(1-42), in the early and differential diagnosis of incipient AD.
authors.affiliation: Department of Psychiatry and Psychotherapy, Technische Universität München, Klinikum rechts der Isar, 81675 München, Germany. robert.perneczky@lrz.tum.de
authors.forename: R
authors.initials: R
authors.lastname: Perneczky
authors.forename: A
authors.initials: A
authors.lastname: Tsolakidou
authors.forename: A
authors.initials: A
authors.lastname: Arnold
authors.forename: J
authors.initials: J
authors.lastname: Diehl-Schmid
authors.forename: T
authors.initials: T
authors.lastname: Grimmer
authors.forename: H
authors.initials: H
authors.lastname: Förstl
authors.forename: A
authors.initials: A
authors.lastname: Kurz
authors.forename: P
authors.initials: P
authors.lastname: Alexopoulos
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000134:cerebrospinal fluid* / Q000150:complications / Q000175:diagnosis* / Q000235:genetics; D016229:Amyloid beta-Peptides / Q000134:cerebrospinal fluid; D016564:Amyloid beta-Protein Precursor / Q000134:cerebrospinal fluid*; D001057:Apolipoproteins E / Q000235:genetics; D003072:Cognition Disorders / Q000134:cerebrospinal fluid / Q000209:etiology / Q000235:genetics; D015331:Cohort Studies; D018450:Disease Progression; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D057180:Frontotemporal Dementia / Q000134:cerebrospinal fluid; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D010446:Peptide Fragments / Q000134:cerebrospinal fluid; D011569:Psychiatric Status Rating Scales; D016875:tau Proteins / Q000134:cerebrospinal fluid
chemical_list: D016229:Amyloid beta-Peptides; D016564:Amyloid beta-Protein Precursor; D001057:Apolipoproteins E; C054369:MAPT protein, human; D010446:Peptide Fragments; C075222:amyloid beta-protein (1-42); D016875:tau Proteins