Prediction of Alzheimer's disease using the CSF Abeta42/Abeta40 ratio in patients with mild cognitive impairment

Dement Geriatr Cogn Disord. 2007;23(5):316-20. doi: 10.1159/000100926. Epub 2007 Mar 19.


Evidence supports an important role for beta-amyloid (Abeta) in the pathogenesis of Alzheimer's disease (AD). Here, we investigate baseline levels of the 40- and 42-amino-acid-long Abeta peptides (Abeta40 and Abeta42) in cerebrospinal fluid (CSF) from a cohort of patients with mild cognitive impairment (MCI, n = 137) in relation to the final diagnosis after 4-6 years of follow-up time. CSF Abeta42 concentration at baseline and the Abeta42/Abeta40 ratio were significantly decreased in the MCI patients who developed AD as compared to cognitively stable MCI patients and MCI patients who developed other forms of dementia (p < 0.001). The baseline levels of Abeta40 were similar in all MCI groups but correlated with change in Mini Mental State Examination scores in converters to AD. The Abeta42/Abeta40 ratio was superior to Abeta42 concentration with regard to identifying incipient AD in MCI (p < 0.05). In conclusion, the data provide further support for the view that amyloid precursor protein metabolism is disturbed in early sporadic AD and points to the usefulness of the Abeta42/Abeta40 ratio as a predictive biomarker for AD.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Alzheimer Disease / cerebrospinal fluid*
  • Alzheimer Disease / diagnosis
  • Amyloid beta-Peptides / cerebrospinal fluid*
  • Amyloid beta-Protein Precursor / metabolism
  • Analysis of Variance
  • Biomarkers / cerebrospinal fluid
  • Case-Control Studies
  • Cognition Disorders / cerebrospinal fluid*
  • Cohort Studies
  • Female
  • Humans
  • Longitudinal Studies
  • Male
  • Middle Aged
  • Peptide Fragments / cerebrospinal fluid*
  • Predictive Value of Tests
  • Reference Values
  • Risk Factors
  • Severity of Illness Index
  • Statistics, Nonparametric


  • Amyloid beta-Peptides
  • Amyloid beta-Protein Precursor
  • Biomarkers
  • Peptide Fragments
  • amyloid beta-protein (1-40)
  • amyloid beta-protein (1-42)