Genetic studies of quantitative MCI and AD phenotypes in ADNI: Progress, opportunities, and plans

Alzheimers Dement. 2015 Jul;11(7):792-814. doi: 10.1016/j.jalz.2015.05.009.

Abstract

Introduction: Genetic data from the Alzheimer's Disease Neuroimaging Initiative (ADNI) have been crucial in advancing the understanding of Alzheimer's disease (AD) pathophysiology. Here, we provide an update on sample collection, scientific progress and opportunities, conceptual issues, and future plans.

Methods: Lymphoblastoid cell lines and DNA and RNA samples from blood have been collected and banked, and data and biosamples have been widely disseminated. To date, APOE genotyping, genome-wide association study (GWAS), and whole exome and whole genome sequencing data have been obtained and disseminated.

Results: ADNI genetic data have been downloaded thousands of times, and >300 publications have resulted, including reports of large-scale GWAS by consortia to which ADNI contributed. Many of the first applications of quantitative endophenotype association studies used ADNI data, including some of the earliest GWAS and pathway-based studies of biospecimen and imaging biomarkers, as well as memory and other clinical/cognitive variables. Other contributions include some of the first whole exome and whole genome sequencing data sets and reports in healthy controls, mild cognitive impairment, and AD.

Discussion: Numerous genetic susceptibility and protective markers for AD and disease biomarkers have been identified and replicated using ADNI data and have heavily implicated immune, mitochondrial, cell cycle/fate, and other biological processes. Early sequencing studies suggest that rare and structural variants are likely to account for significant additional phenotypic variation. Longitudinal analyses of transcriptomic, proteomic, metabolomic, and epigenomic changes will also further elucidate dynamic processes underlying preclinical and prodromal stages of disease. Integration of this unique collection of multiomics data within a systems biology framework will help to separate truly informative markers of early disease mechanisms and potential novel therapeutic targets from the vast background of less relevant biological processes. Fortunately, a broad swath of the scientific community has accepted this grand challenge.

Keywords: Alzheimer's disease (AD); Bioethical issues; Biomarkers; Cerebrospinal fluid (CSF); Cognition; Copy number variation (CNV); DNA; Genome-wide association studies (GWAS); Magnetic resonance imaging (MRI); Memory; Mild cognitive impairment (MCI); Next generation sequencing (NGS); Positron emission tomography (PET); Precision medicine; RNA.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Review

MeSH terms

  • Alzheimer Disease / diagnosis*
  • Alzheimer Disease / genetics*
  • Apolipoproteins E / genetics
  • Biomarkers / metabolism*
  • Cognitive Dysfunction / genetics*
  • Databases, Bibliographic / statistics & numerical data
  • Disease Progression
  • Genetic Association Studies
  • Humans
  • Membrane Transport Proteins / genetics
  • Mitochondrial Precursor Protein Import Complex Proteins
  • Neuroimaging

Substances

  • Apolipoproteins E
  • Biomarkers
  • Membrane Transport Proteins
  • Mitochondrial Precursor Protein Import Complex Proteins
  • TOMM40 protein, human