The genome-wide association study
of the Alzheimer’s Disease Genetics Consortium

A collaborative effort

The Alzheimer's Disease Genetics Consortium (ADGC) Genome-wide Association Study (GWAS) was launched as a collaborative effort, leveraging the collective resources of the AD research community, to identify Alzheimer’s disease genes. ADGC, led by Gerard Schellenberger at the University of Pennsylvania, is a partnership involving:

  • the National Alzheimer’s Coordinating Center (NACC)
  • the National Cell Repository for Alzheimer’s Disease (NCRAD)
  • the Alzheimer’s Disease Centers (ADCs)
  • the Children’s Hospital of Philadelphia (CHOP)

ADGC seeks to identify genetic variability that influences susceptibility to AD. Susceptibility genes potentially influence age of onset and rate of progression through the prodromal and mild cognitive impairment (MCI) phases of the disease. In addition, ADGC looks for genes that influence specific ADrelated endophenotypes, such as neuropathology features (e.g., amyloid load, tangle load), biomarker measures (e.g., Aß and tau levels in cerebrospinal fluid, MRI measures), rate of disease progression, and responses to environmental factors (e.g., drugs, non-pharmaceutical environmental factors).

 

NACC's role

NACC maintains a large database of standardized data — the Uniform Data Set (UDS) — collected by the ADCs. NACC cleans and curates the data to ensure they are as complete as possible and makes them available for research. For the GWAS project, NACC provides each ADC with a list of its own subjects that are eligible for the GWAS, tracks which samples have been submitted for DNA banking, and then reimburses the ADCs for the cost of sending the DNA. NCRAD sends DNA out for genotyping; once the genotyping is complete, those data are sent to ADGC. Finally, NACC sends HIPAA researchlimited phenotypic data to ADGC, so that the phenotypic data can then be paired with the genotype data. The diagram below illustrates the process.