Genome-wide Association Study (GWAS)

• A large number of genetic variants-typically SNPs (hundreds of thousands to millions) are tested across many individuals to identify genotype-phenotype associations.
• Usually SNPs are analyzed, although other types of mutations are possible.
• The SNPs of controls and those with a particular disease are analyzed. GWAS looks for mutations which only occur in patients with that particular disease.

Benefits

• Effective at discovering SNV-trait associations.
• Has successfully identified mutations which increase risk for:
  • Major depressive disorder
  • Several types of cancers
  • Type 2 diabetes
  • Schizophrenia
  • and others…

Limitations

• It is challenging to determine whether or not there is a cause-and-effect relationship between mutations and phenotype.
• Limited to single-base mutations.
• SNPs are often markers of nearby regions of the genome where the disease-causing mutation lies—they may not themselves be responsible.