How do genome-wide association studies connect genetic variants with diseases?

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Diagram of a DNA double helix showing its twisted ladder structure, with a close-up of the sugar-phosphate backbone, paired nitrogenous bases (adenine, thymine, cytosine, guanine), and labeled nucleotides and hydrogen bonds. — human genome The human genome is made up of approximately three billion base pairs of deoxyribonucleic acid (DNA). The bases of DNA are adenine (A), thymine (T), guanine (G), and cytosine (C).

A genome-wide association study (GWAS) is a systematic method used to scan the human genome to identify links between genetic variations and specific diseases.1

Researchers primarily focus on single nucleotide polymorphisms (SNPs), which are common genetic variations. By analyzing large cohorts—often involving tens of thousands of individuals—scientists compare the genotypes of affected patients against healthy controls or examine traits that vary across populations.1

These studies utilize advanced technologies like microarray analysis or whole-genome sequencing to identify these variants. Once data is collected and quality-controlled, researchers look for statistically significant associations between specific SNPs and a disease. This process helps reveal the genetic underpinnings of complex conditions, such as schizophrenia, and supports advancements in personalized medicine by helping to predict disease risk and guide therapeutics.1

While powerful, GWAS results can be complex, as many identified variants contribute only minimally to disease risk, necessitating further research into underlying biological pathways.1