Tapping Crowd-Sourced Data Unearths Trove of Depression Genes

Scientists have discovered 15 genome sites—the first ever—linked to depression in people of European ancestry. Many of these regions of depression-linked genetic variation turn out to be involved in regulating gene expression and the birth of new neurons in the developing brain.

But, in a twist, the researchers didn’t have to sequence anyone’s genes. Instead, they analyzed data already shared by people who had purchased their own genetic profiles via an online service and elected to participate in its research option. This made it possible to leverage the statistical power of a huge sample size to detect weak genetic signals associated with a diagnosis likely traceable to multiple underlying illness processes.

This novel use of crowd-sourced data was confirmed with results from traditional genetics approaches in the study, funded by NIH.

Dr. Roy Perlis of Harvard/Massachusetts General Hospital, a grantee of NIMH and NHGRI, and colleagues from industry reported on their findings Aug. 1 in the journal Nature Genetics.

It’s well known that at least some depression runs in families and some risk is inherited. Yet, prior to this study, conventional genome-wide approaches had failed to reliably identify chromosomal sites associated with the illness in populations with European roots. Since depression is thought to be like fever—a common set of symptoms likely rooted in multiple causes—lumping together genetic data from people with different underlying illness processes likely washed out, or statistically diluted, subtle evidence of effects caused by risk genes.

To increase their odds of detecting these weak genetic signals, the researchers adopted a strategy of studying much larger samples than had been used in the earlier genome-wide studies. They first analyzed common genetic variation in 75,607 people of European ancestry who self-reported being diagnosed or treated for depression and 231,747 healthy controls of similar ethnicity. These data had been shared by people who purchased their own genetic profiles via the 23 and Me web site and agreed to participate in the company’s optional research initiative, which makes data available to the scientific community while protecting privacy.