Major depressive disorder is a significant health problem, but its biological underpinnings aren’t well understood. That’s in part because there’s variability in both the disease’s symptoms and its heritability. A recent study published in Nature Genetics identified five independent gene variants from four genome regions that are associated with depression, raising hopes that we can get a better handle on the disorder.

The study used a meta analysis of data collected by consumer genetics company 23andMe as well as previously published studies of depression. These studies can identify regions of the chromosome—and sometimes individual genes—that are frequently inherited along with the disorder. A correlation can imply causation.

The most significantly associated gene was OFLM4, which encodes for olfactomedin-4, a protein that promotes tumor growth and cell adhesion. This gene has not been previously associated with any psychiatric disorders, but it is known to be expressed in some brain regions, including the amygdala and the temporal lobe.