When someone gets a genetic test for a rare form of diabetes, the result isn't always a clear 'yes' or 'no.' Sometimes it's a 'variant of uncertain significance'—a genetic change where we just don't know yet what it means for health. A new look at a massive public database of human genetics found that for many of the genes linked to monogenic diabetes, only about 30% of the known genetic variants have been classified at all in the main clinical database, ClinVar. That leaves a lot of unknowns on the table.
The researchers dug deeper to see if this uncertainty was spread evenly across people from different genetic backgrounds. They looked at over 14,600 variants across 17 key genes. They found that for variants common in people of African ancestry, the rate of these uncertain results was not statistically higher than for those of non-Finnish European ancestry. However, for all other non-European groups combined—including East Asian, South Asian, and others—the rate of uncertain results was significantly lower.
This is a database study, so it's observing patterns in existing information, not testing a new treatment. It doesn't tell us why these differences exist or what the health consequences are. One interesting twist was in a specific gene called GCK, where the uncertain rate was actually higher for non-European variants. The big takeaway is that the genetic playbook for diabetes is far from complete, and the chapter for many populations is particularly thin. More research is needed to fill in these blanks so that genetic testing can be equally informative for everyone.