A common misconception I hear about genetic testing

Is it really "one and done?"

“I already had this testing, so I don’t need it again.”

This is one of the most common phrases I hear from patients when it comes to all types of genetic testing panels, whether it’s regarding carrier screening, cancer risk, or general health screening.

While it’s true that our DNA doesn’t change, we’re living in a time where the test options and interpretation of genomic information are changing. And they’re changing rapidly.

New and improved testing options

If you’ve done genetic testing in the past, there could be a more comprehensive version of that test today.

More genes

Some newer tests (across all areas of genetics) include more genes than ever before. For example, carrier screening offerings have expanded from a handful of genes to hundreds in the last decade.

Better detection

As technology improves and costs decrease, the latest genetic tests often have better ways of detecting important changes within your DNA. (Meaning, they have an improved ability to identify risk.)

So even if you’ve been tested before, it’s worth asking your provider if there’s a more comprehensive version of that test available now.

Note: This especially comes up when a patient says, “I already did 23andMe.” While 23andMe has been great in many ways- expanding access to genetics, raising awareness, and identifying some individuals at risk- its coverage of medically important genetic variants is limited. That’s because it wasn’t designed to guide medical care.

Our understanding of your results can change

Within a single gene, there are hundreds to thousands of genetic variants (“mutations”) that could be identified.

Behind the scenes, laboratory scientists (now with the help of AI) classify each variant on a scale from benign (not concerning) to pathogenic (disease-causing). In other words, the lab will determine which variants within a gene are harmless and which lead to disease. Some variants are even classified as having uncertain impact (called variants of uncertain significance, or VUS). As more information becomes available, classification of a variant can change over time. A variant that was previously considered uncertain can be upgraded to disease-causing or downgraded to benign.

Here’s the catch: Not all variants get re-reviewed unless there's a trigger — many labs won't reclassify unless new evidence is submitted or the variant is reanalyzed as part of an update process. And when there is reclassification, most labs don’t have systems in place to inform you of these changes.

The takeaway? Check in with the ordering provider (or a genetics specialist) on a regular basis (I’d suggest annually) to ensure you have the latest interpretation of your genetic test results.

The future: one test, lifelong updates

To be clear: I see a future in which genetic testing is “one and done.” Where patients can elect to have their whole genome sequenced (with proper consent and counseling!) With AI, they will be automatically informed (and offered further counseling) when there is a clinically significant change in variant classification.

But… we’re not quite there yet.

This is the way I see the field progressing, and a future I hope to work toward. For now, if you’ve had genetic testing, check in with a genetic counselor!