Nowadays, everyone’s a walking risk factor for one sort of disease or another. Do we want to know if we’re at increased risk for ovarian cancer? Or for Lou Gehrig’s disease? While some may be shaking their heads “no,” others want to be privy of their risk factors for such diseases -- which is where direct-to-consumer (DTC) genetic testing steps in.
DTC testing, in the most basic sense, evaluates consumers’ genes for susceptibility of a plethora of health-related conditions by way of a kit and some spit. Order a mail kit online from a number of the DTC companies found on the web, spit into a tube and then have your saliva analyzed by lab experts. Once your DNA has been processed, companies like 23andMe allow consumers to log into the computer to explore their genome.
Some of the tests that DTC companies provide check for traits that range from the weird and the gross, like asparagus metabolite detection and earwax type, to the more serious, like HIV progression. 23andMe also provides consumers with results pertaining to their drug response and carrier status as well as risk to diseases.
Controversy over DTC testing is prevalent, because average consumers aren’t always equipped with the proper knowledge and understanding of test results. For example, certain gene alterations can put a person at an increased risk of developing a condition, such as breast cancer, but that doesn’t mean that a person is specifically going to develop it.
“The probabilities and odds that a DTC test might report to a consumer could lead to confusion or anxiety,” said Jessica Stransky of the genetic counseling program at the University of Maryland, Baltimore.
As Stransky further explains, if you’re a carrier for an autosomal recessive disease like cystic fibrosis, there is a 50/50 chance that you’ll pass it down to your child. However, consumers interpreting DTC data need to additionally understand that the child won’t be affected unless that person’s partner has and passes down that same trait.
“That kind of information is pretty hard for the average person to interpret,” said Stransky. “It gets more complicated with genetic traits that aren't highly linked to certain conditions. The concern is that consumers will adopt a kind of fatalistic attitude when they receive test results that put them at an increased risk for developing a disease.”
Still, supporters of DTC testing argue that consumers who find that they are at increased risk of, say, heart attack can alter their lifestyles in an attempt to prevent the likelihood of having one. Additionally, with the assistance of a knowledgeable doctor or genetic counselor, information on carrier testing can be useful for parents who are considering conceiving.
“Individuals can not only learn about their genetic ancestry from 23andMe, but they can also learn about their carrier status for 24 inheritable diseases such as cystic fibrosis,” said a 23andMe company spokesperson. “In other instances, knowing that you may have a higher than average risk for developing certain cancers can help facilitate conversations with your healthcare provider and the establishment of early screenings. For most cancers, early detection is key for effective treatment.”
Like with most things in life, including scientific technologies, there is a fine line between when enough is too much and when enough is just right. Even though debate looms over DTC testing, there’s controversy for a reason: both opponents and proponents are playing tug-of-genetic-war.