You’re one of a kind. Wouldn’t it be nice if treatments and preventive care could be designed just for you, matched to your unique set of genes?
The story of personalized medicine begins with the unique set of genes you inherited from your parents. Genes are stretches of DNA that serve as a sort of instruction manual telling your body how to make the proteins and perform the other tasks that your body needs. These genetic instructions are written in varying patterns of only 4 different chemical “letters,” or bases.
The same genes often differ slightly between people. Bases may be switched, missing, or added here and there. Most of these variations have no effect on your health. But some can create unusual proteins that might boost your risk for certain diseases. Some variants can affect how well a medicine works in your body. Or they might cause a medicine to have different side effects in you than in someone else.
The study of how genes affect the way medicines work in your body is called pharmacogenomics.
“If doctors know your genes, they can predict drug response and incorporate this information into the medical decisions they make,” says Dr. Rochelle Long, a pharmacogenomics expert at NIH.
It’s becoming more common for doctors to test for gene variants before prescribing certain drugs. For example, children with leukemia might get the TPMT gene test to help doctors choose the right dosage of medicine to prevent toxic side effects. Some HIV-infected patients are severely allergic to treatment drugs, and genetic tests can help identify who can safely take the medicines.
“By screening to know who shouldn’t get certain drugs, we can prevent life-threatening side effects,” Long says.
Pharmacogenomics is also being used for cancer treatment. Some breast cancer drugs only work in women with particular genetic variations. If testing shows patients with advanced melanoma (skin cancer) have certain variants, 2 new approved drugs can treat them.