In this module students will learn about the concept of ‘personalized’ medicine; how differences in our genes affect whether a drug treatment will be successful or have serious side effects, and how we can use this information to customize treatments for individual patients. Students will participate in a hands-on activity to further demonstrate how subtle genetic differences affect a patient’s response to medication.
To introduce the concept of our genes impacting how we react to medicine, this module begins with a case study of a clinical trial for a new breast cancer drug called “tumoricide”. Ten women with breast cancer were given the drug which led to three getting better, six experiencing no change, and one developing a heart condition attributed to the drug. Why did this happen? This module will address this question in detail.
Changes in the DNA sequence for a gene can result in a direct change in the amino acid composition of the protein (remember DNA -> RNA -> protein), thus changing it’s shape and possibly it’s function. These changes can be due to natural variation or mutation by some external factor. Variations in genes can lead to changes in physical appearance, but in some cases can also lead to disease. Diseases that occur due to inherited genetic factors are called genetic diseases.
Drugs are chemicals that act like a specialized “key” that recognizes a specific receptor on cells in our body like a “lock”. Variations in our DNA can lead to variability in the shape or prevalence of our receptors which can have big impacts on how well (or not well) a drug works in our body. In addition, we all have differences in our metabolism that affects how quickly a drug is processed, and thus is active, in our bodies. This module will explore the individual nature of our responsiveness to drugs through an activity where students taste a non-toxic chemical called PTC. The ability to taste PTC is based both on the presence of a single allele of the PTC receptor and also on the number of taste buds an individual has. This demonstrates to students how there are multiple factors at play when thinking about how drugs interact with our bodies.
This module ends with a discussion of Pharmacogenomics, or personalized medicine. By understanding more about our DNA, scientists and doctors will be able to more accurately prescribe the correct medicines at the correct doses for each individual.