(Part 1 of a 2-part series)
The genetic makeup of all human beings is 99.9 percent identical. Therefore, the remaining 0.1 percent holds important clues about how different people are impacted by the same environmental influences.
Many of the most deadly diseases we face (cancer, diabetes, heart disease, to name a few) have a genetic component to them. Who gets cancer, who doesn’t, who responds to certain treatments and who doesn’t, and why? These are the questions being studied in the fields of genetics and genomics.
What’s the difference between genetics and genomics?
Genetics and genomics both have roles to play in health and disease.
Genetics refers to the study of genes and their roles in the way specific traits or conditions are inherited, or passed down, from one generation to another. Genes are segments of DNA that carry the code to make proteins; proteins direct the functions of the body and the activity of the cells. Examples of genetic or inherited disorders include cystic fibrosis, Huntington's disease, and phenylketonuria (PKU).
Genetics helps us understand how hereditary conditions are inherited and passed down in families. Genetic profiles also help to identify people who carry a genetic predisposition towards certain diseases like diabetes, so they can be advised to modify their diet and lifestyle to delay or prevent the onset of disease. One genetic mutation can result in a life threatening disease. Recently, two therapies to address genetic mutations were approved by the FDA, and more are being developed.
Genomics describes the study of all of an individual’s genes (the genome, the entire DNA content that is present within one cell of an organism); including the way the genes interact with each other and with the environment. Genomics involves the scientific study of complex diseases that are usually caused by a combination of genetic and environmental factors, like heart disease, diabetes, asthma, and cancer.
Genomics is helping researchers discover why some people get sick from certain infections, environmental influences, and behaviors, while others don’t. Some people live a healthy lifestyle, with regular exercise, a well-balanced diet, and medical checkups, yet they die of a heart attack at age 45. On the other hand, there are people who smoke, don’t have regular physical activity, eat unhealthy food, and still live to be 100. Genomics may hold the key to understanding these differences.
Personalized medicines and treatments
The science of pharmacogenetics and pharmacogenomics has allowed for important advances in medicine, including personalized treatment strategies.
Pharmacogenetic study of the differences in peoples’ responses to medications due to variation in single genes considers the genetic information for specific drug receptors, and how drugs are transported and metabolized by the body. The objective is to develop personalized drug therapies that provide the best choice and dose of drugs for each person’s genetic profile.
Pharmacogenomics, while similar, typically involves the study of variations in multiple genes implicated in variability in drug response. Pharmacogenomics can examine the whole genome, rather than only single genes.
Pharmacogenetic and pharmacogenomic studies are leading to medicines that can be tailor-made and adapted to each person's specific genetic profile. Although a person's environment, diet, age, lifestyle, and overall state of health can also affect their medication response, having an understanding of their genetic makeup is a critical element for developing personalized drugs that work better and have fewer side effects in that individual than the one-size-fits-all approach.
Next month: some personalized therapies and how they work