What is genetic testing and personalized medicine?
Genetic testing is a type of medical test that identifies changes in genes. Personalized medicine is a medical procedure that separates patients into different groups—with medical decisions, practices, interventions being tailored to the individual patient based on their genome and predicted response or risk of diseases. The results of a genetic test in personalized medicine can confirm or rule out a suspected genetic condition, help determine a person’s chance of developing a disease (genetic predisposition) or passing on a genetic disorder. Having genetic predisposition does not mean that a person will definitely develop the underlying disease, it just indicates that the individual has an increased/decreased chance of developing a disease. Genetic tests should be interpreted in combination with conventional medical diagnostic tests.
What is DNA?
Our bodies are made of trillions of cells. Inside each of those cells are chromosomes, and humans have 23 pairs of chromosomes. One chromosome of each pair comes from the mother and the other chromosome comes from the father. Each chromosome is composed of deoxyribonucleic acid (DNA). A simple analogy is that a person’s DNA serves as a blueprint for all of the information that makes us who we are. The DNA itself is organized into specific segments called genes, which encode proteins needed for the body to grow and function. The specific coding within the genes is composed through the use of only four specific DNA bases: A, T, G, and C.
Do all changes in DNA cause disease?
No, some changes in DNA are normal variations between humans, which do not cause disease. These types of changes are called benign variants. Alternatively, some changes in the DNA can lead to damaged or faulty genes, which in turn can disrupt the function of the proteins normally encoded by the DNA. These changes are called deleterious or pathogenic mutations.
How does cancer develop?
Cancer develops due to an accumulation of damaging DNA changes (mutations) in a single cell over an individual’s lifetime. Most of these changes happen as part of the natural aging process that our bodies go through over time (called somatic changes), while in rare instances some individuals are born with a mutation in all of their cells (called germline changes), which gives them a “head-start” to developing cancer in their lifetime.
What is hereditary cancer?
There are three categories of cancer: (1) Sporadic, (2) Familial/Multifactorial, and (3) Hereditary.
(1)Sporadic cancer is generally thought to be due a combination of environmental factors and natural aging process. (2) Familial/Multifactorial cancer generally refers to a history of cancer in families that cannot be attributed to a single gene mutation. Development of cancer in these families is likely due to a combination of mutations in multiple low risk or moderate risk cancer genes as well as environmental factors. (3) Hereditary cancer refers to cancer that is due to a single gene mutation that significantly increases an individual’s risk of certain cancers over their lifetime. Individuals are born with these singe gene mutations, and in most cases, they have been passed down from family members (inherited) for a number of generations.