The genes in your body’s cells play a key role in your health. Indeed, a defective gene or genes can make you sick.

Recognizing this, scientists have worked for decades on ways to modify genes or replace faulty genes with healthy ones to treat, cure, or prevent a disease or medical condition.

This research is paying off, as advancements in science and technology today are changing the way we define disease, develop drugs, and prescribe treatments.

The U.S. Food and Drug Administration has approved multiple gene therapy products for cancer and rare disease indications.

Genes, Cells, and How They Interact

Genes and cells are intimately related. Within the cells of our bodies, there are thousands of genes that provide the information to produce specific proteins that help make up the cells. Cells are the basic building blocks of all living things; the human body is composed of trillions of them.

The genes provide the information that makes different cells do different things. Groups of many cells make up the tissues and organs of the body, including muscles, bones, and blood. The tissues and organs in turn support all our body’s functions.

How Gene Therapy Works

Sometimes the whole or part of a gene is defective or missing from birth. This is typically referred to as a genetically inherited mutation.

In addition, healthy genes can change (mutate) over the course of our lives. These acquired mutations can be caused by environmental exposures. The good news is that most of these genetic changes (mutations) do not cause disease. But some inherited and acquired mutations can cause developmental disorders, neurological diseases, and cancer.

Depending on what is wrong, scientists can do one of several things in gene therapy:

• They can replace a gene that is missing or is causing a problem.
• They can add genes to the body to help treat disease.
• Or they can turn off genes that are causing problems.

To insert new genes directly into cells, scientists use a vehicle called a “vector.” Vectors are genetically engineered to deliver the necessary genes for treating the disease.

Vectors need to be able to efficiently deliver genetic material into cells, and there are different kinds of vectors. Viruses are currently the most commonly used vectors in gene therapies because they have a natural ability to deliver genetic material into cells. Before a virus can be used to carry therapeutic genes into human cells, it is modified to remove its ability to cause infectious disease.

Gene therapy can be used to modify cells inside or outside the body. When a gene therapy is used to modify cells inside the body, a doctor will inject the vector carrying the gene directly into the patient.

When gene therapy is used to modify cells outside the body, doctors take blood, bone marrow, or another tissue, and separate out specific cell types in the lab. The vector containing the desired gene is introduced into these cells. The cells are later injected into the patient, where the new gene is used to produce the desired effect.

Safety and Effectiveness of Gene Therapy

Before a gene therapy can be marketed for use in humans, the product must be tested in clinical studies for safety and effectiveness so FDA scientists can consider whether the risks of the therapy are acceptable considering the potential benefits.

The scientific field for gene therapy products is fast-paced and rapidly evolving – ushering in a new approach to the treatment of vision loss, cancer, and other serious and rare diseases. As scientists continue to make great strides in this therapy, the FDA is committed to helping speed up development by interacting with those developing products and through prompt review of groundbreaking treatments that have the potential to save lives.

Genes are the building blocks of inheritance. Passed from parent to child, they contain instructions for making proteins. If genes don't produce the right proteins or don't produce them correctly, a child can have a genetic disorder.

Gene therapy is an experimental technique that uses genes to treat or prevent disease. The most common form of gene therapy involves inserting a normal gene to replace an abnormal gene. Other approaches include

• Swapping an abnormal gene for a normal one
• Repairing an abnormal gene
• Altering the degree to which a gene is turned on or off

Although there is much hope for gene therapy, it is still experimental.

Human gene therapy seeks to modify or manipulate the expression of a gene or to alter the biological properties of living cells for therapeutic use.

Gene therapy is a technique that modifies a person’s genes to treat or cure disease. Gene therapies can work by several mechanisms:

• Replacing a disease-causing gene with a healthy copy of the gene
• Inactivating a disease-causing gene that is not functioning properly
• Introducing a new or modified gene into the body to help treat a disease

Gene therapy products are being studied to treat diseases including cancer, genetic diseases, and infectious diseases.

There are a variety of types of gene therapy products, including:

• Plasmid DNA: Circular DNA molecules can be genetically engineered to carry therapeutic genes into human cells.
• Viral vectors: Viruses have a natural ability to deliver genetic material into cells, and therefore some gene therapy products are derived from viruses. Once viruses have been modified to remove their ability to cause infectious disease, these modified viruses can be used as vectors (vehicles) to carry therapeutic genes into human cells.
• Bacterial vectors: Bacteria can be modified to prevent them from causing infectious disease and then used as vectors (vehicles) to carry therapeutic genes into human tissues.
• Human gene editing technology: The goals of gene editing are to disrupt harmful genes or to repair mutated genes.
• Patient-derived cellular gene therapy products: Cells are removed from the patient, genetically modified (often using a viral vector) and then returned to the patient.

Gene therapy products are biological products regulated by the FDA’s Center for Biologics Evaluation and Research (CBER). Clinical studies in humans require the submission of an investigational new drug application (IND) prior to initiating clinical studies in the United States. Marketing a gene therapy product requires submission and approval of a biologics license application (BLA).

Gene therapy works by altering the genetic code to recover the functions of critical proteins. Proteins are the workhorses of the cell and the structural basis of the body’s tissues. The instructions for making proteins are carried in a person’s genetic code, and variants (or mutations) in this code can impact the production or function of proteins that may be critical to how the body works. Fixing or compensating for disease-causing genetic changes may recover the role of these important proteins and allow the body to function as expected.

Gene therapy can compensate for genetic alterations in a couple different ways.

• Gene transfer therapy introduces new genetic material into cells. If an altered gene causes a necessary protein to be faulty or missing, gene transfer therapy can introduce a normal copy of the gene to recover the function of the protein. Alternatively, the therapy can introduce a different gene that provides instructions for a protein that helps the cell function normally, despite the genetic alteration.
• Genome editing is a newer technique that may potentially be used for gene therapy. Instead of adding new genetic material, genome editing introduces gene-editing tools that can change the existing DNA in the cell. Genome editing technologies allow genetic material to be added, removed, or altered at precise locations in the genome. CRISPR-Cas9 is a well-known type of genome editing.

Genetic material or gene-editing tools that are inserted directly into a cell usually do not function. Instead, a carrier called a vector is genetically engineered to carry and deliver the material. Certain viruses are used as vectors because they can deliver the material by infecting the cell. The viruses are modified so they can't cause disease when used in people. Some types of virus, such as retroviruses, integrate their genetic material (including the new gene) into a chromosome in the human cell. Other viruses, such as adenoviruses, introduce their DNA into the nucleus of the cell, but the DNA is not integrated into a chromosome. Viruses can also deliver the gene-editing tools to the nucleus of the cell.

The vector can be injected or given intravenously (by IV) directly into a specific tissue in the body, where it is taken up by individual cells. Alternately, a sample of the patient's cells can be removed and exposed to the vector in a laboratory setting. The cells containing the vector are then returned to the patient. If the treatment is successful, the new gene delivered by the vector will make a functioning protein or the editing molecules will correct a DNA error and restore protein function.

Gene therapy with viral vectors has been successful, but it does carry some risk. Sometimes the virus triggers a dangerous immune response. In addition, vectors that integrate the genetic material into a chromosome can cause errors that lead to cancer. Researchers are developing newer technologies that can deliver genetic material or gene-editing tools without using viruses. One such technique uses special structures called nanoparticles as vectors to deliver the genetic material or gene-editing components into cells. Nanoparticles are incredibly small structures that have been developed for many uses. For gene therapy, these tiny particles are designed with specific characteristics to target them to particular cell types. Nanoparticles are less likely to cause immune reactions than viral vectors, and they are easier to design and modify for specific purposes.

Researchers continue to work to overcome the many technical challenges of gene therapy. For example, scientists are finding better ways to deliver genes or gene-editing tools and target them to particular cells. They are also working to more precisely control when the treatment is functional in the body.

A new gene is inserted directly into a cell. A carrier called a vector is genetically engineered to deliver the gene. An adenovirus introduces the DNA into the nucleus of the cell, but the DNA is not integrated into a chromosome.

Genetic therapies may use gene transfer or genome editing approaches to change the DNA in a patient’s cells to treat a condition.

Gene transfer

Gene transfer introduces an additional gene into specific cells. This gene may stay as an extra piece of DNA in the cell or be inserted into the cell’s own chromosomes to become part of the cell’s own DNA.

A molecular package called a vector carries the gene to the cell nucleus, the central part of the cell where DNA is packaged in chromosomes. Vectors are created in the laboratory, often from viruses that have been modified to remove viral genes that cause disease and to carry a treatment gene.

Once the gene is inside the nucleus, the cell will start to make the critical protein needed for the cell to work properly. The new proteins make up for missing or faulty proteins and are meant to improve health for people who receive genetic therapies.

Genome editing

Genome editing introduces components that work together into cells. One component is a protein that cuts DNA, similar to a pair of molecular scissors. Another component is a guide molecule that can stick to DNA at specific sites. When the guide molecule sticks to an area of faulty DNA, the scissors protein attaches to the guide molecule and cuts out the faulty DNA.

After the target DNA is cut, several things can happen. The cell may leave behind a gap, return the DNA to its original state, or fill in this gap with the corrected DNA. The cell can fill in the corrected DNA if it has a template DNA to direct the cell to rebuild a healthier version of the DNA that was removed. Therefore, sometimes a small piece of template DNA is introduced as a third component. This DNA is a corrected version of the faulty DNA, and it is used to rebuild the DNA correctly after it is cut open.

Several treatments have been developed that involve genetic material but are typically not considered gene therapy. Some of these methods alter DNA for a slightly different use than gene therapy. Others do not alter genes themselves, but they change whether or how a gene’s instructions are carried out to make proteins.

Cell-based gene therapy

CAR T cell therapy (or chimeric antigen receptor T cell therapy) is an example of cell-based gene therapy. This type of treatment combines the technologies of gene therapy and cell therapy. Cell therapy introduces cells to the body that have a particular function to help treat a disease. In cell-based gene therapy, the cells have been genetically altered to give them the special function. CAR T cell therapy introduces a gene to a person’s T cells, which are a type of immune cell. This gene provides instructions for making a protein, called the chimeric antigen receptor (CAR), that attaches to cancer cells. The modified immune cells can specifically attack cancer cells.

RNA therapy

Several techniques, called RNA therapies, use pieces of RNA, which is a type of genetic material similar to DNA, to help treat a disorder. In many of these techniques, the pieces of RNA interact with a molecule called messenger RNA (or mRNA for short). In cells, mRNA uses the information in genes to create a blueprint for making proteins. By interacting with mRNA, these therapies influence how much protein is produced from a gene, which can compensate for the effects of a genetic alteration. Examples of these RNA therapies include antisense oligonucleotide (ASO), small interfering RNA (siRNA), and microRNA (miRNA) therapies. An RNA therapy called RNA aptamer therapy introduces small pieces of RNA that attach directly to proteins to alter their function.

Epigenetic therapy

Another gene-related therapy, called epigenetic therapy, affects epigenetic changes in cells. Epigenetic changes are specific modifications (often called “tags”) attached to DNA that control whether genes are turned on or off. Abnormal patterns of epigenetic modifications alter gene activity and, subsequently, protein production. Epigenetic therapies are used to correct epigenetic errors that underlie genetic disorders.

Vaccines help prepare the body to fight foreign invaders (pathogens such as bacteria or viruses), to prevent infection. All vaccines introduce into the body a harmless piece of a particular bacteria or virus, triggering an immune response. Most vaccines contain a weakened or killed bacteria or virus. However, scientists have developed a new type of vaccine that uses a molecule called messenger RNA (or mRNA for short) rather than part of an actual bacteria or virus. Messenger RNA is a type of RNA that is necessary for protein production. In cells, mRNA uses the information in genes to create a blueprint for making proteins. Once cells finish making a protein, they quickly break down the mRNA. mRNA from vaccines does not enter the nucleus and does not alter DNA.

mRNA vaccines work by introducing a piece of mRNA that corresponds to a viral protein, usually a small piece of a protein found on the virus’s outer membrane. (Individuals who get an mRNA vaccine are not exposed to the virus, nor can they become infected by the vaccine.) Using this mRNA blueprint, cells produce the viral protein. As part of a normal immune response, the immune system recognizes that the protein is foreign and produces specialized proteins called antibodies. Antibodies help protect the body against infection by recognizing individual viruses or other pathogens, attaching to them, and marking the pathogens for destruction. Once produced, antibodies remain in the body, even after the body has rid itself of the pathogen, so that the immune system can quickly respond if exposed again. If a person is exposed to a virus after receiving mRNA vaccination for it, antibodies can quickly recognize it, attach to it, and mark it for destruction before it can cause serious illness.

Like all vaccines in the United States, mRNA vaccines require authorization or approval from the Food and Drug Administration (FDA) before they can be used. Currently vaccines for COVID-19, the disease caused by the SARS-CoV-2 coronavirus, are the only authorized or approved mRNA vaccines. These vaccines use mRNA that directs cells to produce copies of a protein on the outside of the coronavirus known as the “spike protein”. Researchers are studying how mRNA might be used to develop vaccines for additional infectious diseases.

Blood and immune conditions

If you have a blood or immune condition, the doctor may take blood from your veins or bone marrow from your hip bone to be modified in a laboratory with genetic therapy. Blood and bone marrow contain hematopoietic stem cells, which produce other key cells that make up the blood and immune system.

In the laboratory, scientists may use either gene transfer or genome editing to change the sample of stem cells provided by you. The modified cells are returned to your body through an intravenous (IV) line in one of your blood vessels. This procedure is called cell-based therapy or a blood and bone marrow transplant. The altered hematopoietic stem cells will produce healthy blood or immune cells.

Genetic therapies for sickle cell disease are examples of how this approach is being developed. Currently, a blood and bone marrow transplant of stem cells from a relative or an unrelated well-matched donor can cure sickle cell disease, but many patients do not have a well-matched donor available. Genetic therapies that modify a person’s own hematopoietic stem cells may provide a cure for people who do not have a well-matched donor. Modified hematopoietic stem cells can be injected into the blood, then the cells travel in the bloodstream to the marrow spaces inside the bones. Once inside the bone marrow, the cells can produce healthy red blood cells that do not sickle. Watch the video below to learn more about how genome editing is being tested for sickle cell disease.

Treatments for organs or tissues

Sometimes, genetic therapies are needed to alter cells that cannot be easily removed from the patient for treatment in the laboratory. Researchers are still working on ways to deliver the genetic therapy for these conditions. The methods being studied include IV infusion into the bloodstream, injection directly into an organ, and other ways to directly deliver the therapy into the affected tissues.

One condition that could be treated this way is hemophilia B. Hemophilia is caused by a faulty gene that prevents production of a protein necessary to clot the blood after an injury. Genetic therapy that is being developed for Hemophilia B involves infusing a vector carrying the normal clotting factor gene into the bloodstream. The vector then reaches liver cells to produce the clotting factor needed for better health.

Gene therapy is currently available primarily in a research setting. The U.S. Food and Drug Administration (FDA) has approved only a small number of gene therapy products for sale in the United States. For example, FDA-approved gene therapies are available for conditions that include a rare eye disorder called Leber congenital amaurosis, a form of skin cancer known as melanoma, and a genetic muscle condition called spinal muscular atrophy. Other genetic therapies have been approved for blood cell cancers such as lymphoma and multiple myeloma. Gene therapies to treat additional conditions have been approved in other countries.

Hundreds of research studies (clinical trials) are under way to test gene therapy as a treatment for genetic conditions, cancer, and HIV/AIDS. If you are interested in participating in a clinical trial, talk with your doctor or a genetics professional about how to participate.

Below is a list of licensed products from the Office of Tissues and Advanced Therapies (OTAT).

• ABECMA (idecabtagene vicleucel)
  Celgene Corporation, a Bristol-Myers Squibb Company
• ALLOCORD (HPC, Cord Blood)
  SSM Cardinal Glennon Children's Medical Center
• BREYANZI
  Juno Therapeutics, Inc., a Bristol-Myers Squibb Company
• CARVYKTI (ciltacabtagene autoleucel)
  Janssen Biotech, Inc.
• CLEVECORD (HPC Cord Blood)
  Cleveland Cord Blood Center
• Ducord, HPC Cord Blood
  Duke University School of Medicine
• GINTUIT (Allogeneic Cultured Keratinocytes and Fibroblasts in Bovine Collagen)
  Organogenesis Incorporated
• HEMACORD (HPC, cord blood)
  New York Blood Center
• HPC, Cord Blood
  Clinimmune Labs, University of Colorado Cord Blood Bank
• HPC, Cord Blood - MD Anderson Cord Blood Bank
  MD Anderson Cord Blood Bank
• HPC, Cord Blood - LifeSouth
  LifeSouth Community Blood Centers, Inc.
• HPC, Cord Blood - Bloodworks
  Bloodworks
• IMLYGIC (talimogene laherparepvec)
  BioVex, Inc., a subsidiary of Amgen Inc.
• KYMRIAH (tisagenlecleucel)
  Novartis Pharmaceuticals Corporation
• LAVIV (Azficel-T)
  Fibrocell Technologies
• LUXTURNA
  Spark Therapeutics, Inc.
• MACI (Autologous Cultured Chondrocytes on a Porcine Collagen Membrane)
  Vericel Corp.
• PROVENGE (sipuleucel-T)
  Dendreon Corp.
• RETHYMIC
  Enzyvant Therapeutics GmbH
• STRATAGRAFT
  Stratatech Corporation
• TECARTUS (brexucabtagene autoleucel)
  Kite Pharma, Inc.
• YESCARTA (axicabtagene ciloleucel)
  Kite Pharma, Incorporated
• ZYNTEGLO (betibeglogene autotemcel)
  bluebird bio, Inc.
• ZOLGENSMA (onasemnogene abeparvovec-xioi)
  Novartis Gene Therapies, Inc.

Several treatments have been developed that involve genetic material but are typically not considered gene therapy. Some of these methods alter DNA for a slightly different use than gene therapy. Others do not alter genes themselves, but they change whether or how a gene’s instructions are carried out to make proteins.

Cell-based gene therapy

CAR T cell therapy (or chimeric antigen receptor T cell therapy) is an example of cell-based gene therapy. This type of treatment combines the technologies of gene therapy and cell therapy. Cell therapy introduces cells to the body that have a particular function to help treat a disease. In cell-based gene therapy, the cells have been genetically altered to give them the special function. CAR T cell therapy introduces a gene to a person’s T cells, which are a type of immune cell. This gene provides instructions for making a protein, called the chimeric antigen receptor (CAR), that attaches to cancer cells. The modified immune cells can specifically attack cancer cells.

RNA therapy

Several techniques, called RNA therapies, use pieces of RNA, which is a type of genetic material similar to DNA, to help treat a disorder. In many of these techniques, the pieces of RNA interact with a molecule called messenger RNA (or mRNA for short). In cells, mRNA uses the information in genes to create a blueprint for making proteins. By interacting with mRNA, these therapies influence how much protein is produced from a gene, which can compensate for the effects of a genetic alteration. Examples of these RNA therapies include antisense oligonucleotide (ASO), small interfering RNA (siRNA), and microRNA (miRNA) therapies. An RNA therapy called RNA aptamer therapy introduces small pieces of RNA that attach directly to proteins to alter their function.

Epigenetic therapy

Another gene-related therapy, called epigenetic therapy, affects epigenetic changes in cells. Epigenetic changes are specific modifications (often called “tags”) attached to DNA that control whether genes are turned on or off. Abnormal patterns of epigenetic modifications alter gene activity and, subsequently, protein production. Epigenetic therapies are used to correct epigenetic errors that underlie genetic disorders.

Genetic therapies are still in the early stages of research, development, and clinical trials, but researchers already know a lot about how they may work as a treatment. For example, if you participate in a clinical trial or receive genetic therapy in the future, treatment may be provided in one of two ways. Your cells may be directly modified inside your body, or your cells may be collected and modified outside your body and then returned to you. The method may depend on your condition and what organ or types of cells in your body need to be treated.

Benefits

In the future, genetic therapies may be used to prevent, treat, or cure certain inherited disorders, such as cystic fibrosis, alpha-1 antitrypsin deficiency, hemophilia, beta thalassemia, and sickle cell disease. They also may be used to treat cancers or infections, including HIV.

Genetic therapies that are currently approved by the FDA are available for people who have Leber congenital amaurosis, a rare inherited condition that leads to blindness. CAR T-cell therapy is FDA approved for people who have blood cancers, such as acute lymphoblastic leukemia (ALL) and diffuse large B-cell lymphoma.

Risks

Genetic therapies hold promise to treat many diseases, but they are still new approaches to treatment and may have risks. Potential risks could include certain types of cancer, allergic reactions, or damage to organs or tissues if an injection is involved.

Recent advances have made genetic therapies much safer. Better safety has resulted in the FDA approving some gene transfer therapies for clinical use in the United States. There have been a few clinical studies on genome editing, but the approach is much newer than gene transfer. Researchers are still studying the risks.

The National Institutes of Health, which includes the NHLBI, does not perform or fund studies on genome editing targeting sperm, eggs, or embryos in humans. These changes would be passed on to the patient’s children and could have unanticipated effects.

The first gene therapy trial was run more than thirty years ago. The earliest studies showed that gene therapy could have very serious health risks, such as toxicity, inflammation, and cancer. Since then, researchers have studied the mechanisms and developed improved techniques that are less likely to cause dangerous immune reactions or cancer. Because gene therapy techniques are relatively new, some risks may be unpredictable; however, medical researchers, institutions, and regulatory agencies are working to ensure that gene therapy research, clinical trials, and approved treatments are as safe as possible.

Comprehensive federal laws, regulations, and guidelines help protect people who participate in research studies (called clinical trials). The U.S. Food and Drug Administration (FDA) regulates all gene therapy products in the United States and oversees research in this area. Researchers who wish to test an approach in a clinical trial must first obtain permission from the FDA. The FDA has the authority to reject or suspend clinical trials that are suspected of being unsafe for participants.

The National Institutes of Health (NIH) also plays an important role in ensuring the safety of gene therapy research. NIH provides guidelines for investigators and institutions (such as universities and hospitals) to follow when conducting clinical trials with gene therapy. These guidelines state that clinical trials at institutions receiving NIH funding for this type of research must be registered with the NIH Office of Biotechnology Activities. The protocol, or plan, for each clinical trial is then reviewed by the NIH Recombinant DNA Advisory Committee (RAC) to determine whether it raises medical, ethical, or safety issues that warrant further discussion at a RAC public meeting.

An Institutional Review Board (IRB) and an Institutional Biosafety Committee (IBC) must approve each gene therapy clinical trial before it can be carried out. An IRB is a committee of scientific and medical advisors and consumers that reviews all research within an institution. An IBC is a group that reviews and approves an institution's potentially hazardous research studies. Multiple levels of evaluation and oversight ensure that safety concerns are a top priority in the planning and carrying out of gene therapy research.

The clinical trial process occurs in three phases. Phase I studies determine if a treatment is safe for people and identify its side effects. Phase II studies determine if the treatment is effective, meaning whether it works. Phase III studies compare the new treatment to the current treatments available. Doctors want to know whether the new treatment works better or has fewer side effects than the standard treatment. The FDA reviews the results of the clinical trial. If it determines that the benefits of the new treatment outweigh the side effects, it approves the therapy, and doctors can use it to treat a disorder.

Successful clinical trials have led to the approval of a small number of gene therapies, including therapies to treat inherited disorders like spinal muscular atrophy and Leber congenital amaurosis.

Because gene therapy involves making changes to the body’s basic building blocks (DNA), it raises many unique ethical concerns. The ethical questions surrounding gene therapy and genome editing include:

• How can “good” and “bad” uses of these technologies be distinguished?

• Who decides which traits are normal and which constitute a disability or disorder?

• Will the high costs of gene therapy make it available only to the wealthy?

• Could the widespread use of gene therapy make society less accepting of people who are different?

• Should people be allowed to use gene therapy to enhance basic human traits such as height, intelligence, or athletic ability?

Current research on gene therapy treatment has focused on targeting body (somatic) cells such as bone marrow or blood cells. This type of genetic alteration cannot be passed to a person’s children. Gene therapy could be targeted to egg and sperm cells (germ cells), however, which would allow the genetic changes to be passed to future generations. This approach is known as germline gene therapy.

The idea of these germline alterations is controversial. While it could spare future generations in a family from having a particular genetic disorder, it might affect the development of a fetus in unexpected ways or have long-term side effects that are not yet known. Because people who would be affected by germline gene therapy are not yet born, they can’t choose whether to have the treatment. Because of these ethical concerns, the U.S. Government does not allow federal funds to be used for research on germline gene therapy in people.

Genetic research is creating new ways for people to take action and prevent disease and new ways to treat disease through personalized medicine.

Why is my family health history important?

We have known for a long time that common diseases like heart disease, asthma, cancer, and diabetes can run in families. Rare diseases like hemophilia, cystic fibrosis, and sickle cell anemia also run in families. For example, if a parent has high blood pressure, his or her child is more likely to have high blood pressure as an adult.

Learning about the health history of your family and sharing this information with your health care provider can help you learn whether you have an increased chance of getting some common diseases.

Your health care provider can then give you individualized and specific education about how to:

• Check regularly for the disease.

• Follow a healthy diet.

• Get regular exercise.

• Avoid smoking tobacco and too much alcohol.

• Get specific genetic testing that can help with diagnosis and treatment.

How do I find a genetic professional?

To help people use family history to improve their health, the U.S. Surgeon General started a national public health campaign called the U.S. Surgeon General's Family History Initiative. This goal of this campaign is to have all American families learn more about their family health history.

My Family Health Portrait is a tool from the U.S. Surgeon General's Family History Initiative that you can find on the Web. The tool helps you gather and organize your own family health history. You can find it in either English or Spanish. Using any computer with an Internet connection, you can build a drawing of your family tree and make a chart of your family health history. Both the chart and the drawing can be printed and shared with your family members or your health care provider.

Can knowing about genetics help treat disease?

Every year, more than two million Americans have serious side effects from prescription medicines and as many as one hundred thousand die. A "one-size-fits-all" approach to medicine might lead to some of these side effects, since all people are different. Genetic research is helping us figure out how individual people will respond to medicines. This type of research is called "pharmacogenetics" and "pharmagenomics."

How is genetic information used to treat disease?

A person's genetic makeup affects how their body breaks down certain medicines. Genetic testing can examine certain liver enzymes in a person to find out how their body breaks down and removes medicines from the body. Because these liver enzymes are less active in some people, they are less able to break down and get rid of some medicines. This can lead to serious side effects. This type of testing is being used to find the right dose of certain medicines, such as antidepressants that are used to treat some mental illnesses.

• There is now a test to find out whether a medicine called Herceptin will be an effective treatment in breast cancer. This test looks "estrogen receptors" in tumors.

• Children with a common type of childhood leukemia can be tested to find the right doses of chemotherapy treatment.

What are some concerns?

Some people have concerns about using genetic information in the treatment of disease. These concerns include:

• Tailor-made medicines might be more expensive

• Not everyone might have access to new treatments

• Keeping genetic information private

• Possible discrimination at work and from health insurance companies

• Need for more information about this type of medicine