User talk:Kurtdennison

Genetic testing and its future in medicine Researchers, through time, and a variety of tests, have been able to decode the human genome. “The present intent is to use the human genome in the same way as all other medical research knowledge is used- to develop new and better treatments for disease”(Wade, 2001). Laboratory testing techniques now are able to determine if a person has a genetic condition or disease, or if that person is likely to get the disease. Having been able to unlock this complete set of instructions that make up an organism (genome), consisting of all the genetic material in those organisms chromosomes (threadlike structures made of DNA molecules that contain the genes); researchers now can sort through newly-discovered genes in search of those that lead to disease. These discoveries have helped us develop a much clearer understanding and view of these diseases, and how we can treat them.

What is Genetic Testing?

Genetic testing is a voluntary type of medical test that can identify changes in chromosomes, genes or proteins. Every person carries two copies of every gene, one inherited from their mother, and one from their father. The humane genome is believed to contain around 30,000 – 50,000 of these genes. Genetic tests are also tests on blood and other tissues used to find changes that are associated with inherited disorders. This kind of testing is complex, and the results depend both on reliable laboratory procedures and accurate interpretation of results. People may have many different reasons for being tested or not being tested. Individuals may wish to be tested if: •	There is a family history of one specific disease. •	They show symptoms of a genetic disorder. •	They are concerned about passing on a genetic problem to their children. Consideration must be given to the probability of false positive, or false negative test results. Because of this probability, and that the testing has its benefits and limitations, the decision about whether or not to be tested is both a personal and complex one. For this reason, genetic counselors can provide information about the pros and cons of the test, and discuss the ethical, social and emotional aspects of testing. During this approximately two hour meeting, your genetic counselor will make sure your medical history is complete, help you understand what genetic testing may-or may not-tell you, and answer any questions you may have. Other topics that will be discussed are the specific testing procedures, including any safety concerns, how long it will take to receive test results (can be within a few weeks, to several months), and what those results mean. If the test results come back negative, that would be good and cause little to worry about, but a positive result can be very frightening, though it does not necessarily mean that you will develop a disease, or can it predict the severity of the disease. A positive result may just be the incentive you need to monitor your health more closely, and make the necessary lifestyle changes, along with early treatment, to live a more productive life.

The Human Genome Project

In 1990, the U.S Human Genome project began, and was planned to last for 15 years, but through rapid technological advances, it was completed 2 years earlier in 2003. This 13 year effort was coordinated by the U.S. Department of Energy and the National Institutes of Health. In its beginning the HGP welcomed the Welcome Trust (U.K.) as a major partner, and later additional contributions came from Japan, France, Germany, China, and others. Project goals were to: •	Identify all the approximately 30,000 to 50,000 genes in human DNA, •	Determine the sequences of the 3 billion chemical base pairs that make up human DNA, •	Store this information in data bases, •	Improve tools for data analysis, •	Transfer related technologies to the private sector, and •	Address the ethical, legal, and social issues (ELSI) that may arise from the project. To help obtain these goals, researchers also studied the genetic makeup of several nonhuman organisms. These organisms included Escherichia coli, fruit flies, and the laboratory mouse (Shon, 2001). The HGP recently announced that they had indeed sequenced all of the human chromosomes. This was a huge achievement, but still, the sequence does not tell researchers what the 30,000 to 50,000 genes actually do in the body. The researchers will now have to figure out what the genes do, and exactly what role these genes may play in disease. Once this is figured out, they can develop tests such as those listed below, to screen people who are at risk for these diseases, and start looking for a cure. This research will be of large benefit to those diseases that are the result of a single gene disorder, however, “the vast majority of human disease is polygenic in origin-that is, more than one gene is involved in the development of the disease” (DeSalle and Yudell, 2005). Though the tests cannot cure the disease, knowing what genes cause a given disease can help researchers understand what goes wrong in that disease, which can help the search for drugs or treatments that counteract the problem.

Types of Genetic Testing

There are several different types of genetic testing available; depending on what information a person may want to know. One of the most common types is carrier testing. This is the type of test taken to identify people who carry one copy of a gene mutation that, when present in two copies, causes a genetic disorder. This type of testing is offered to individuals who have a family history of a genetic disorder, and to people in certain ethnic groups with an increased risk of a specific genetic condition. Also, this test is used by couples that have a family history of recessive genetic disorders that are considering having children. Some of the more common tests include those for: cystic fibrosis, Tay - Sachs disease (an inherited disease characterized by mental and physical retardation), some of the cancers, Lou Gehrig’s disease, Gaucher’s disease, Charcot-Marie-Tooth disease (loss of feeling in ends of limbs) and sickle-cell trait (Hyde and Setaro, 2001). Another type of genetic test is used for prenatal testing. This is a genetic testing of the fetus, and used to detect changes is a fetus’s genes or chromosomes before birth. This test is performed during pregnancy if there is an increased risk that the baby will have a genetic or chromosomal disorder. It cannot however identify all possible inherited disorders and birth defects, but it can lesson a couple’s uncertainty or help them make decisions about a pregnancy. Down syndrome is one of the most common genetic diseases screened by this method. Following childbirth, a couple may elect to have a newborn screening done. This is used just after birth to identify genetic disorders that can be treated early in life. Tests of this type usually have a clear benefit to the newborn because treatment is available. Millions of babies are tested each year in the United States. All states currently test infants for the genetic disorder known as phenylketonuria (a disease that causes mental retardation), and congenital hypothyroidism (a disorder of the thyroid gland). Most states also test for other genetic disorders. Other types of genetic testing include: diagnostic testing, preimplantation testing, predictive and presymptomatic testing, and one that is used commonly used for legal purposes, forensic testing. In forensic testing, DNA (through strands of hair, drops of blood, or skin cells) results can be used to identify unique characteristics of an individual (NIH, 2006). This type of testing can identify crime or catastrophe victims ( the tsunami in Indonesia Dec. 2004, the events of 911, and the World Trade Tower victims), rule out or implicate a crime suspect, or establish biological relationships between people (for example, paternity).

Can your risk be changed?

Once you have been tested, and told that you have a genetic risk, does that mean that the disease is inevitable? Only in some cases like the Huntington’s disease, where you carry a mutated gene that causes the disease, there is little you can do to prevent it. But for other heritable diseases such as cancer, heart disease and hemochromatosis, you may be able to decrease your risk by taking preventative action. With cancer, someone that has a strong family history of melanoma or other skin cancer can reduce sun exposure, and wear protective clothing to reduce the risk of skin cancer. “Aggressive monitoring for and the removal of growths in the colon in people inheriting a gene for a type of colon cancer can prevent fatalities” (Hyde and Setaro, 2001). With heart disease, someone that has a strong family history of heart disease can follow a healthy diet and exercise program, perhaps in combination with certain medications, to reduce their risk of having a heart attack. Hemochromatosis (a metabolic disorder that causes increased absorption of iron): someone with a mutation in both copies of the hemochromatosis gene can greatly decrease their iron intake and have regular blood draws to reduce blood iron levels, and thus the risk of developing disease symptoms.

By knowing which genes are involved in disease (such as the three previously mentioned ones), researchers can develop better medical treatments and prevention strategies that are specific for those gene defects. Knowing their personal risks makes it possible for individuals to decrease their chance of developing the disease through lifestyle changes, more aggressive disease surveillance, and preventative medical treatments. In certain instances, we already have more personalized medicine because of the advances in genetics; in the future these medical benefits will only expand.

Personalized medicine is something that will be of great benefit in the future. Different people metabolize drugs differently. For example, drugs quickly leave the bloodstream in some people, and linger for a long time in other people. If doctors knew how each person’s body handled different drugs, they could prescribe the right amount of the right drug rather than having to “guess” as they do today. As researchers learn more about human genetics, doctors will be able to prescribe medications based on each individual patient’s genetics. Prescribing medication in this way is also called “pharmacogenomics.” Drugs in the future may not only be better targeted to the cause of the disease, but there may also be better choices for people who react to drugs in specific ways.

Social and ethical side effects

“Genomics, like almost all technology, has the potential to live up to its billing as a marvel of human ingenuity or to disillusion us by causing great injury and harm” (DeSalle and Yudell, 2005). We have been able to discuss what is genetic testing, the human Genome project, types of testing, and the human risks, but just as importantly we must discuss the social and ethical issues and concerns with genetic testing. “All stakeholders in the genomic revolution, from government regulators to scientists to citizens, must recognize the potential for damaging side effects and find ways, through the development of legislation, ethical guidelines, and cultural standards, to make sure that our genetic privacy is ensured, that genetic discrimination never comes to pass, and that eugenics remains an historical case study” (DeSalle and Yudell, 2005). Ethical issues experienced in the application of human genetics technologies are: •	The shared nature and ownership of genetic information. •	Limitations of genetic testing. •	Inappropriate applications of genetic testing. •	Discrimination potential. •	Setting boundaries in applications of the genetic technology. •	Forensic testing The two primary ethical concerns arising from the use of genetic technologies are: 1. Ensuring equitable sharing of the benefits of genetic technology throughout the world, and 2. maximizing the benefits vs. harms in each instance of use. Some laws are already in place to protect individuals from the misuse of their genetic information. Here in Colorado, when you go and visit the doctor, nurse, dentist, you’ll be asked to read and sign a form that outlines your medical privacy rights under the Health Insurance Portability and Accountability Act, or HIPAA. “This law will protect your genetic and other personal health information from being used or shared without your knowledge” (NIH, 2006). The above several issues will take time to resolve, but the fact that they are there, and that people are talking about them is a good thing. Hopefully, this will lead to more discussions, engage and alert the public more, and provide even more opportunities to produce greater technologies in our search for cures.

Conclusion

When we look back at all the achievements and accomplishments made through medicine it is astonishing. All of the different cures, operations and access to public health care have helped us find ways to prolong life, and have been invaluable, but they have all been built on the reaction to a disease, which at times have been ineffective, inefficient or even dangerous. Today as we move forward into the 21st century, medicine and public health care are coming together in new ways. “Greatly improved knowledge of human health and disease, the creation of medical care that is personalized to an individuals genome, and the responsibility to interpret and manage billions upon billions of base pairs of genomic information will all be a part of the coming transformation in medicine” (DeSalle and Yudell, 2005). Medicine will no longer be reactive, but pro-active. Information provided to us through research and genetic testing will be able to discover the genes responsible for the disease, and with early recognition, and treatment, the disease may be limited, stopped, or better, may never even take place. Kurtdennison (talk) 19:31, 2 May 2008 (UTC)