Explained What is DNA Test Genetic Testing Benefits of DNA Test
Explained What is DNA Test Genetic Testing Benefits of DNA Test
What is DNA?
Every cell in our bodies - from heart to skin, blood to bone - contains a complete set of our DNA.
At the heart of DNA testing is the molecule DNA.
DNA carries our genetic code and determines traits from eye color to aspects of our personalities.
99.9% of the DNA from two people will be identical.
The 0.1% of DNA code sequences that vary from person to person are what make us unique.
These sequences are called genetic markers, and are the part of the code that forensic scientists use when doing a DNA test.
The key to DNA testing is knowing where to look in the billions of letters of genetic code to find the genetic markers that will identify the important similarities or differences between people.
Our genetic code is made of 3 billion pairs
Genes are found in chromosomes and are made up of DNA. We inherit genes from our parents. Our gene structure dictates how our body grows and regulates.
When genes are normal, they work properly.
When genes are abnormal or damaged, they can lead to disease. These are called gene mutations, or changes. Some changes run in families (hereditary), and some happen by chance.
A gene mutation can be the sole cause of disease. However, most diseases occur from a mix of genetic and environmental factors.
What is genetic testing?
Genetic testing uses laboratory methods to look at your genes, which are the DNA instructions you inherit from your mother and your father. Genetic tests may be used to identify increased risks of health problems, to choose treatments, or to assess responses to treatments.
How is genetic testing done?
Genetic tests are usually requested by a person’s doctor or other health care provider. Although it may be possible to obtain some genetic tests without a health care provider’s order, this approach is not recommended because it does not give the patient the valuable opportunity to discuss this complicated decision with a knowledgeable professional.
Testing is done on a small sample of body fluid or tissue—usually blood, but sometimes saliva, cells from inside the cheek, skin cells, or amniotic fluid (the fluid surrounding a developing fetus).
The sample is then sent to a laboratory that specializes in genetic testing. The laboratory returns the test results to the doctor or genetic counselor who requested the test. In some cases, the laboratory may send the results to the patient directly. It usually takes several weeks or longer to get the test results.
Genetic counseling is recommended both before and after genetic testing to make sure that patients have accurate information about what a particular genetic test means for their health and care.
What is whole genome sequencing?
Whole genome sequencing is the mapping out of a person’s unique DNA. Your genome is the unique blueprint for your body.
Whole genome sequencing results can be placed into 3 categories –
1-Single-gene disorders (sometimes also called Mendelian disorders) are diseases that are caused by a mutation in the DNA for one gene. An example of these diseases is Sickle Cell Anemia .
2-Multi-factorial disorders are diseases associated with DNA changes in more than one gene. This often includes diseases like obesity and diabetes and often is highly influenced by your environment.
3-Pharmacogenomic profiles use an individual's genetic code to determine how they will respond to a drug so that a doctor can prescribe the correct amount. This is an example of personalized medicine.
This test helps the individual which medicine or drug will be more useful for him , which drug may harm his body. This test is useful for Sportsmen who want to stay fit and increase their performance in game.
Whole genome sequencing is different than gene sequencing. It is also different from whole exome sequencing which only looks at a person’s exons, the parts of DNA that code for proteins in the body.
What are at-home or direct-to-consumer genetic tests?
Some companies offer at-home genetic testing, also known as direct-to-consumer (DTC) genetic testing. People collect a tissue sample themselves and submit the sample through the mail. They learn about the test results online, by mail, or over the phone.
DTC genetic testing is often done without a doctor’s order or guidance from a doctor or genetic counselor before the test. Some states in the United States do not allow DTC genetic testing.
Whereas the genetic testing for cancer that is typically ordered by a doctor involves testing for rare major hereditary cancer syndromes, most DTC genetic testing for cancer risk involves the analysis of common inherited genetic variants, called single-nucleotide polymorphisms, that have been shown to be statistically associated with a particular type of cancer.
Even when people have DTC genetic tests for known mutations in genes associated with hereditary cancer syndromes, there are potential risks and drawbacks to the use of DTC testing.
In particular, without guidance about genetic test results from an informed, genetically knowledgeable health care provider, people may experience unneeded anxiety or false reassurance, or they may make important decisions about medical treatment or care based on incomplete information.
What are the different types of genetic tests?
1-Diagnostic testing is used to precisely identify the disease that is making a person ill. The results of a diagnostic test may help you make choices about how to treat or manage your health.
2-Predictive and pre-symptomatic genetic tests are used to find gene changes that increase a person's likelihood of developing diseases. The results of these tests provide you with information about your risk of developing a specific disease. Such information may be useful in decisions about your lifestyle and healthcare.
3-Carrier testing is used to find people who "carry" a change in a gene that is linked to disease. Carriers may show no signs of the disease; however, they have the ability to pass on the gene change to their children, who may develop the disease or become carriers themselves. Some diseases require a gene change to be inherited from both parents for the disease to occur. This type of testing usually is offered to people who have a family history of a specific inherited disease or who belong to certain ethnic groups that have a higher risk of specific inherited diseases.
4-Prenatal testing is offered during pregnancy to help identify fetuses that have certain diseases.
5-Newborn screening is used to test babies one or two days after birth to find out if they have certain diseases known to cause problems with health and development.
6-Pharmacogenomic testing gives information about how certain medicines are processed by an individual's body. This type of testing can help your healthcare provider choose the medicines that work best with your genetic makeup.
7-Research genetic testing is used to learn more about the contributions of genes to health and to disease. Sometimes the results may not be directly helpful to participants, but they may benefit others by helping researchers expand their understanding of the human body, health, and disease.
Genetic testing may be beneficial whether the test identifies a mutation or not. For some people, test results serve as a relief, eliminating some of the uncertainty surrounding their health. These results may also help doctors make recommendations for treatment or monitoring, and give people more information for making decisions about their and their family's health, allowing them to take steps to lower his/her chance of developing a disease. For example, as the result of such a finding, someone could be screened earlier and more frequently for the disease and/or could make changes to health habits like diet and exercise. Such a genetic test result can lower a person's feelings of uncertainty, and this information can also help people to make informed choices about their future, such as whether to have a baby.
Genetic tests can help to –
1-Diagnose disease
2-Identify gene changes that are responsible for an already diagnosed disease
3-Determine the severity of a disease
4-Guide doctors in deciding on the best medicine or treatment to use for certain individuals
5-Identify gene changes that may increase the risk to develop a disease-
6-Identify gene changes that could be passed on to children
7-Screen newborn babies for certain treatable conditions
Newborn screening –
Newborn screening is used just after birth to identify genetic disorders that can be treated early in life. Millions of babies are tested each year in the United States. All states currently test infants for phenylketonuria (a genetic disorder that causes intellectual disability if left untreated) and congenital hypothyroidism (a disorder of the thyroid gland). Most states also test for other genetic disorders.
Diagnostic testing –
Diagnostic testing is used to identify or rule out a specific genetic or chromosomal condition. In many cases, genetic testing is used to confirm a diagnosis when a particular condition is suspected based on physical signs and symptoms. Diagnostic testing can be performed before birth or at any time during a person's life, but is not available for all genes or all genetic conditions. The results of a diagnostic test can influence a person's choices about health care and the management of the disorder.
Prenatal testing –
Prenatal testing is used to detect changes in a fetus's genes or chromosomes before birth. This type of testing is offered during pregnancy if there is an increased risk that the baby will have a genetic or chromosomal disorder. In some cases, prenatal testing can lessen a couple's uncertainty or help them make decisions about a pregnancy. It cannot identify all possible inherited disorders and birth defects, however.
Forensic testing –
Forensic testing uses DNA sequences to identify an individual for legal purposes. Unlike the tests described above, forensic testing is not used to detect gene mutations associated with disease. This type of testing can identify crime or catastrophe victims, rule out or implicate a crime suspect, or establish biological relationships between people (for example, paternity).
How are genetic tests regulated?
U.S. laboratories that perform health-related testing, including genetic testing, are regulated under the Clinical Laboratory Improvement Amendments (CLIA) program. Laboratories that are certified under CLIA are required to meet federal standards for quality, accuracy, and reliability of tests. All laboratories that do genetic testing and share results must be CLIA certified. However, CLIA certification only indicates that appropriate laboratory quality control standards are being followed; it does not guarantee that a genetic test being done by a laboratory is medically useful.
Many people are worried about discrimination based on their genetic test results. In 2008, US Congress enacted the Genetic Information Nondiscrimination Act (GINA) to protect people from discrimination by their health insurance provider or employer.
Your genes don’t determine everything. They can tell you that you are at a higher risk of disease, but the personal choices you make and the environment in which you live still play a very important role. It is important to maintain a healthy lifestyle in order to minimize your risk of disease. The growing field of gene-environment research focuses on how your lifestyle and environment interact with your genes to affect your health.
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Sunday, November 12, 2017
Tags – DNA Testing Genetic Testing Benefits of DNA Test Genetic Fitness Blueprint
