What is DNA testing / genetic testing ?
The human body is made up of billions of cells, the building blocks of the body. Each cell of the human body contains chemical information known as DNA (Deoxyribonucleic acid) that encodes the inherent physical and functional properties of the cell, and collectively defines who you are physically and how your body functions, behaves and responds to physiological and environmental cues. The DNA in each human cell is organized into structures known as chromosomes which help to maintain the integrity and function of DNA. Most cells of the human body have 23 pairs of chromosomes, with each inherited from your mother or father.
Each chromosome contains several thousand genes which are organized on the DNA and serve as codes or instructions to produce other molecules such as proteins, and essentially to provide instructions on how cells function, grow and establish the building blocks of the human body. Genetics is the study of inheritance, gene structure and function. Genetic testing, also known as DNA testing, is a test that identifies and reports changes in the genetic and sometimes protein function/content of biological specimens analyzed.
These changes in the DNA content or information can also be traced back to which parent it was inherited from on many occasions, and such could also influence the interpretation of genetic findings. With advances in technologies and in the science of genomics for medical applications, DNA testing / genetic testing could also be considered medical genetic testing, molecular diagnostic testing, genome medicine, or genomic medicine.
How is DNA testing / genetic testing done ?
DNA is extracted from biological specimens such blood, saliva, tissue biopsy and so on, and the genetic material is subjected to cutting edge DNA, chromosome, or genome analysis technologies to produce data which are then interpreted by experts in genetic data analysis (known as bioinformaticians) and by genetic specialists to make conclusions of the findings, and within the context of your health.
Sometimes, other than DNA, proteins or other biochemical molecules are analyzed from biological specimens and on many occasions, the findings can be supported and confirmed by DNA analysis. More than 5000 genes of the human genome are known to have clinical significance and/or medical relevance in responding to treatments. Such findings have led to the development of numerous DNA testing / genetic testing options for human disease diagnostic applications. Other than human, DNA testing / genetic testing can also be undertaken on any organism in which we have some knowledge of its genetics, gene function and DNA chemical information (known as DNA sequence information).
In general, the technologies and genetic testing strategies used to analyze human biological samples can be adequately used on most occasions to analyze non-human samples. An example is using DNA testing on human biological samples to extract genetic material from microorganisms and/or pathogens to diagnose infectious diseases in humans, or to establish relevance to your health.
What are the benefits of DNA testing / genetic testing ?
DNA testing / genetic testing has many benefits to offer you and your healthcare provider. Findings from DNA testing / genetic testing can help you and your healthcare provider:
1) confirm or exclude the suspected diagnosis of a genetic medical condition or illness you may have;
2) identify whether you could be a carrier and at high risk of transmitting a genetic medical condition or illness to your future child or children;
3) determine whether you are at high risk of developing a genetic medical condition or illness, such as cancer and heart disease, at a later age in your life;
4) establish whether you are biologically related to other people;
5) identify suitable medications that could better and more cost effectively treat your medical condition or illness;
6) determine whether someone is a suitable match to you for organ or tissue transplantation;
7) explain certain traits or features that you have;
8) make lifestyle and dietary changes for a healthier life;
9) make better reproductive and family planning decisions;
10) obtain better clinical care which could potentially delay or prevent the onset of some genetic medical conditions and could potentially lead to living a healthier and longer life.
Who should get DNA testing / genetic testing ? Is DNA testing / genetic testing a good idea for me ?
DNA testing / Genetic testing is voluntary, and a recommendation to have a DNA testing / genetic testing is determined on an individual basis. The most common criteria for DNA testing / genetic testing is whether the medical condition, illness or trait under investigation is already present in one or more of your biological family members, or there is well established clinical evidence that the medical condition, illness or trait has a genetic cause. In many occasions, some individuals would have classic clinical features or symptoms reminiscent of a genetic medical condition but such clinical features or symptoms are absent among their family members.
In this example, the medical condition is speculated to be sporadic or de novo in the individual, and DNA testing / genetic testing options can be used to determine more precisely the diagnosis of the medical condition or illness. If you are in the need for an organ or tissue transplantation, DNA testing / genetic testing can also provide more precise matching of individuals for such transplantation. Furthermore, if your current medications have adverse side effects, such as inducing allergic reactions, or are too expensive or are not effectively treating your medical condition or illness, DNA testing / genetic testing can help you find more suitable medications. Other than for medical applications, DNA testing / genetic testing can also be used to help you determine if you are biologically related to someone, and to establish the extent of relatedness and ancestry.
Apart from the numerous benefits of DNA testing / genetic testing has to offer you, it does have limitations and risks. Therefore, it is important for you to discuss with your healthcare provider the psycho-social, and pros and cons of DNA testing / genetic testing prior to pursuing such testing option. For instance, if you are a healthy person, a positive result from a DNA test / genetic test does not necessarily mean you will develop a medical condition, or if you do there could be variations in the severity of the symptoms of a medical condition where you only get very mild symptoms. If your DNA test / genetic test results show you are negative for a medical condition or illness, it does not guarantee that you do not have or would develop such medical condition since other factors could potentially also cause the same medical condition. It must also be noted that the Genetic Information Nondiscrimination ActMolecular genetic testing (GINA) generally prevents health insurance providers from discriminating against you based on your DNA testing / genetic testing results. You should contact your local provincial/state representatives to learn how you are protected by GINA.
What are the types of DNA testing / genetic testing ?
Within the context of DNA testing / genetic testing of humans, there are many medical applications that can be undertaken, and each type of DNA testing / genetic testing application is done in a different manner. Some of these DNA testing / genetic testing applications include:
1) Molecular genetic testing:
This is a type of DNA testing / genetic testing to analyze parts of a gene, single genes or sometimes panels of genes to identify mutations that could be associated with your medical condition or illness. This type of testing can identify single mutation variants, gene repeat mutations, DNA modification mutations (known as methylation or epigenetic mutations), small copy number changes within a gene, aberrancies in how a gene or assortment of genes are inherited from a parent (known as uniparental disomy mutations), and so on.
2) Cytogenetic testing: This is a type of DNA testing /genetic testing to analyze large segments of DNA in the form of chromosomes to determine if there are any changes such as gross gain or loss of chromosome content, fusions between two different chromosomes, other complex chromosome aberrations and so on, that could be associated with your medical condition or illness. Cytogenetic testing is most often recommended if you have symptoms including developmental, movement, speech, or learning problems.
3) Biochemical genetic testing: This is a type of genetic testing that analyzes proteins or biochemical molecules produced by cells, to determine if there are any aberrancies that could be associated with your medical condition, metabolic condition or illness. Confirmation of these biochemical genetic findings is often followed up by molecular genetic testing.
4) Personal genome testing: With the recent availability of cutting edge genome analysis technologies, it has made possible very cost effective and efficient analysis of all genes (known as exome analysis), as well as complete genomes (known as whole genome analysis). This type of DNA testing / genetic testing investigates all genes or complete DNA of a person and correlates findings with an associated medical condition, illness or trait. It is currently the most thorough examination available to provide you a blueprint of genetic insights into your DNA.
5) Carrier genetic testing or Pan ethnic carrier genetic testing: This is a type of DNA testing / genetic testing to determine if you are a carrier of a genetic disorder, and is recommended for family planning. This type of test focuses more on what is called genetic conditions which are associated with recessive inheritance, in which on most occasions two defective copies of a gene need to be inherited from both parents. Individuals tend to be asymptomatic or have no symptoms if they are a carrier for most of these genetic disorders, but if the genetic mutation(s) is transmitted by both parents to the child, then a medical condition or illness could manifest fully in their child. It is highly recommended if you belong to an ethnic group or have a family history of a genetic disorder, to have this type of DNA testing / genetic testing done before you start a family.
6) Presymptomatic genetic testing: This type of DNA testing / genetic testing is recommended if you have a family history of a genetic medical condition or illness but with no current symptoms yet. This test is used to detect if you have any genetic findings associated with such medical condition or illness. Often, the testing results could be used to delay or even prevent the onset of such medical condition or illness; obtain better clinical care with your healthcare providers; or plan changes in your lifestyle and dietary habits.
7) Predictive genetic testing: This type of DNA testing / genetic testing is used to determine if you as a healthy individual with or without a family history, could develop certain genetic medical conditions or illnesses. It examines the potential for developing medical conditions during adulthood, such as cancer, heart disease and so on. The testing results could be used to receive better clinical care with your healthcare providers to delay or even prevent the onset of the medical condition, as well as to make changes to your lifestyle and dietary habits.
8) Newborn screen genetic testing: This is a type of DNA testing / genetic testing which uses combined biochemical and molecular genetic techniques to screen newborn babies for very common genetic medical and metabolic conditions prevalent in the population. The majority of these genetic disorders screened are treatable when detected early in the infant, and therefore reinforces the importance of this type of DNA testing / genetic testing for your newborn infant.
9) Prenatal genetic testing: This type of DNA testing / genetic testing investigates genetic material harvested from your developing fetus for a suspected genetic medical condition. Invasive prenatal genetic testing requires the analysis of fetal material which is extracted from the expectant mother in procedures known as amniocentesis, percutaneous umbilical blood sampling, or chorionic villus sampling. On the other hand, non-invasive prenatal testing involves the analysis of fetal material known as fetal circulating free DNA which is extracted from the venous blood of an expectant mother. This method is currently used often to screen for Downs syndrome, and other common chromosome aberrancies, if you are an expectant mother. However, because the yield and integrity of fetal DNA harvested from non-invasive procedures is generally significantly lower than fetal DNA harvested from using invasive procedures, there are some limitations regarding the extent of testing that can be done with fetal circulating free DNA. Despite this, non-invasive prenatal genetic testing provides several prominent advantages including making prenatal genetic testing feasible as early as 10 weeks of the pregnancy, and only requiring venous blood from the expectant mother without harming the developing fetus from invasive procedures.
10) Preimplantation genetic testing: This is a type of DNA testing / genetic testing to identify genetic problems very early within embryos that are created by in vitro fertilization (IVF), before an official pregnancy starts. This test can benefit you if you are a high risk couple, by lowering the risk or even preventing the transmission of certain known genetic condition(s) to your child. It could also eliminate your dilemma of pregnancy termination often associated with the unfavorable prenatal diagnosis of a genetic medical condition.
11) Pharmacogenomic genetic testing: This type of DNA testing / genetic testing examines the influence of certain mutations in your DNA and how they influence your body’s response to certain medications. This DNA testing / genetic testing information can be used to identify medications that are more suitable, potent, cost effective and have less adverse side effects for treating your medical conditions or illnesses.
12) Infectious disease DNA testing / genetic testing: This type of DNA testing / genetic testing identifies the presence or absence of genetic material associated with microorganisms or pathogens in human biological samples, and correlates such finding with the diagnosis your infection or how your health can be affected. Nucleic amplification test (NAAT), as well as clinical metagenomic tests are the most cutting edge methods with high sensitivity and accuracy for microorganism and pathogen detection, compared to prior conventional laboratory based methods for infectious disease diagnosis. Furthermore, clinical metagenomic testing offers the ability for the detection of rare to extremely rare pathogens and could be helpful to establish a diagnosis when your doctor is uncertain what is causing your infection.
13) Paternity / siblingship / relationship DNA testing: This is a type of DNA testing which uses a series of unique genetic markers of the human genome to establish with statistical certainty whether you are biologically related or not to other people. It could be important to support your diagnostic findings, when there is evidence of non-paternity or non-biological relationship from the DNA testing / genetic testing.
At CEN4GEN, we offer all of the above DNA testing / genetic testing options. To learn more about how our testing options can suit your needs, contact us at firstname.lastname@example.org, and a representative will guide you through the testing process and provide more information for you and your healthcare provider.
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