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Genetic testing allows the genetic diagnosis of vulnerabilities to inherited diseases, and can also be used to determine a person's ancestry. Genetics (from Ancient Greek grc-Latn genetikos, “genitive” and that from grc-Latn genesis, “origin” a discipline of Biology, is Diagnosis is the identification by Process of elimination, of the nature of anything A disease is an abnormal condition of an organism that impairs bodily functions and can be deadly An ancestor is a Parent or ( recursively) the parent of an ancestor (i Normally, every person carries two copies of every gene, one inherited from their mother, one inherited from their father. History See also History of genetics The existence of genes was first suggested by Gregor Mendel (1822-1884 who in the 1860s studied inheritance The human genome is believed to contain around 20,000 - 25,000 genes. The human genome is the Genome of Homo sapiens, which is stored on 23 chromosome pairs In addition to studying chromosomes to the level of individual genes, genetic testing in a broader sense includes biochemical tests for the possible presence of genetic diseases, or mutant forms of genes associated with increased risk of developing genetic disorders. A chromosome is an organized structure of DNA and Protein that is found in cells. Biochemistry is the study of the chemical processes in living Organisms It deals with the Structure and function of cellular components such as Genetic testing identifies changes in chromosomes, genes, or proteins. A chromosome is an organized structure of DNA and Protein that is found in cells. Most of the time, testing is used to find changes that are associated with inherited disorders. The results of a genetic test can confirm or rule out a suspected genetic condition or help determine a person's chance developing or passing on a genetic disorder. A genetic disorder is a condition caused by abnormalities in Genes or Chromosomes While some diseases such as Cancer, are due to genetic abnormalities acquired Several hundred genetic tests are currently in use, and more are being developed.

Since genetic testing may open up ethical or psychological problems, genetic testing is often accompanied by genetic counseling. Genetic counseling is the process by which patients or relatives at risk of an inherited disorder are advised of the consequences and nature of the disorder the probability of developing

Contents

Types

Genetic testing is "the analysis of RNA, chromosomes (DNA), proteins, and certain metabolites in order to detect heritable disease-related genotypes, mutations, phenotypes, or karyotypes for clinical purposes " (Holtzman & Watson 1997). Ribonucleic acid ( RNA) is a Nucleic acid that consists of a long chain of Nucleotide units Deoxyribonucleic acid ( DNA) is a Nucleic acid that contains the genetic instructions used in the development and functioning of all known Metabolomics is the "systematic study of the unique chemical fingerprints that specific cellular processes leave behind" - specifically the study of their small-molecule metabolite The genotype is the genetic constitution of a cell an organism or an individual (i In biology mutations are changes to the Nucleotide sequence of the Genetic material of an organism A phenotype is any observable characteristic of an Organism, such as its morphology, Development, biochemical or physiological properties A karyotype is the characteristic Chromosome complement of a Eukaryote Species. It can provide information about a person's genes and chromosomes throughout life. The term person is used in Common sense to mean an individual Human being. Available types of testing include:

Medical procedure

Genetic testing is often done as part of a genetic consultation. Once a person decides to proceed with genetic testing, a medical geneticist, genetic counselor, primary care doctor, or specialist can order the test after obtaining informed consent. Informed consent is a legal condition whereby a person can be said to have given Consent based upon an appreciation and understanding of the facts implications

Genetic tests are performed on a sample of blood, hair, skin, amniotic fluid (the fluid that surrounds a fetus during pregnancy), or other tissue. Blood is a specialized Bodily fluid that delivers necessary substances to the body's cells such as nutrients and oxygen—and transports Waste products Hair is a keratinised protein filament that grows through the epidermis from follicles deep within the Dermis. The skin is the outer covering of living tissue of an animal (or plant Amniotic fluid or liquor amnii is the nourishing and protecting liquid contained by the Amnion of a pregnant woman For example, a medical procedure called a buccal smear uses a small brush or cotton swab to collect a sample of cells from the inside surface of the cheek. A medical procedure is a course of action intended to achieve a result in the care of patients used by medical or paramedical personnel The sample is sent to a laboratory where technicians look for specific changes in chromosomes, DNA, or proteins, depending on the suspected disorder. The laboratory reports the test results in writing to a person's doctor or genetic counselor.

Routine screening tests are done on a small blood sample, using a 'heel stick', by pricking the babies heel and blotting the blood on a special paper. Unlike other types of genetic testing, a parent will usually only receive the result if it is positive.

Interpreting results

The results of genetic tests are not always straightforward, which often makes them challenging to interpret and explain. When interpreting test results, healthcare professionals consider a person’s medical history, family history, and the type of genetic test that was done.

A positive test result means that the laboratory found a change in a particular gene, chromosome, or protein of interest. History See also History of genetics The existence of genes was first suggested by Gregor Mendel (1822-1884 who in the 1860s studied inheritance A chromosome is an organized structure of DNA and Protein that is found in cells. Proteins are large Organic compounds made of Amino acids arranged in a linear chain and joined together by Peptide bonds between the Carboxyl Depending on the purpose of the test, this result may confirm a diagnosis, indicate that a person is a carrier of a particular genetic mutation, identify an increased risk of developing a disease (such as cancer) in the future, or suggest a need for further testing. Cancer (medical term Malignant Neoplasm) is a class of Diseases in which a group of cells display uncontrolled Because family members have some genetic material in common, a positive test result may also have implications for certain blood relatives of the person undergoing testing. It is important to note that a positive result of a predictive or presymptomatic genetic test usually cannot establish the exact risk of developing a disorder. Also, health professionals typically cannot use a positive test result to predict the course or severity of a condition.

A negative test result means that the laboratory did not find a dangerous copy of the gene, chromosome, or protein under consideration. This result can indicate that a person is not affected by a particular disorder, is not a carrier of a specific genetic mutation, or does not have an increased risk of developing a certain disease. It is possible, however, that the test missed a disease-causing genetic alteration because many tests cannot detect all genetic changes that can cause a particular disorder. Further testing may be required to confirm a negative result.

In some cases, a negative result might not give any useful information. This type of result is called uninformative, indeterminate, inconclusive, or ambiguous. Uninformative test results sometimes occur because everyone has common, natural variations in their DNA, called polymorphisms, that do not affect health. Polymorphism in biology occurs when two or more clearly different Phenotypes exist in the same population of a species — in other words the occurrence of more than one If a genetic test finds a change in DNA that has not been associated with a disorder in other people, it can be difficult to tell whether it is a natural polymorphism or a disease-causing mutation. An uninformative result cannot confirm or rule out a specific diagnosis, and it cannot indicate whether a person has an increased risk of developing a disorder. In some cases, testing other affected and unaffected family members can help clarify this type of result.

Cost and time

The cost of genetic testing can range from under $100(£50) to more than $2,000(£1000), depending on the nature and complexity of the test. The cost increases if more than one test is necessary or if multiple family members must be tested to obtain a meaningful result. In countries with private health insurance, in many cases, health insurance plans will cover the costs of genetic testing when it is recommended by a person's doctor.

From the date that a sample is taken, it may take a few weeks to several months to receive the test results. Results for prenatal testing are usually available more quickly because time is an important consideration in making decisions about a pregnancy.

Genetic testing has potential benefits whether the results are positive or negative for a gene mutation. Test results can provide a sense of relief from uncertainty and help people make informed decisions about managing their health care. For example, a negative result can eliminate the need for unnecessary checkups and screening tests in some cases. A positive result can direct a person toward available prevention, monitoring, and treatment options. Some test results can also help people make decisions about having children. Newborn screening can identify genetic disorders early in life so treatment can be started as early as possible.

Risks and limitations

The physical risks associated with most genetic tests are very small, particularly for those tests that require only a blood sample or buccal smear (a procedure that samples cells from the inside surface of the cheek). The procedures used for prenatal testing carry a small but real risk of losing the pregnancy (miscarriage) because they require a sample of amniotic fluid or tissue from around the fetus.

Many of the risks associated with genetic testing involve the emotional, social, or financial consequences of the test results. People may feel angry, depressed, anxious, or guilty about their results. In some cases, genetic testing creates tension within a family because the results can reveal information about other family members in addition to the person who is tested. The possibility of genetic discrimination in employment or insurance is also a concern. Genetic discrimination occurs when people are treated differently by their Employer or Insurance company because they have a Gene Mutation that Some individuals avoid genetic testing out of fear it will impede their ability to purchase insurance or find a job. [1] Health insurers do not currently require applicants for coverage to undergo genetic testing, and when insurers encounter genetic information, it is subject to the same confidentiality protections as any other sensitive health information. [2] Legislation in the United States called the Genetic Information Nondiscrimination Act prohibits group health plans and health insurers from denying coverage to a healthy individual or charging that person higher premiums based solely on a genetic predisposition to developing a disease in the future. The United States of America —commonly referred to as the The Genetic Information Nondiscrimination Act ( GINA) is a law in the United States designed to prohibit the improper use of Genetic information in A genetic predisposition is a genetic effect which influences the Phenotype of an organism but which can be modified by the environmental conditions The legislation also bars employers from using individuals’ genetic information when making hiring, firing, job placement, or promotion decisions. Firing refers to a decision made by an Employer to terminate employment. [3] It was signed into law by the President on May 21, 2008. Events 878 - Syracuse Italy is captured by the Muslim sultan of Sicily. 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common [4][5]

Genetic testing can provide only limited information about an inherited condition. The test often can't determine if a person will show symptoms of a disorder, how severe the symptoms will be, or whether the disorder will progress over time. Another major limitation is the lack of treatment strategies for many genetic disorders once they are diagnosed.

A genetics professional can explain in detail the benefits, risks, and limitations of a particular test. It is important that any person who is considering genetic testing understand and weigh these factors before making a decision.

Many people are also concerned about the privacy implications of genetic testimony. In the United States, federal law requires that this kind of medical information to be kept confidential. The United States of America —commonly referred to as the

Direct-to-Consumer (DTC) Genetic Testing

Direct-to-Consumer (DTC) genetic testing is a type of genetic test that is accessible directly to the consumer without having to go through a health care professional. Usually, to attain a genetic test, health care professionals such as doctors acquire the permission of the patient and order the desired test. DTC genetic tests, however, allow consumers to bypass this process and order one themselves. There are a variety of DTC tests, ranging from testing for breast cancer alleles to mutations linked to cystic fibrosis. Benefits of DTC testing are the accessibility of tests to consumers, promotion of proactive healthcare and the privacy of genetic information. Possible additional risks of DTC testing are the lack of governmental regulation and the potential misinterpretation of genetic information.

Controversy

DTC genetic testing has been controversial due to outspoken opposition within the scientific community. Critics of DTC testing argue against the risks involved, the unregulated advertising and marketing claims, and the overall lack of governmental oversight. [6]

DTC testing involves many of the same risks associated with any genetic test. One of the more obvious and dangerous of these is the possibility of severe misreading of test results. Without professional guidance, consumers can potentially misinterpret genetic information, causing them to be deluded about their personal health.

Some advertising for direct-to-consumer genetic testing has been criticized as conveying an exaggerated and inaccurate message about the connection between genetic information and disease risk, utilizing emotions as a selling factor. An advertisement for a BRCA-predictive genetic test for breast cancer stated: “There is no stronger antidote for fear than information. ”[7]

Government Regulation

Currently, there is no strong federal regulation moderating the DTC market. Though there are several hundred tests available, only a handful are approved by the FDA, which are sold as at-home test kits. Due to the nature of the majority of DTC tests as mailed in DNA samples, it is difficult for the FDA to exercise a form of jurisdiction as the tests are completed in the laboratories of providers, and are not in fact sold as medical devices. Additionally, the FDA has not yet officially substantiated with scientific evidence the claimed accuracy of the majority of direct-to-consumer genetic tests. [8]

On April 24, 2008, the United States Senate passed the Genetic Information Nondiscrimination Act with a vote of 95-0. The United States Senate is the Upper house of the bicameral United States Congress, the Lower house being the House of Representatives The Genetic Information Nondiscrimination Act ( GINA) is a law in the United States designed to prohibit the improper use of Genetic information in The act is the first of its kind in the U. S. to prevent discrimination against people based on their genetic information. [9] This legislation will bar health insurance companies and employers from discriminating against individuals who may be genetically susceptible to devastating illnesses or diseases.

Fiction

Some possible future ethical problems of genetic testing were considered in the science fiction film Gattaca, and the science fiction anime series "Gundam Seed". Science fiction Film is a Film genre that uses speculative, Science -based depictions of imaginary phenomena such as extra-terrestrial Gattaca is a 1997 science fiction Drama film written and directed by Andrew Niccol, starring Ethan Hawke, Uma (anime in Japanese, shortened to Gundam SEED, is an Anime television series and a Manga series by Sunrise.

References

  1. ^ Amy Harmon, "Insurance Fears Lead Many to Shun DNA Tests," The New York Times, February 24, 2008
  2. ^ "Genetic Information and Medical Expense Insurance", American Academy of Actuaries, June 2000
  3. ^ Statement of Administration policy, Executive Office of the President, Office of Management and Budget, 27 April 2007
  4. ^ Keim, Brandon. The The American Academy of Actuaries, also known as the “ Academy ” or the AAA, is the body that represents and unites United States actuaries Events 1124 - David I becomes King of Scotland. 1296 - Battle of Dunbar: The Scots are defeated Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. "Genetic Discrimination by Insurers, Employers Becomes a Crime", Wired. com, May 21, 2008. Events 878 - Syracuse Italy is captured by the Muslim sultan of Sicily. 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common Retrieved on 2008-05-28. 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common Events 585 BC - A Solar eclipse occurs as predicted by Greek philosopher and scientist Thales, while Alyattes is battling  
  5. ^ "Administration News | President Bush Signs Genetic Nondiscrimination Legislation Into Law," Kaiser Daily Health Policy Report, Kaiser Family Foundation, May 22, 2008
  6. ^ Hunter et al. The Henry J Kaiser Family Foundation (KFF, or just Kaiser Family Foundation, is a U , "Letting the Genome out of the Bottle" New England Journal of Medicine
  7. ^ Gollust et al. , "Limitations of Direct-to-Consumer Advertising for Clinical Genetic Testing," JAMA. 2002; 288: 1762-1767
  8. ^ Shawna Williams and Gail Javitt, "Direct-to-consumer genetic testing: empowering or endangering the public?," The Genetics and Public Policy Center, July 25, 2006 (updated 6/15/2007)
  9. ^ [1]

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