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Genetic testing, also known as DNA testing, is used to identify changes in DNA sequence or
chromosome A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins are ...
structure. Genetic testing can also include measuring the results of genetic changes, such as
RNA Ribonucleic acid (RNA) is a polymeric molecule essential in various biological roles in coding, decoding, regulation and expression of genes. RNA and deoxyribonucleic acid ( DNA) are nucleic acids. Along with lipids, proteins, and carbohydra ...
analysis as an output of
gene expression Gene expression is the process by which information from a gene is used in the synthesis of a functional gene product that enables it to produce end products, protein or non-coding RNA, and ultimately affect a phenotype, as the final effect. The ...
, or through
biochemical analysis Biochemistry or biological chemistry is the study of chemical processes within and relating to living organisms. A sub-discipline of both chemistry and biology, biochemistry may be divided into three fields: structural biology, enzymology an ...
to measure specific
protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...
output. In a medical setting, genetic testing can be used to diagnose or rule out suspected
genetic disorders A genetic disorder is a health problem caused by one or more abnormalities in the genome. It can be caused by a mutation in a single gene (monogenic) or multiple genes (polygenic) or by a chromosomal abnormality. Although polygenic disorders ...
, predict risks for specific conditions, or gain information that can be used to customize medical treatments based on an individual's genetic makeup. Genetic testing can also be used to determine biological relatives, such as a child's
biological parentage A parent is a caregiver of the offspring in their own species. In humans, a parent is the caretaker of a child (where "child" refers to offspring, not necessarily age). A ''biological parent'' is a person whose gamete resulted in a child, a mal ...
(genetic mother and father) through
DNA paternity testing DNA paternity testing is the use of DNA profiles to determine whether an individual is the biological parent of another individual. Paternity testing can be especially important when the rights and duties of the father are in issue and a child ...
, or be used to broadly predict an individual's
ancestry An ancestor, also known as a forefather, fore-elder or a forebear, is a parent or (recursively) the parent of an antecedent (i.e., a grandparent, great-grandparent, great-great-grandparent and so forth). ''Ancestor'' is "any person from whom ...
. Genetic testing of plants and animals can be used for similar reasons as in humans (e.g. to assess relatedness/ancestry or predict/diagnose genetic disorders), to gain information used for
selective breeding Selective breeding (also called artificial selection) is the process by which humans use animal breeding and plant breeding to selectively develop particular phenotypic traits (characteristics) by choosing which typically animal or plant mal ...
, or for efforts to boost
genetic diversity Genetic diversity is the total number of genetic characteristics in the genetic makeup of a species, it ranges widely from the number of species to differences within species and can be attributed to the span of survival for a species. It is dis ...
in endangered populations. The variety of genetic tests has expanded throughout the years. Early forms of genetic testing which began in the 1950s involved counting the number of chromosomes per cell. Deviations from the expected number of chromosomes (46 in humans) could lead to a diagnosis of certain genetic conditions such as trisomy 21 (
Down syndrome Down syndrome or Down's syndrome, also known as trisomy 21, is a genetic disorder caused by the presence of all or part of a third copy of chromosome 21. It is usually associated with physical growth delays, mild to moderate intellectual dis ...
) or monosomy X (
Turner syndrome Turner syndrome (TS), also known as 45,X, or 45,X0, is a genetic condition in which a female is partially or completely missing an X chromosome. Signs and symptoms vary among those affected. Often, a short and webbed neck, low-set ears, low hair ...
). In the 1970s, a method to stain specific regions of chromosomes, called chromosome banding, was developed that allowed more detailed
analysis Analysis ( : analyses) is the process of breaking a complex topic or substance into smaller parts in order to gain a better understanding of it. The technique has been applied in the study of mathematics and logic since before Aristotle (38 ...
of chromosome structure and diagnosis of genetic disorders that involved large structural rearrangements. In addition to analyzing whole chromosomes (
cytogenetics Cytogenetics is essentially a branch of genetics, but is also a part of cell biology/cytology (a subdivision of human anatomy), that is concerned with how the chromosomes relate to cell behaviour, particularly to their behaviour during mitosis an ...
), genetic testing has expanded to include the fields of
molecular genetics Molecular genetics is a sub-field of biology that addresses how differences in the structures or expression of DNA molecules manifests as variation among organisms. Molecular genetics often applies an "investigative approach" to determine the ...
and
genomics Genomics is an interdisciplinary field of biology focusing on the structure, function, evolution, mapping, and editing of genomes. A genome is an organism's complete set of DNA, including all of its genes as well as its hierarchical, three-dim ...
which can identify changes at the level of individual genes, parts of genes, or even single
nucleotide Nucleotides are organic molecules consisting of a nucleoside and a phosphate. They serve as monomeric units of the nucleic acid polymers – deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), both of which are essential biomolecules wi ...
"letters" of DNA sequence. According to the
National Institutes of Health The National Institutes of Health, commonly referred to as NIH (with each letter pronounced individually), is the primary agency of the United States government responsible for biomedical and public health research. It was founded in the late ...
, there are tests available for more than 2,000 genetic conditions, and one study estimated that as of 2018 there were more than 68,000 genetic tests on the market.


Types

Genetic testing is "the analysis of
chromosome A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins are ...
s ( DNA), proteins, and certain
metabolite In biochemistry, a metabolite is an intermediate or end product of metabolism. The term is usually used for small molecules. Metabolites have various functions, including fuel, structure, signaling, stimulatory and inhibitory effects on enzymes, c ...
s in order to detect heritable disease-related
genotype The genotype of an organism is its complete set of genetic material. Genotype can also be used to refer to the alleles or variants an individual carries in a particular gene or genetic location. The number of alleles an individual can have in a ...
s,
mutation In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA or viral replication, mi ...
s,
phenotype In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology or physical form and structure, its developmental processes, its biochemical and physiological proper ...
s, or
karyotype A karyotype is the general appearance of the complete set of metaphase chromosomes in the cells of a species or in an individual organism, mainly including their sizes, numbers, and shapes. Karyotyping is the process by which a karyotype is disce ...
s for clinical purposes." It can provide information about a
person A person ( : people) is a being that has certain capacities or attributes such as reason, morality, consciousness or self-consciousness, and being a part of a culturally established form of social relations such as kinship, ownership of property, ...
's genes and chromosomes throughout life.


Diagnostic testing

*
Cell-free fetal DNA Cell-free fetal DNA (cffDNA) is fetal DNA that circulates freely in the maternal blood. Maternal blood is sampled by venipuncture. Analysis of cffDNA is a method of non-invasive prenatal diagnosis frequently ordered for pregnant women of advanced ...
(cffDNA) testing - a non-invasive (for the fetus) test. It is performed on a sample of venous blood from the mother, and can provide information about the fetus early in pregnancy. it is the most sensitive and specific screening test for
Down syndrome Down syndrome or Down's syndrome, also known as trisomy 21, is a genetic disorder caused by the presence of all or part of a third copy of chromosome 21. It is usually associated with physical growth delays, mild to moderate intellectual dis ...
. *
Newborn screening Newborn screening (NBS) is a public health program of screening in infants shortly after birth for conditions that are treatable, but not clinically evident in the newborn period. The goal is to identify infants at risk for these conditions earl ...
- used just after birth to identify genetic disorders that can be treated early in life. A blood sample is collected with a heel prick from the newborn 24–48 hours after birth and sent to the lab for analysis. In the United States, newborn screening procedure varies state by state, but all states by law test for at least 21 disorders. If abnormal results are obtained, it does not necessarily mean the child has the disorder. Diagnostic tests must follow the initial screening to confirm the disease. The routine testing of infants for certain disorders is the most widespread use of genetic testing—millions of babies are tested each year in the United States. All states currently test infants for
phenylketonuria Phenylketonuria (PKU) is an inborn error of metabolism that results in decreased metabolism of the amino acid phenylalanine. Untreated PKU can lead to intellectual disability, seizures, behavioral problems, and mental disorders. It may also resu ...
(a genetic disorder that causes
mental illness A mental disorder, also referred to as a mental illness or psychiatric disorder, is a behavioral or mental pattern that causes significant distress or impairment of personal functioning. Such features may be persistent, relapsing and remitti ...
if left untreated) and
congenital A birth defect, also known as a congenital disorder, is an abnormal condition that is present at birth regardless of its cause. Birth defects may result in disabilities that may be physical, intellectual, or developmental. The disabilities can ...
hypothyroidism Hypothyroidism (also called ''underactive thyroid'', ''low thyroid'' or ''hypothyreosis'') is a disorder of the endocrine system in which the thyroid gland does not produce enough thyroid hormone. It can cause a number of symptoms, such as po ...
(a disorder of the
thyroid The thyroid, or thyroid gland, is an endocrine gland in vertebrates. In humans it is in the neck and consists of two connected lobes. The lower two thirds of the lobes are connected by a thin band of tissue called the thyroid isthmus. The thy ...
gland). People with PKU do not have an enzyme needed to process the amino acid phenylalanine, which is responsible for normal growth in children and normal protein use throughout their lifetime. If there is a buildup of too much phenylalanine, brain tissue can be damaged, causing developmental delay. Newborn screening can detect the presence of PKU, allowing children to be placed on special diets to avoid the effects of the disorder. *
Diagnostic testing A medical test is a medical procedure performed to detect, diagnose, or monitor diseases, disease processes, susceptibility, or to determine a course of treatment. Medical tests such as, physical and visual exams, diagnostic imaging, genetic te ...
- used to diagnose 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 mutations and symptoms. Diagnostic testing can be performed 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 disease. For example, people with a family history of polycystic kidney disease (PKD) who experience pain or tenderness in their abdomen, blood in their urine, frequent urination, pain in the sides, a urinary tract infection or kidney stones may decide to have their genes tested and the result could confirm the diagnosis of PKD. Despite the several implications of genetic testing in conditions such as epilepsy or neurodevelopmental disorders, many patients (specially adults) do not have access to these modern diagnostic approaches, showing a relevant diagnostic gap *
Carrier testing Carrier testing is a type of genetic testing that is used to determine if a person is a carrier for specific Dominance (genetics), autosomal recessive diseases. This kind of testing is used most often by couples who are considering becoming pregna ...
- used 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 ethnic groups with an increased risk of specific genetic conditions. If both parents are tested, the test can provide information about a couple's risk of having a child with a genetic condition like
cystic fibrosis Cystic fibrosis (CF) is a rare genetic disorder that affects mostly the lungs, but also the pancreas, liver, kidneys, and intestine. Long-term issues include difficulty breathing and coughing up mucus as a result of frequent lung infections. O ...
. *
Preimplantation genetic diagnosis Preimplantation genetic diagnosis (PGD or PIGD) is the genetic profiling of embryos prior to implantation (as a form of embryo profiling), and sometimes even of oocytes prior to fertilization. PGD is considered in a similar fashion to prenatal ...
- performed on
human embryo Human embryonic development, or human embryogenesis, is the development and formation of the human embryo. It is characterised by the processes of cell division and cellular differentiation of the embryo that occurs during the early stages of de ...
s prior to the implantation as part of an
in vitro fertilization In vitro fertilisation (IVF) is a process of fertilisation where an egg is combined with sperm in vitro ("in glass"). The process involves monitoring and stimulating an individual's ovulatory process, removing an ovum or ova (egg or eggs) ...
procedure. Pre-implantation testing is used when individuals try to conceive a child through in vitro fertilization. Eggs from the woman and sperm from the man are removed and fertilized outside the body to create multiple embryos. The embryos are individually screened for abnormalities, and the ones without abnormalities are implanted in the uterus. *
Prenatal diagnosis Prenatal testing consists of prenatal screening and prenatal diagnosis, which are aspects of prenatal care that focus on detecting problems with the pregnancy as early as possible. These may be anatomic and physiologic problems with the health of ...
- used to detect changes in a
fetus A fetus or foetus (; plural fetuses, feti, foetuses, or foeti) is the unborn offspring that develops from an animal embryo. Following embryonic development the fetal stage of development takes place. In human prenatal development, fetal deve ...
's genes or chromosomes before birth. This type of testing is offered to couples with an increased risk of having a baby with a genetic or chromosomal disorder. In some cases, prenatal testing can lessen a couple's uncertainty or help them decide whether to abort the pregnancy. It cannot identify all possible inherited disorders and
birth defect A birth defect, also known as a congenital disorder, is an abnormal condition that is present at birth regardless of its cause. Birth defects may result in disabilities that may be physical, intellectual, or developmental. The disabilities can ...
s, however. One method of performing a prenatal genetic test involves an amniocentesis, which removes a sample of fluid from the mother's amniotic sac 15 to 20 or more weeks into pregnancy. The fluid is then tested for chromosomal abnormalities such as Down syndrome (Trisomy 21) and Trisomy 18, which can result in neonatal or fetal death. Test results can be retrieved within 7–14 days after the test is done. This method is 99.4% accurate at detecting and diagnosing fetal chromosome abnormalities. There is a slight risk of miscarriage with this test, about 1:400. Another method of prenatal testing is Chorionic Villus Sampling (CVS). Chorionic villi are projections from the placenta that carry the same genetic makeup as the baby. During this method of prenatal testing, a sample of chorionic villi is removed from the placenta to be tested. This test is performed 10–13 weeks into pregnancy and results are ready 7–14 days after the test was done. Another test using blood taken from the fetal umbilical cord is
percutaneous umbilical cord blood sampling Percutaneous umbilical cord blood sampling (PUBS), also called cordocentesis, fetal blood sampling, or umbilical vein sampling is a diagnostic genetic test that examines blood from the fetal umbilical cord to detect fetal abnormalities. Fetal and ...
. * Predictive and presymptomatic testing - used to detect gene mutations associated with disorders that appear after birth, often later in life. These tests can be helpful to people who have a family member with a genetic disorder, but who have no features of the disorder themselves at the time of testing. Predictive testing can identify mutations that increase a person's chances of developing disorders with a genetic basis, such as certain types of
cancer Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal b ...
. For example, an individual with a mutation in ''
BRCA1 Breast cancer type 1 susceptibility protein is a protein that in humans is encoded by the ''BRCA1'' () gene. Orthologs are common in other vertebrate species, whereas invertebrate genomes may encode a more distantly related gene. ''BRCA1'' is a h ...
'' has a 65% cumulative risk of
breast cancer Breast cancer is cancer that develops from breast tissue. Signs of breast cancer may include a lump in the breast, a change in breast shape, dimpling of the skin, milk rejection, fluid coming from the nipple, a newly inverted nipple, or a re ...
. Hereditary breast cancer along with ovarian cancer syndrome are caused by gene alterations in the genes BRCA1 and BRCA2. Major cancer types related to mutations in these genes are female breast cancer, ovarian, prostate, pancreatic, and male breast cancer. Li-Fraumeni syndrome is caused by a gene alteration on the gene TP53. Cancer types associated with a mutation on this gene include breast cancer, soft tissue sarcoma, osteosarcoma (bone cancer), leukemia and brain tumors. In the Cowden syndrome there is a mutation on the PTEN gene, causing potential breast, thyroid or endometrial cancer. Presymptomatic testing can determine whether a person will develop a genetic disorder, such as
hemochromatosis Iron overload or hemochromatosis (also spelled ''haemochromatosis'' in British English) indicates increased total accumulation of iron in the body from any cause and resulting organ damage. The most important causes are hereditary haemochromatosi ...
(an iron overload disorder), before any signs or symptoms appear. The results of predictive and presymptomatic testing can provide information about a person's risk of developing a specific disorder, help with making decisions about medical care and provide a better prognosis. *
Pharmacogenomics Pharmacogenomics is the study of the role of the genome in drug response. Its name ('' pharmaco-'' + ''genomics'') reflects its combining of pharmacology and genomics. Pharmacogenomics analyzes how the genetic makeup of an individual affects the ...
- determines the influence of genetic variation on drug response. When a person has a disease or health condition, pharmacogenomics can examine an individual's genetic makeup to determine what medicine and what dosage would be the safest and most beneficial to the patient. In the human population, there are approximately 11 million single nucleotide polymorphisms (SNPs) in people's genomes, making them the most common variations in the human genome. SNPs reveal information about an individual's response to certain drugs. This type of genetic testing can be used for cancer patients undergoing chemotherapy. A sample of the cancer tissue can be sent in for genetic analysis by a specialized lab. After analysis, information retrieved can identify mutations in the tumor which can be used to determine the best treatment option.


Non-diagnostic testing

*
Forensic testing Forensic identification is the application of forensic science, or "forensics", and technology to identify specific objects from the trace evidence they leave, often at a crime scene or the scene of an accident. Forensic means "for the courts". Hu ...
- 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). *
Paternity testing DNA paternity testing is the use of DNA profiles to determine whether an individual is the biological parent of another individual. Paternity testing can be especially important when the rights and duties of the father are in issue and a child ...
- uses special DNA markers to identify the same or similar inheritance patterns between related individuals. Based on the fact that we all inherit half of our DNA from the father, and half from the mother, DNA scientists test individuals to find the match of DNA sequences at some highly differential markers to draw the conclusion of relatedness. *
Genealogical DNA test A genealogical DNA test is a DNA-based test used in genetic genealogy that looks at specific locations of a person's genome in order to find or verify ancestral genealogical relationships, or (with lower reliability) to estimate the ethnic mixt ...
- used to determine ancestry or ethnic heritage for
genetic genealogy Genetic genealogy is the use of genealogical DNA tests, i.e., DNA profiling and DNA testing, in combination with traditional genealogical methods, to infer genetic relationships between individuals. This application of genetics came to be used b ...
. * Research testing - includes finding unknown genes, learning how genes work and advancing understanding of genetic conditions. The results of testing done as part of a research study are usually not available to patients or their healthcare providers.


Medical procedure

Genetic testing is often done as part of a genetic consultation and as of mid-2008 there were more than 1,200 clinically applicable genetic tests available. 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 principle in medical ethics and medical law, that a patient must have sufficient information and understanding before making decisions about their medical care. Pertinent information may include risks and benefits of treatme ...
. Genetic tests are performed on a sample of
blood Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood in the c ...
,
hair Hair is a protein filament that grows from follicles found in the dermis. Hair is one of the defining characteristics of mammals. The human body, apart from areas of glabrous skin, is covered in follicles which produce thick terminal and f ...
,
skin Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation. Other cuticle, animal coverings, such as the arthropod exoskeleton, have diffe ...
,
amniotic fluid The amniotic fluid is the protective liquid contained by the amniotic sac of a gravid amniote. This fluid serves as a cushion for the growing fetus, but also serves to facilitate the exchange of nutrients, water, and biochemical products betwee ...
(the fluid that surrounds a fetus during pregnancy), or other tissue. For example, a
medical procedure A medical procedure is a course of action intended to achieve a result in the delivery of healthcare. A medical procedure with the intention of determining, measuring, or diagnosing a patient condition or parameter is also called a medical test. ...
called a
buccal smear A buccal swab, also known as buccal smear, is a way to collect DNA from the cells on the inside of a person's cheek. Buccal swabs are a relatively non-invasive way to collect DNA samples for testing. Buccal means ''cheek'' or ''mouth''. It is ve ...
uses a small brush or cotton swab to collect a sample of cells from the inside surface of the cheek. Alternatively, a small amount of saline
mouthwash Mouthwash, mouth rinse, oral rinse, or mouth bath is a liquid which is held in the mouth passively or swilled around the mouth by contraction of the perioral muscles and/or movement of the head, and may be gargling, gargled, where the head is ti ...
may be swished in the mouth to collect the cells. The sample is sent to a laboratory where technicians look for specific changes in chromosomes, DNA, or proteins, depending on the suspected disorders, often using
DNA sequencing DNA sequencing is the process of determining the nucleic acid sequence – the order of nucleotides in DNA. It includes any method or technology that is used to determine the order of the four bases: adenine, guanine, cytosine, and thymine. Th ...
. The laboratory reports the test results in writing to a person's doctor or genetic counselor. Routine
newborn An infant or baby is the very young offspring of human beings. ''Infant'' (from the Latin word ''infans'', meaning 'unable to speak' or 'speechless') is a formal or specialised synonym for the common term ''baby''. The terms may also be used to ...
screening tests are done on a small blood sample obtained by pricking the baby's heel with a lancet.


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 non-negligible 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. The potential negative impact of genetic testing has led to an increasing recognition of a "right not to know". 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 Genetic discrimination occurs when people treat others (or are treated) differently because they have or are perceived to have a gene mutation(s) that causes or increases the risk of an inherited disorder. It may also refer to any and all discri ...
in employment or insurance is also a concern. Some individuals avoid genetic testing out of fear it will affect their ability to purchase insurance or find a job. 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. In the United States, the use of genetic information is governed by the
Genetic Information Nondiscrimination Act The Genetic Information Nondiscrimination Act of 2008 (, GINA ), is an Act of Congress in the United States designed to prohibit some types of genetic discrimination. The act bars the use of genetic information in health insurance and employ ...
(GINA) (see discussion below in the section on government regulation). 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. Another limitation to genetic testing for a hereditary linked cancer, is the variants of unknown clinical significance. Because the human genome has over 22,000 genes, there are 3.5 million variants in the average person's genome. These variants of unknown clinical significance means there is a change in the DNA sequence, however the increase for cancer is unclear because it is unknown if the change affects the gene's function. 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. Other risks include
incidental findings Incidental medical findings are previously undiagnosed medical or psychiatric conditions that are discovered unintentionally and during evaluation for a medical or psychiatric condition. Such findings may occur in a variety of settings, including ro ...
—a discovery of some possible problem found while looking for something else. In 2013 the American College of Medical Genetics and Genomics (ACMG) that certain genes always be included any time a genomic sequencing was done, and that labs should report the results. DNA studies have been criticised for a range of methodological problems and providing misleading, interpretations on racial classifications.


Direct-to-consumer genetic testing

Direct-to-consumer Direct-to-consumer (DTC) or business-to-consumer (B2C) is the business model of selling products directly to customers and thereby bypassing any third-party retailers, wholesalers, or any other middlemen. Direct-to-consumer sales are usually tr ...
(DTC) genetic testing (also called at-home 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 obtain a genetic test, health care professionals such as physicians, nurse practitioners, or
genetic counselors Genetic counseling is the process of investigating individuals and families affected by or at risk of genetic disorders to help them understand and adapt to the medical, psychological and familial implications of genetic contributions to disease; t ...
acquire their patient's permission and then order the desired test, which may or may not be covered by health insurance. DTC genetic tests, however, allow consumers to bypass this process and purchase DNA tests themselves. DTC genetic testing can entail primarily genealogical/ancestry-related information, health and trait-related information, or both. There is a variety of DTC tests, ranging from tests for breast cancer alleles to mutations linked to
cystic fibrosis Cystic fibrosis (CF) is a rare genetic disorder that affects mostly the lungs, but also the pancreas, liver, kidneys, and intestine. Long-term issues include difficulty breathing and coughing up mucus as a result of frequent lung infections. O ...
. Possible 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, the potential misinterpretation of genetic information, issues related to testing minors, privacy of data, and downstream expenses for the public health care system. In the United States, most DTC genetic test kits are not reviewed by the Food and Drug Administration (FDA), with the exception of a few tests offered by the company
23andMe 23andMe Holding Co. is a publicly held personal genomics and biotechnology company based in South San Francisco, California. It is best known for providing a direct-to-consumer genetic testing service in which customers provide a saliva sample t ...
. As of 2019, the tests that have received marketing authorization by the FDA include 23andMe's genetic health risk reports for select variants of BRCA1/BRCA2, pharmacogenetic reports that test for selected variants associated with metabolism of certain pharmaceutical compounds, a carrier screening test for
Bloom syndrome Bloom syndrome (often abbreviated as BS in literature) is a rare autosomal recessive genetic disorder characterized by short stature, predisposition to the development of cancer, and genomic instability. BS is caused by mutations in the ''BLM'' gen ...
, and genetic health risk reports for a handful of other medical conditions, such as
celiac disease Coeliac disease (British English) or celiac disease (American English) is a long-term autoimmune disorder, primarily affecting the small intestine, where individuals develop intolerance to gluten, present in foods such as wheat, rye and barl ...
and late-onset Alzheimer's.


Controversy

DTC genetic testing has been controversial due to outspoken opposition within the medical community. Critics of DTC testing argue against the risks involved, the unregulated advertising and
marketing claim Advertising slogans are short phrases used in advertising campaigns to generate publicity and unify a company's marketing strategy. The phrases may be used to attract attention to a distinctive product feature or reinforce a company's brand. Etym ...
s, the potential reselling of genetic data to third parties, and the overall lack of governmental oversight. 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 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 DTC 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.” Apart from rare diseases that are directly caused by specific, single-gene mutation, diseases "have complicated, multiple genetic links that interact strongly with personal environment, lifestyle, and behavior."
Ancestry.com Ancestry.com LLC is an American genealogy company based in Lehi, Utah. The largest for-profit genealogy company in the world, it operates a network of genealogical, historical records, and related genetic genealogy websites. In November 2018, ...
, a company providing DTC DNA tests for
genealogy Genealogy () is the study of families, family history, and the tracing of their lineages. Genealogists use oral interviews, historical records, genetic analysis, and other records to obtain information about a family and to demonstrate kins ...
purposes, has reportedly allowed the
warrantless search A search warrant is a court order that a magistrate or judge issues to authorize law enforcement officers to conduct a search of a person, location, or vehicle for evidence of a crime and to confiscate any evidence they find. In most countries, ...
of their database by police investigating a murder. The warrantless search led to a search warrant to force the gathering of a DNA sample from a New Orleans filmmaker; however he turned out not to be a match for the suspected killer.


Governmental genetic testing


In Estonia

As part of its healthcare system, Estonia is offering all of its residents genome-wide genotyping. This will be translated into personalized reports for use in everyday medical practice via the national e-health portal. The aim is to minimise health problems by warning participants most at risk of conditions such as cardiovascular disease and diabetes. It is also hoped that participants who are given early warnings will adopt healthier lifestyles or take preventative drugs.


Private genetic testing

Genetic testing has also been taken on by private companies, such as
23andMe 23andMe Holding Co. is a publicly held personal genomics and biotechnology company based in South San Francisco, California. It is best known for providing a direct-to-consumer genetic testing service in which customers provide a saliva sample t ...
,
Ancestry.com Ancestry.com LLC is an American genealogy company based in Lehi, Utah. The largest for-profit genealogy company in the world, it operates a network of genealogical, historical records, and related genetic genealogy websites. In November 2018, ...
, and
Family Tree DNA FamilyTreeDNA is a division of Gene by Gene, a commercial genetic testing company based in Houston, Texas. FamilyTreeDNA offers analysis of autosomal DNA, YDNA, Y-DNA, and mitochondrial DNA to individuals for genealogical purpose. With a database ...
. These companies will send the consumer a kit at their home address, with which they will provide a saliva sample for their lab to analyze. The company will then send back the consumer’s results in a few weeks, which is a breakdown of their ancestral heritage and possible health risks that accompany it. Other companies, like
National Geographic ''National Geographic'' (formerly the ''National Geographic Magazine'', sometimes branded as NAT GEO) is a popular American monthly magazine published by National Geographic Partners. Known for its photojournalism, it is one of the most widely ...
, have conducted public DNA surveys in an effort to better understand global ancestry and heritage. In 2005, National Geographic launched the
Genographic Project The Genographic Project, launched on 13 April 2005 by the National Geographic Society and IBM, was a genetic anthropological study (sales discontinued on 31 May 2019) that aimed to map historical human migrations patterns by collecting and ...
, which was a fifteen year project that was discontinued in 2020. Over one million people participated in the DNA sampling from more than 140 countries, which made the project the largest of its kind ever conducted. The project asked for DNA samples from indigenous people as well as the general public, which spurred political controversy among some indigenous groups, leading to the coining of the term "biocolonialism".


Government regulation


In the United States

With regard to genetic testing and information in general, legislation in the United States called the
Genetic Information Nondiscrimination Act The Genetic Information Nondiscrimination Act of 2008 (, GINA ), is an Act of Congress in the United States designed to prohibit some types of genetic discrimination. The act bars the use of genetic information in health insurance and employ ...
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 A genetic predisposition is a genetic characteristic which influences the possible phenotypic development of an individual organism within a species or population under the influence of environmental conditions. In medicine, genetic susceptibilit ...
to developing a disease in the future. The legislation also bars employers from using individuals’ genetic information when making hiring,
firing Dismissal (also called firing) is the termination of employment by an employer against the will of the employee. Though such a decision can be made by an employer for a variety of reasons, ranging from an economic downturn to performance-related ...
, job placement, or
promotion Promotion may refer to: Marketing * Promotion (marketing), one of the four marketing mix elements, comprising any type of marketing communication used to inform or persuade target audiences of the relative merits of a product, service, brand or i ...
decisions.Statement of Administration policy
Executive Office of the President, Office of Management and Budget, 27 April 2007
Although GINA protects against genetic discrimination, Section 210 of the law states that once the disease has manifested, employers can use the medical information and not be in violation of the law, even if the condition has a genetic basis. The legislation, the first of its kind in the United States,Kennedy in support of genetic information nondiscrimination bill
Abril 24, 2008. Last access: 28/05/2008.
was passed by the
United States Senate The United States Senate is the upper chamber of the United States Congress, with the House of Representatives being the lower chamber. Together they compose the national bicameral legislature of the United States. The composition and pow ...
on April 24, 2008, on a vote of 95–0, and was signed into law by President
George W. Bush George Walker Bush (born July 6, 1946) is an American politician who served as the 43rd president of the United States from 2001 to 2009. A member of the Republican Party, Bush family, and son of the 41st president George H. W. Bush, he ...
on May 21, 2008. It went into effect on November 21, 2009. In June 2013 the US Supreme Court issued two rulings on human genetics. The Court struck down patents on human genes, opening up competition in the field of genetic testing. The Supreme Court also ruled that police were allowed to collect DNA from people arrested for serious offenses.


In the European Union

Effective as of 25 May 2018, companies that process genetic data must abide by the
General Data Protection Regulation The General Data Protection Regulation (GDPR) is a European Union regulation on data protection and privacy in the EU and the European Economic Area (EEA). The GDPR is an important component of EU privacy law and of human rights law, in partic ...
(GDPR). The GDPR is a set of rules/regulations that helps an individual take control of their data information that is collected, used and stored digitally or in a structured filing system on paper, and restricts a company's use of personal data. The regulation also applies to companies who offer products/services outside of the EU.


In Russia

Articles 10 and 11 of the Federal Law of July 27, 2006 No. 152-FZ "On Personal Data" provide that the processing of special categories of personal data relating to race, nationality, political views, religious or philosophical beliefs, health status, intimate life is allowed if it is necessary in connection with the implementation of international agreements of the Russian Federation on readmission and is carried out in accordance with the legislation of the Russian Federation on citizenship of the Russian Federation. Information characterizing the physiological and biological characteristics of a person, on the basis of which it is possible to establish his identity (biometric personal data), can be processed without the consent of the subject of personal data in connection with the implementation of international agreements of the Russian Federation on readmission, administration of justice and execution of judicial acts, compulsory state fingerprinting registration, as well as in cases stipulated by the legislation of the Russian Federation on defense, security, anti-terrorism, transport security, anti-corruption, operational investigative activities, public service, as well as in cases stipulated by the criminal-executive legislation of Russia, the legislation of Russia on the procedure for leaving the Russian Federation and entering the Russian Federation, citizenship of the Russian Federation and notaries. In Russia, scientific DNA testing is being actively carried out in order to study the genetic diversity of the peoples of Russia in the framework of the state task - to learn from DNA to determine the probable territory of human origin based on data on the majority of the peoples of the country. On June 16, 2017, the Council of Ministers of the Union State of Belarus and Russia adopted Resolution No. 26, in which it approved the scientific and technical program of the Union State "Development of innovative genogeographic and genomic technologies for identification of personality and individual characteristics of a person based on the study of gene pools of the regions of the Union State" (DNA- identification). Within the framework of this program, it is also planned to include the peoples of neighboring countries, which are the main source of migration, into the genogeographic study on the basis of existing collections.


In popular culture

Some possible future ethical problems of genetic testing were considered in the
science fiction film Science fiction (or sci-fi) is a film genre that uses speculative, fictional science-based depictions of phenomena that are not fully accepted by mainstream science, such as extraterrestrial lifeforms, spacecraft, robots, cyborgs, interstellar ...
''
Gattaca ''Gattaca'' is a 1997 American dystopian science fiction thriller film written and directed by Andrew Niccol in his filmmaking debut. It stars Ethan Hawke and Uma Thurman with Jude Law, Loren Dean, Ernest Borgnine, Gore Vidal, and Alan Arkin ap ...
'', the novel ''Next'', and the science fiction
anime is Traditional animation, hand-drawn and computer animation, computer-generated animation originating from Japan. Outside of Japan and in English, ''anime'' refers specifically to animation produced in Japan. However, in Japan and in Japane ...
series ''
Mobile Suit Gundam Seed is an anime series developed by Sunrise and directed by Mitsuo Fukuda. The ninth installment in the ''Gundam'' franchise, ''Gundam SEED'' takes place in a future calendar era, in this case the Cosmic Era. In this era, mankind has devel ...
''. Also, some films which include the topic of genetic testing include '' The Island'', '' Halloween: The Curse of Michael Myers'', and the ''
Resident Evil ''Resident Evil'', known in Japan as is a Japanese horror game series and media franchise created by Capcom. It consists of survival horror, third-person shooter and first-person shooter games, with players typically surviving in environments ...
'' series.


Children & Religion

Three to five percent of the funding available for the
Human Genome Project The Human Genome Project (HGP) was an international scientific research project with the goal of determining the base pairs that make up human DNA, and of identifying, mapping and sequencing all of the genes of the human genome from both a ...
was set aside to study the many social, ethical, and legal implications that will result from the better understanding of human heredity the rapid expansion of genetic risk assessment by genetic testing which would be facilitated by this project.


Pediatric genetic testing

The
American Academy of Pediatrics The American Academy of Pediatrics (AAP) is an American professional association of pediatricians, headquartered in Itasca, Illinois. It maintains its Department of Federal Affairs office in Washington, D.C. Background The Academy was founded ...
(AAP) and the
American College of Medical Genetics The American College of Medical Genetics and Genomics (ACMG) is an organization composed of biochemical, clinical, cytogenetic, medical and molecular geneticists, genetic counselors and other health care professionals committed to the practice of ...
(ACMG) have provided new guidelines for the ethical issue of
pediatrics Pediatrics ( also spelled ''paediatrics'' or ''pædiatrics'') is the branch of medicine that involves the medical care of infants, children, adolescents, and young adults. In the United Kingdom, paediatrics covers many of their youth until th ...
genetic testing and
screening Screening may refer to: * Screening cultures, a type a medical test that is done to find an infection * Screening (economics), a strategy of combating adverse selection (includes sorting resumes to select employees) * Screening (environmental), a ...
of children in the United States. Their guidelines state that performing pediatric genetic testing should be in the best interest of the child. In hypothetical situations for adults getting genetically tested 84-98% expressing interest in getting genetically tested for cancer predisposition. Though only half who are at risk of would get tested. AAP and ACMG recommend holding off on genetic testing for late-onset conditions until adulthood. Unless diagnosing genetic disorders during childhood and start early intervention can reduce morbidity or mortality. They also state that with parents or guardians permission testing for asymptomatic children who are at risk of childhood onset conditions are ideal reasons for pediatrics genetic testing. Also, with a donor advocate or similar mechanism should be in place to protect the minors from coercion and to safeguard the interest of said minor. Both AAP and ACMG discourage the use of
direct-to-consumer Direct-to-consumer (DTC) or business-to-consumer (B2C) is the business model of selling products directly to customers and thereby bypassing any third-party retailers, wholesalers, or any other middlemen. Direct-to-consumer sales are usually tr ...
and home kit genetic because of the accuracy, interpretation and oversight of test content. Guidelines also state that if parents or guardians should be encouraged to inform their child of the results from the genetic test if the minor is of appropriate age. If minor is of mature appropriate age and request results, the request should be honored. Though for ethical and legal reasons health care providers should be cautions in providing minors with predictive genetic testing without the involvement of parents or guardians. Within the guidelines AAP and ACMG state that
health care provider A health care provider is an individual health professional or a health facility organization licensed to provide health care diagnosis and treatment services including medication, surgery and medical devices. Health care providers often receive ...
have an obligation to inform parents or guardians on the implication of test results. To encourage patients and families to share information and even offer help in explain results to extend family or refer them to genetic counseling. AAP and ACMG state any type of predictive genetic testing for all types is best offer with
genetic counseling Genetic counseling is the process of investigating individuals and families affected by or at risk of genetic disorders to help them understand and adapt to the medical, psychological and familial implications of genetic contributions to disease; t ...
being offer by
Clinical genetics Medical genetics is the branch tics in that human genetics is a field of scientific research that may or may not apply to medicine, while medical genetics refers to the application of genetics to medical care. For example, research on the caus ...
,
genetic counselors Genetic counseling is the process of investigating individuals and families affected by or at risk of genetic disorders to help them understand and adapt to the medical, psychological and familial implications of genetic contributions to disease; t ...
or health care providers.


Israel

In Israel, uses of DNA testing to determine if people are eligible for immigration. The policy where "many Jews from the Former Soviet Union (‘FSU’) are asked to provide DNA confirmation of their Jewish heritage in the form of paternity tests in order to immigrate as Jews and become citizens under Israel's
Law of Return The Law of Return ( he, חֹוק הַשְׁבוּת, ''ḥok ha-shvūt'') is an Israeli law, passed on 5 July 1950, which gives Jews, people with one or more Jewish grandparent, and their spouses the right to relocate to Israel and acquire Isra ...
" has generated controversy.


Costs & Time

The cost of genetic testing can range from under $100 to more than $2,000. This depends on the complexity of the test. The cost will increase if more than one test is necessary or if multiple family members are getting tested to obtain additional results. Costs can vary by state and some states cover part of the total cost. From the date that a sample is taken, results may take weeks to months, depending upon the complexity and extent of the tests being performed. Results for prenatal testing are usually available more quickly because time is an important consideration in making decisions about a pregnancy. Prior to the testing, the doctor or genetic counselor who is requesting a particular test can provide specific information about the cost and time frame associated with that test.


See also

*
Biobank A biobank is a type of biorepository that stores biological samples (usually human) for use in research. Biobanks have become an important resource in medical research, supporting many types of contemporary research like genomics and personalize ...
*
DNA profiling DNA profiling (also called DNA fingerprinting) is the process of determining an individual's DNA characteristics. DNA analysis intended to identify a species, rather than an individual, is called DNA barcoding. DNA profiling is a forensic tec ...
*
Designer baby A designer baby is a baby whose genetics, genetic makeup has been selected or altered, often to not include a particular gene or to remove genes associated with disease. This process usually involves analysing a wide range of human embryos to ide ...
*
Genographic Project The Genographic Project, launched on 13 April 2005 by the National Geographic Society and IBM, was a genetic anthropological study (sales discontinued on 31 May 2019) that aimed to map historical human migrations patterns by collecting and ...
*
Personalized medicine Personalized medicine, also referred to as precision medicine, is a medical model that separates people into different groups—with medical decisions, practices, interventions and/or products being tailored to the individual patient based on the ...
* Pre-implantation genetic diagnosis to avoid birth defects *
Elective genetic and genomic testing Elective may refer to: *Choice, the mental process of judging the merits of multiple options and selecting one of them *Elective course in education ** Elective (medical), a period of study forming part of a medical degree * In medical procedures, ...
*
Eugenics Eugenics ( ; ) is a fringe set of beliefs and practices that aim to improve the genetic quality of a human population. Historically, eugenicists have attempted to alter human gene pools by excluding people and groups judged to be inferior or ...
*
Full Genome Sequencing Whole genome sequencing (WGS), also known as full genome sequencing, complete genome sequencing, or entire genome sequencing, is the process of determining the entirety, or nearly the entirety, of the DNA sequence of an organism's genome at a ...
*
Whole Genome Sequencing Whole genome sequencing (WGS), also known as full genome sequencing, complete genome sequencing, or entire genome sequencing, is the process of determining the entirety, or nearly the entirety, of the DNA sequence of an organism's genome at a s ...
*
Whole Exome Sequencing Exome sequencing, also known as whole exome sequencing (WES), is a genomic technique for sequencing all of the protein-coding regions of genes in a genome (known as the exome). It consists of two steps: the first step is to select only the subset ...
*
Genetic counseling Genetic counseling is the process of investigating individuals and families affected by or at risk of genetic disorders to help them understand and adapt to the medical, psychological and familial implications of genetic contributions to disease; t ...
*
List of genetic disorders The following is a list of genetic disorders and if known, type of mutation and for the chromosome involved. Although the parlance "disease-causing gene" is common, it is the occurrence of an abnormality in the parents that causes the impairment ...
*
List of genetic genealogy topics This is a list of genetic genealogy topics. Important concepts * Genetic genealogy * Genealogical DNA test * Human mitochondrial DNA haplogroups * Human Y-chromosome DNA haplogroups * Allele * Allele frequency * Electropherogram * Genetic reco ...
*
Non-paternity event In genetics, a non-paternity event (also known as misattributed paternity, not parent expected, or NPE) is the situation in which someone who is presumed to be an individual's father is not in fact the biological father. This presumption of NPE is ...
*
New eugenics New eugenics, also known as liberal eugenics (a term coined by bioethicist Nicholas Agar), advocates enhancing human characteristics and capacities through the use of reproductive technology and human genetic engineering. Those who advocate new eu ...


References

{{DEFAULTSORT:Genetic Testing Genetics techniques Medical tests Ethically disputed medical practices Medical genetics Alternatives to animal testing Personalized medicine