Glossary

List of terms with definitions listed in the site glossary
Click one of the letters above to advance the page to terms beginning with that letter.

A

abnormal result
A possible result of a screening test. An abnormal result does not determine a diagnosis, and means additional testing is needed to see if the individual has a condition. Also referred to as positive result.
acquired mutations
A change within a sequence of DNA caused by environment factors (sun, radiation, or chemicals), aging, or chance.
acute

Describes an illness that only affects an individual for a short period of time.

ADA
The Americans with Disabilities Act of 1990 gives civil rights protections to individuals with disabilities and guarantees equal opportunity for individuals with disabilities in public accommodations, employment, transportation, state and local government services, and telecommunications.
adenine

One of four chemical bases in DNA, denoted (A), with the other three being cytosine (C), guanine (G), and thymine (T).

advocacy group

A group of people who work together to support a cause.

alkaptonuria
A rare genetic disorder in which a person's urine turns a dark brownish-black color when exposed to air.
allele

One of two or more versions of a gene. An individual inherits two alleles for each gene, one from each parent.

amino acids

Amino acids are a set of 20 different molecules used to build proteins.

annotation

The process of identifying the locations of genes in a genome and determining the role of those genes. Annotation is a process that often follows gene sequencing.

autosomal chromosomes
All of the human chromosomes except for the X and Y chromosomes.
autosomal dominant
A pattern of inheritance where having only copy of the gene that does not work correctly results in the condition, and the condition affects males and females equally.
autosomal recessive
A pattern of inheritance where copies of the gene that do not work properly are needed in order to have the condition, and the condition affects males and females equally.

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B

biobank

A collection of human biological samples (such as blood and tissue) and medical information about the people who gave their samples for research studies.

biomedicine

When the principles of natural sciences are used to evaluate and treat medical conditions.

biorepository

A collection of human biological samples (such as blood and tissue) and medical information about the people who gave their samples for research studies.

blinding

In a scientific experiment, a blind is where some of the people involved are prevented from knowing certain information that might lead to conscious or subconscious bias on their part, making the results not completely accurate.

blood sample

When blood is drawn from the human body in order to be tested for medical purposes.

BRCA 1 and 2

The first two genes found to be associated with inherited forms of breast cancer.

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C

cancer

A group of diseases characterized by uncontrolled cell growth. Cancer begins when a single cell mutates, resulting in a breakdown of the normal regulatory controls that keep cell division in check.

carrier
A person who has a change in only one gene of a pair and the other gene of the pair is working normally. Carriers typically do not display the symptoms of the condition, but can pass on the mutation to offspring.
carrier screening
A type of genetic testing to determine if an individual is a carrier for a genetic disease.
cell

The basic building blocks of all living things.

chromosome
An organized structure of DNA containing many genes that is wrapped around proteins found in cells. Humans typically have 23 pairs of chromosomes or 46 total.
chronic

Describes an illness that affects an individual for a long period of time, possibly their entire life.

chronic disease

A long-lasting health condition such as cancer, coronary heart disease, and diabetes.

CLIA

Clinical Laboratory Improvement Amendments are regulations created in 1988 by the Center for Medicare and Medicaid Services to ensure quality laboratory testing on humans.

clinical geneticist
A physician with training in genetics who meets with patients to evaluate, diagnose, and manage genetic disorders.
clinical testing

Testing that is done to confirm if a person has a condition.

cloning

Creating an organism that has the same genes as the original.

coinsurance
Your share of the costs of a covered healthcare service, calculated as a percentage of the allowed amount for the service
confirmatory test

Confirm or rule out a medical condition in an individual with concerning symptoms or an out-of-range screening result.

congenital

A condition that is present from birth.

copay
A fixed amount you pay for a covered healthcare service, usually when you get the service. The amount can vary by the type of covered health care service
copy number variation
When the number of copies of a particular gene varies from one individual to the next.
cytogenetics

The branch of genetics that studies the number and structure of human chromosomes.

cytosine

One of four chemical bases in DNA, denoted (C), with the other three being adenine (A), guanine (G), and thymine (T).

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D

deductible
The amount you owe for covered healthcare services before your health insurance plan begins to pay
deoxyribonucleic acid

DNA, a molecule found in chromosomes that carries genetic information. DNA is composed of four units (called bases) that are designated A, T, G, and C.

diagnostic genetic testing
Genetic testing used to identify if an individual has a condition associated with symptoms they are showing.
direct-to-consumer genetic testing

A type of genetic testing that is available directly to the consumer without having to go through a healthcare professional.

disorder

A disturbance in physical or mental health functions.

DNA
Deoxyribonucleic acid. A molecule found in chromosomes that carries genetic information. DNA is composed of four units (called bases) that are designated A, T, G, and C.
DNA replication

The process by which a molecule of DNA is duplicated.

DNA sequence
The sequence of the bases of DNA spell out instructions for making all of the proteins needed by an organism.
Dolly

The first mammal ever cloned (a sheep).

dominant

Individuals receive one version of a gene from each parent. Sometimes a version of a gene is dominant. Dominant genes have a more powerful effect than recessive genes and are thus more likely to be expressed or have a visible effect on the body.  If a dominant gene and a recessive gene are inherited, the effects of the dominant gene will mask those of the recessive gene. 

double helix
The twisted-ladder shape that two strands of DNA form.
Down syndrome
Also called trisomy 21. Down syndrome is a genetic disease in which a person inherits an extra copy of chromosome 21. The extra chromosome causes problems with the way the body and brain develop.
dried-blood-spot testing

Testing the small amount of dried blood on the filter paper cards used in newborn screening.

DTC

Direct-To-Consumer is a type of genetic test that is available directly to the consumer without having to go through a health care professional.

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E

emergency preparedness

The act of being prepared with your medical information in case an emergency event ever occurs.

endocrinologist

A doctor that specializes in disorders of the glands.

environmental factors
Chemicals, sun, and radiation that can cause mutations in DNA and can result in a disease that was acquired and not inherited.
enzyme
A protein that helps with chemical reactions in the body.
epigenetic markings
Changes in how the expression of a gene is regulated that is not caused by a change in the gene sequence.
epigenetics

An emerging field of science that studies heritable changes caused by the activation and deactivation of genes without any change in the underlying DNA sequence of the organism.

epigenome

It consists of chemical compounds that modify, or mark, the genome in a way that tells it what to do, where to do it, and when to do it.

eukaryote

A type of cell that has a nucleus and membrane-bound organelles.

exon

A section of DNA that serves as the set of instructions for constructing a protein.

expression

The process by which the information from a gene is translated and used to make a functional product, either a protein or a strand of RNA. When this occurs, the gene is said to have been expressed.

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F

false negative result

The result of a diagnostic test came back as normal when the disease is actually present. Tests are designed to make sure this type of mistake happens as little as possible.

false positive result

The result of a diagnostic test came back positive or abnormal when the disease is not actually present. Tests are designed to make sure this type of mistake happens as little as possible.

family health history
A record of medical information about an individual and their family members, as well as information about the eating habits, activities, and environments the family shares.
family tree
A record of members of a family and their relationships.
fatal

Causing death.

FDA

The Food and Drug Administration is the governmental organization responsible for protecting the public by assuring the safety, efficacy, and security of drugs, biological products, medical devices, food, and cosmetics. 

first degree relative

A family member who shares about 50 percent of their genes with a particular individual in a family. First degree relatives include parents, offspring, and siblings.

follow-up testing

Testing procedure that takes place after a positive or abnormal test result.  Follow-up testing is designed to limit false positive results.

fragile X syndrome

A genetic disorder caused by mutations in a gene on the X chromosome. Fragile X syndrome affects mostly males. It is the most common form of inherited intellectual disability (mental retardation). Other symptoms include distinctive facial features and poor muscle tone.

fraternal twins

Results from the fertilization of two separate eggs during the same pregnancy. Fraternal twins may be of the same or different sexes and they share half of their genes just like any other siblings.

frequency

The number of times something happens in a specific group.

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G

gene
A sequence of DNA that carries the instructions for making a sequence of RNA, which in turn instructs and assists in the creation of proteins.
gene regulation

The process of turning genes on and off, which ensures that the appropriate genes are expressed at the proper times.

gene therapy

An experimental technique for treating disease that works by introducing a healthy copy of a non-functioning gene into the patient's cells.

genetic code

The instructions in a gene that tell the cell how to make a specific protein. A, C, G, and T are the letters of the DNA code.

genetic counselor
A healthcare provider who has special training in genetic conditions. Genetic counselors help families understand genetic disorders and counsel families in making decisions about the testing or management of a genetic disorder.
genetic disease

A condition that is caused by changes in genes or chromosomes.

genetic disorder
A disease that is caused by an abnormality in an individual's DNA.
genetic map

Shows where genes are located relative to each other on chromosomes.

genetic marker

A DNA sequence with a known physical location on a chromosome. Genetic markers can help link an inherited disease with the responsible gene.

genetic testing
A laboratory test to look for a change in a gene of an individual. The results of a genetic test can be used to confirm or rule out a diagnosis of a genetic disease.
geneticist
A doctor or scientist who studies heredity and how genes work and contribute to disease.
genetics
The scientific study of how particular qualities or traits are passed down from parents to child.
genome

The complete DNA sequence in the chromosomes of an individual.

genomics

The study of the entire genome of an organism whereas genetics refers to the study of a particular gene.

genotype
A trait or gene that an individual inherits.
GINA

The Federal legislation passed in 2008 that makes it unlawful to discriminate against individuals based on their genes for health insurance or employment purposes.

guanine

One of four chemical bases in DNA, denoted (G), with the other three being adenine (A), cytosine (C), and thymine (T).

gynecologist

A doctor who specializes in the health care of women.

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H

Health Insurance Marketplace
A resource where individuals, families, and small businesses can: learn about their health coverage options; compare health insurance plans based on costs, benefits, and other important features; choose a plan; and enroll in coverage
healthcare provider
A doctor, nurse, physician’s assistant, or genetic counselor.
hereditary mutations
A change within a gene that can be passed to offspring.
heredity

The passing of traits from parents to offspring.

heterozygous

Refers to having inherited different forms of a particular gene from each parent.

histone

Proteins that DNA wraps around as it coils into chromosomes.  These proteins keep the DNA from becoming tangled and damaged.

homozygous

A genetic condition where an individual inherits the same alleles for a particular gene from both parents.

Human Genome Project

An international project that mapped and sequenced the entire human.

human subjects protections

The government has policies to protect people that participate in genetics research.

Huntington's disease
A genetic disorder that affects muscle coordination and brain function. Nerve cells in certain parts of the brain waste away, or degenerate, so it is called a neurodegenerative disorder. It is inherited through an autosomal dominant pattern.

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I

identical twins

Result from the fertilization of a single egg that splits in two. Identical twins share all of their genes and are always of the same sex.

immunity

An inherited, acquired, or produced resistance to infection by a specific pathogen.

immunization

The process of producing immunity to an infectious organism or agent in an individual or animal through vaccination.

immunologist

A doctor that specializes in conditions of the immune system.

in-range sreening result

The clinical test did not show any signs of conditions.

informed consent

Permission given by an individual to proceed with a specific test, procedure, or research study with an understanding of the risks and benefits of the activity.

inheritance

Passing of genes and traits from parents to child.

Institutional Review Board

The Institutional Review Board (IRB) makes sure that risks to people are as low as possible in a research study.

IRB

Makes sure that risks to people are as low as possible in a research study.

isolate DNA

To separate DNA from the other cell components.

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K

karyotype

Refers to an individual's full set of chromosomes. May also refer to a photographic representation of an individual’s chromosomes with all 23 pairs positioned next to one another.

knockout

Refers to an organism that has been genetically engineered such that one or more specific genes are inactivated or do not work properly. Scientists create knockouts (often in mice) so that they can study the impact of these genes when they do not function and learn something about the genes' function.

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L

linkage

The close association of genes or other DNA sequences on the same chromosome. The closer two genes are to each other on the chromosome, the greater the probability that they will be inherited together.

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M

Medicaid
An insurance program for families that have a low-income, pregnant women or people with disabilities that is paid for by the government
medical geneticist

A doctor who specializes in genetics and genetic disorders.

medical home

The facility or physician that coordinates the care of an individual with a complex medical condition.

Medicare
Medicare is an insurance program for people over 65 or people with End-Stage Renal Disease that is paid for by the government.
Mendelian inheritance

Refers to patterns of inheritance that are characteristic of organisms that reproduce sexually.

metabolic disorder

A disorder or defect in the way the body breaks down food or other products (metabolism).

methylation

When a base on the DNA strand is altered by the addition of a methyl group. This change causes that section of DNA to coil more tightly, preventing the genes around if from being used or expressed. This process is important as embryos develop and new cells take on specific roles in the body, but errors in DNA methylation have been linked to many human diseases.

mitochondria

Membrane-bound cell organelles that generate most of the chemical energy needed to power the cell's biochemical reactions.

mitochondrial inheritance
The mitochondrion, an organelle in the cell, contains its own genome. Mutations in these genes are responsible for several known genetic diseases. Individuals only inherit mitochondrial DNA from their mothers.
mitosis
The process occurring in cells where all the chromosomes are replicated and the cell contents are equally divided into two daughter cells.
model organisms

Organisms used in medical research to mimic a disease found in humans and to study its prevention, diagnosis, and treatment.
 

mutation
Any change that occurs in a gene. These may occur because of errors in the replication process or directly from the environment. Most mutations do not have any effect, some may have positive effects, and many have harmful effects.

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N

natural selection
The evolutionary process where the organism best adapted to it’s environment survives.
negative test result

A possible result of a screening or diagnostic test.  If the result came back from a genetic screening test, it means that the test did not find any evidence of the genetic condition for which it was testing.  If the result came back from a genetic diagnostic test, then the test did not find any evidence that the person has the genetic condition for which it was testing.

neonatal
During the first month of life.
newborn screening
A process of testing newborn babies for some serious, but treatable, conditions.
non-invasive

A medical test or procedure that does not require a doctor to insert any device through the skin or into a body opening.

nucleus

A membrane-bounded region inside each cell that provides a sanctuary for genetic information, including the long strands of DNA that encode this genetic information.

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O

oncogene

A mutated gene that contributes to the development of a cancer.

opt-out

A patient's right to refuse screening tests.

organ

A collection of tissues that structurally form a functional unit specialized to perform a particular function. Your heart, kidneys, and lungs are examples of organs.

organelle

A subcellular structure that has one or more specific jobs to perform in the cell, much like an organ does in the body.

out-of-pocket costs
Your expenses for medical care that aren't reimbursed by insurance. Out-of-pocket costs include deductibles, coinsurance, and copayments for covered services plus all costs for services that aren't covered
out-of-range result

This result means that the screening test did show signs that the individual may be at higher risk of having one or more conditions.

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P

patient confidentiality

The right of an individual patient to have personal, identifiable medical information kept private.

pediatrician

A primary care physician who specializes in the medical care of infants, children, and adolescents.

pedigree

A genetic representation of a family tree that diagrams the inheritance of a trait or disease though several generations.

pharmacogenetics
The study of how genetics determine drug behavior and why some drugs work differently between individuals.
phenotype
An individual's observable characteristics or traits.
physician

A person licensed to practice medicine, also known as a medical doctor.

positive screen (positive test result)

A possible result of a screening or diagnostic test. If the result came back from a genetic screening test, further testing must be done to determine if the person has the condition which was being tested for.  If the result came back from a genetic diagnostic test, then the person has the condition and can pursue treatment options for that condition.

predictive genetic test
A genetic test for individuals not yet showing symptoms of a genetic disorder but have a family history of the condition or an increased risk of developing the condition.
predispositional

Symptoms are likely, but not certain to develop if testing suggests you have disease gene.

Premium
the set dollar amount you pay each month to receive insurance coverage
prenatal

Anytime before the birth of the baby.

prenatal care providers

Healthcare professionals who aid a woman throughout her pregnancy.

presymptomatic
You will eventually develop symptoms if testing suggests you have the disease gene.
primary care provider

A doctor trained to treat a wide variety of health-related problems.

privacy protections

Ensure that blood spots cannot be accessed by a third party, including insurers and law enforcement.

Progeria

A rare disease characterized by accelerated aging.

prokaryote

A type of cell that does not have a nucleus or membrane-bound organelles.

prostate cancer

A disease characterized by uncontrolled cell growth in the prostate gland, which is part of the male reproductive system.

protein

Proteins make up many parts of every cell in the body. Proteins are made up of amino acids. The order of these amino acids determines what form and job a protein has.

protein sequencing
The process of determining the order of amino acids (the molecules that make up proteins) of a particular protein.
public health

The science and practice of protecting and improving the health of a community.

pulmonologist

A doctor that specializes in lung conditions and diseases.

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Q

quality assurance

Process of defining the quality of performance required for each step in the testing process.

quality control

Monitoring the degree of adherence to defined criteria, taking corrective action when the system fails and documenting all of these events to convey the total quality of performance.

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R

rare health conditions

An uncommon disorder that affects the ability of the human body to function normally.

recessive

A quality found in the relationship between two versions of a gene. Individuals receive one version of a gene, called an allele, from each parent. If the alleles are different, the dominant allele will be expressed, while the effect of the other allele, called recessive, is masked. In the case of a recessive genetic disorder, an individual must inherit two copies of the mutated allele in order for the disease to be present.

referral

Individuals receive one version of a gene from each parent. Sometimes a version of a gene is recessive. Recessive genes have a less powerful effect than dominant genes.  If a dominant gene and a recessive gene are inherited, the effects of the recessive gene are not visible or are masked by the more powerful dominant gene’s effects.  If two recessive genes are inherited, then the effects of the recessive genes are visible.

registry

A collection of medical information, clinical data, and demographics (age, male or female, etc.) about people with a specific disease or condition.

research geneticist
Geneticists who focus on research and study the origin, treatment, and prevention of genetic conditions.
retesting

When a test needs to be repeated in order to clarify, confirm or reject the results of the initial test.

ribonucleic acid

RNA, a molecule similar to DNA. Unlike DNA, RNA is single-stranded. An RNA strand has a backbone made of alternating sugar (ribose) and phosphate groups. Attached to each sugar is one of four bases--adenine (A), uracil (U), cytosine (C), or guanine (G).

RNA

Ribonucleic acid, a molecule similar to DNA. Unlike DNA, RNA is single-stranded. An RNA strand has a backbone made of alternating sugar (ribose) and phosphate groups. Attached to each sugar is one of four bases--adenine (A), uracil (U), cytosine (C), or guanine (G).

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S

SCID

Severe Combined Immunodeficiency is an inherited condition affecting the immune system causing individuals to be more susceptible to infectious diseases.

screening tests
Tests that analyze DNA samples to detect the presence of a gene or genes associated with an inherited disorder.
sequencing

DNA sequencing is a detailed description of the order of the chemical buildings blocks, or bases, in a given stretch of DNA. The sequence of bases tells scientists the type of genetic information that is carried in a particular segment of DNA.

sex chromosome

A sex chromosome is a type of chromosome that participates in sex determination. Humans have two sex chromosomes, the X and the Y. Females have two X chromosomes in their cells, while males have both X and a Y chromosomes in their cells.

sex linked

A trait in which a gene is located on a sex chromosome.

sickle cell anemia
A disorder that is passed down through families and causes red blood cells to form an abnormal crescent, or sickle, shape. These sickled red blood cells cannot carry enough oxygen to the body. It is inherited in the autosomal recessive pattern.
single nucleotide polymorphisms (SNPs)

A type of polymorphism involving variation of a single base pair. Scientists are studying how single nucleotide polymorphisms, or SNPs (pronounced snips), in the human genome correlate with disease, drug response, and other phenotypes.

social worker

A trained professional who provides social services to those in need.

somatic cells
Any cell in the body except for sperm and egg cells.
specialist

A healthcare provider who has special knowledge about a condition or a specific part of a condition.

standard medical procedure

Surgery or practice that is a common and well accepted as the best course of treatment.

state assistance

Payment given to individuals by government agencies on the basis of need.

stem cell

A cell with the potential to form many of the different cell types found in the body.

support group

A group of people who are all impacted by the same condition and come together to share experiences and help one another.

symptom

Evidence of a disorder or disease that directly affects and is noticed by the patient, such as a rash, pain, nausea, or a runny nose.

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T

tanscription

The process within the cell that uses DNA instructions to create pieces of RNA, which can then be used to make proteins or perform other tasks throughout the body.

testing outcomes

The possible results you can receive after participating in a test such as positive, negative, or inconclusive.

thymine

One of four chemical bases in DNA, denoted (T), with the other three being adenine (A), cytosine (C), and guanine (G).

trait
A specific characteristic of an individual.
transcription factor

Proteins that bind to specific sections of DNA and control transcription or the process of using DNA instructions to create new strands of RNA. 

transition process

The time when an individual with a genetic condition or special healthcare needs must change his or her system of care to reflect his or her age. After reaching adolescence or adulthood an individual will likely need to change health care providers, most likely from a pediatrician to an adult physician.

treatable condition

A condition with a known treatment that can improve the survival and/or quality of life of an individual.

true positive result

A small percentage of individuals with out-of-range results do have the condition and must pursue treatment options.

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U

uracil

One of four chemical bases that are part of RNA, denoted (U). The other three bases are adenine (A), cytosine (C), and guanine (G).

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V

virus

An infectious agent that occupies a place near the boundary between the living and the nonliving.Viruses enter host cells and hijack the enzymes and materials of the host cells to make more copies of themselves.

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W

whole genome sequencing

Whole genome sequencing is the mapping out of a person’s unique DNA. Your genome is the unique blueprint for your body.

working copy
A gene that functions the way it is intended to.

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X

X chromosome

One of two sex chromosomes. Humans have two sex chromosomes, the X and the Y. Females have two X chromosomes in their cells. Males have X and Y chromosomes in their cells.

X-linked dominant
An inheritance pattern where X-linked means that the disease gene is located on the X sex chromosome and dominant means that having only one copy of the gene that does not work properly causes the condition. Affects more females than males.
X-linked recessive
An inheritance pattern where X-linked means that the disease gene is located on the X sex chromosome and recessive means that two copies of the gene that does not work properly are needed to have the condition. Affects more males than females.

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Y

Y chromosome

One of two sex chromosomes. Humans have two sex chromosomes, the X and the Y. Males have X and Y chromosomes in their cells.

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