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Glossary of Terms

Most of the following definitions, and additional information about these terms, can be found on the US National Library of Medicine Web site.

Allele
Variant forms of the same gene. Different alleles produce variations in inherited characteristics such as eye color or blood type.

Amino acid
A group of 20 different kinds of small molecules that link together in long chains to form proteins. Often referred to as the "building blocks" of proteins.

Autoimmune disease
A condition in which the body recognizes its own tissues as foreign and directs an immune response against them.

Cloning
The process of making copies of a specific piece of DNA, usually a gene. When geneticists speak of cloning, they do not mean the process of making genetically identical copies of an entire organism.

DNA or deoxyribonucleic acid
The molecules inside cells that carry genetic information and pass it from one generation to the next.

Environmental factors
Factors besides those with which you are born that influence your health, such as background or lifestyle. Factors might include diet, exercise or smoking history, as well as the air we breathe.

Epidemiology
The study of populations in order to determine the frequency and distribution of disease and measure risks.

Gene
The functional and physical unit of heredity passed from parent to offspring. Genes are pieces of DNA, and most genes contain the information for making a specific protein.

Genotype
The genetic identity of an individual that does not show as outward characteristics.

Genetic code
The instructions in a gene that tell the cell how to make a specific protein. A, T, G, and C are the "letters" of the DNA code; they stand for the chemicals adenine, thymine, guanine, and cytosine, respectively, that make up the nucleotide bases of DNA. Each gene's code combines the four chemicals in various ways to spell out 3-letter "words" that specify which amino acid is needed at every step in making a protein.

Genetic Engineering
A variety of techniques that molecular biologists use to manipulate DNA molecules to study the expression of a gene.

Genetic testing
Analyzing an individual's genetic material to determine predisposition to a particular health condition or to confirm a diagnosis of genetic disease.

Genetic traits (trait)
An inherited characteristic, such as eye color.

Genetic variation
The phenotypic and genotypic differences among individuals in a population.

Genetics
The branch of science concerned with the means and consequences of transmission and generation of the components of biological inheritance.

Health Information Portability and Accountability Act (HIPAA)
This Act requires, among other things, under the Administrative Simplification subtitle, the adoption of standards, including standards for protecting the privacy of individually identifiable health information.

Information for patients on the HIPAA Privacy Rule and how it relates to research can be found National Institutes of Health HIPAA Privacy Rule.

Human Genome Project
An international research project to map each human gene and to completely sequence human DNA.

Inheritance
Traits or characteristics that are transmitted through genes that have been passed from parents to their offspring (children).

Mutation
Any alteration in a gene from its natural state; may be disease causing or a benign, normal variant.

Nucleotide
One of the structural components, or building blocks, of DNA and RNA. A nucleotide consists of a base (one of four chemicals: adenine, thymine, guanine, and cytosine) plus a molecule of sugar and one of phosphoric acid.

Phenotype
The observable traits or characteristics of an organism, for example hair color, weight, or the presence or absence of a disease. Phenotypic traits are not necessarily genetic.

PHI (protected health information)
PHI is individually identifiable health information transmitted by electronic media, maintained in electronic media, or transmitted or maintained in any other form or medium. PHI excludes education records covered by the Family Educational Rights and Privacy Act, as amended, 20 U.S.C. 1232g, records described at 20 U.S.C. 1232g(a)(4)(B)(iv), and employment records held by a covered entity in its role as employer.

Predisposed (genetic predisposition)
Increased susceptibility to a particular disease due to the presence of one or more gene mutations, and/or a combination of alleles (haplotype), not necessarily abnormal, that is associated with an increased risk for the disease, and/or a family history that indicates an increased risk for the disease

Protein
A molecule made up of amino acids that are needed for the body to function properly. Proteins are the basis of body structures such as skin and hair and of substances such as enzymes, cytokines, and antibodies.

Risk factor
Something that may increase the chance of developing a disease. Some examples of risk factors for cancer include age, a family history of certain cancers, use of tobacco products, certain eating habits, obesity, lack of exercise, exposure to radiation or other cancer-causing agents, and certain genetic changes.

Stem cells
Cells from which other types of cells can develop.

Variations (genetic variation)
The phenotypic and genotypic differences among individuals in a population.

Waiver
The documentation that the covered entity obtains from a researcher or an IRB or a Privacy Board that states that the IRB or Privacy Board has waived or altered the Privacy Rule's requirement that an individual must authorize a covered entity to use or disclose the individual's PHI for research purposes.