NCI Dictionary of Genetics Terms

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The NCI Dictionary of Genetics Terms contains technical definitions for more than 200 terms related to genetics. These definitions were developed by the PDQ® Cancer Genetics Editorial Board to support the evidence-based, peer-reviewed PDQ cancer genetics information summaries.

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12 results found for: D
D’Amico criteria
(DEE-uh-MEE-koh kry-TEER-ee-uh)
A set of clinical criteria that is used to stratify prostate cancers into three risk categories to estimate cancer growth and spread. The criteria include Gleason score, prostate-specific antigen level, and clinical stage at diagnosis.
de novo mutation
(deh NOH-voh myoo-TAY-shun)
An alteration in a gene that is present for the first time in one family member as a result of a mutation in a germ cell (egg or sperm) of one of the parents, or a mutation that arises in the fertilized egg itself during early embryogenesis. Also called new mutation.
de novo variant
(deh NOH-voh VAYR-ee-unt)
A genetic alteration that is present for the first time in one family member as a result of a variant (or mutation) in a germ cell (egg or sperm) of one of the parents, or a variant that arises in the fertilized egg itself during early embryogenesis. Also called de novo mutation, new mutation, and new variant.
deleterious mutation
(DEH-leh-TEER-ee-us myoo-TAY-shun)
A mutation that is documented to be associated with risk of disease.
deletion
(deh-LEE-shun)
A type of genetic change that involves the absence of a segment of DNA. It may be as small as a single base but can vary significantly in size.
deoxyribonucleic acid
(dee-OK-see-RY-boh-noo-KLAY-ik A-sid)
The molecular basis of heredity; encodes the genetic information responsible for the development and function of an organism and allows for transmission of that genetic information from one generation to the next. The DNA molecule is structured as a double-stranded helix held together by weak hydrogen bonds between purine-pyrimidine nucleotide base pairs: adenine (A) paired with thymine (T), and guanine (G) paired with cytosine (C). Also called DNA.
depth of coverage
(... KUH-veh-rij)
Refers to the number of times a nucleotide is read during sequencing. A greater depth of coverage can increase confidence in the final results. Deep coverage aids in differentiating sequencing errors from single nucleotide polymorphisms. This can be specifically useful when a patient has a mosaicism or when a tumor is heterogeneous for a mutation.
dirty necrosis
(DIR-tee neh-KROH-sis)
Presence of necrotic cellular debris within the lumen of the neoplastic glands in the colorectal mucosa.
disease-causing mutation
(dih-ZEEZ-KAW-sing myoo-TAY-shun)
A gene alteration that causes or predisposes an individual to a specific disease.
DNA
The molecular basis of heredity; encodes the genetic information responsible for the development and function of an organism and allows for transmission of that genetic information from one generation to the next. The DNA molecule is structured as a double-stranded helix held together by weak hydrogen bonds between purine-pyrimidine nucleotide base pairs: adenine (A) paired with thymine (T), and guanine (G) paired with cytosine (C). Also called deoxyribonucleic acid.
domain
(doh-MAYN)
A specific physical region or amino acid sequence in a protein which is associated with a particular function or corresponding segment of DNA.
double heterozygosity
(DUH-bul HEH-teh-roh-zy-GAH-sih-tee)
The presence of two different mutated alleles at two separate genetic loci.