NCI Dictionary of Genetics Terms

14 results found for: T

TDR: A first cousin, great-grandparent, great-aunt, great-uncle, great-niece, great-nephew, great-grandchild, half-aunt, or half-uncle of an individual. Also called third-degree relative.
telomere: (TEH-loh-meer); The end of a chromosome. Telomeres are made of repetitive sequences of non-coding DNA that protect the chromosome from damage. Telomeres become shorter each time the cell divides.
third-degree relative: (... deh-GREE REH-luh-tiv); A first cousin, great-grandparent, great-aunt, great-uncle, great-niece, great-nephew, great-grandchild, half-aunt, or half-uncle of an individual. Also called TDR.
throughput: (THROO-put); The amount of information, people, or materials that is put through a process during a specific period of time. In medicine, throughput can be used to describe the number of laboratory tests, such as genetic sequencing, performed or the number of patients seen in a clinic during a certain period of time.
TNBC: TNBC is defined by a lack of expression of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2/neu). Also called ER-negative PR-negative HER2/neu-negative breast cancer and triple-negative breast cancer.
transcription: (tran-SKRIP-shun); The process of synthesizing messenger RNA (mRNA) from DNA.
translation: (trans-LAY-shun); The process of synthesizing an amino acid sequence (protein product) from the messenger RNA (mRNA) code.
translocation: (TRANZ-loh-KAY-shun); A type of chromosomal abnormality in which a chromosome breaks and a portion of it reattaches to a different chromosomal location.
trichilemmoma: (TRIH-kih-leh-MOH-muh); A benign tumor arising from the outer cells of the hair follicle.
trinucleotide repeat: (try-NOO-klee-oh-tide reh-PEET); A sequence of three nucleotides that is repeated a number of times in a row in a segment of DNA. A certain amount of variation in the number of trinucleotide repeats is common and usually does not cause disease in individuals. But too many copies of certain trinucleotide repeats in the DNA can affect the gene's function, which could lead to certain genetic disorders. The number of trinucleotide repeats can change as the gene is passed from parent to child.
triple-negative breast cancer: (TRIH-pul-NEH-guh-tiv brest KAN-ser); Triple-negative breast cancer is defined by a lack of expression of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2/neu). Also called ER-negative PR-negative HER2/neu-negative breast cancer and TNBC.
trisomy: (TRY-soh-mee); The presence of an extra chromosome in some or all of the body's cells. This results in a total of three copies of that chromosome instead of the normal two copies. For example, Down syndrome (trisomy 21) is caused by having three copies of chromosome 21 instead of the usual two copies.
tumor DNA sequencing: (TOO-mer ... SEE-kwen-sing); Sequencing of somatic tissue, such as tumors, refers to looking for variants in DNA that typically occur after conception. Somatic mutations can occur in any of the cells of the body except the germ cells (sperm and egg) and therefore are not passed on to children. These variants can (but do not always) cause cancer or other diseases.
tumor suppressor gene: (TOO-mer suh-PREH-ser jeen); A type of gene that regulates cell growth. When a tumor suppressor gene is mutated, uncontrolled cell growth may occur. This may contribute to the development of cancer. Also called antioncogene.