10 results found for: N
-
negative predictive value
(NEH-guh-tiv preh-DIK-tiv VAL-yoo)
The likelihood that an individual with a negative test result is truly unaffected and/or does not have the particular gene mutation in question. Also called NPV. -
new mutation
(noo 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 de novo mutation. -
noncarrier
(non-KAYR-ee-er)
An individual who does not carry a mutation previously identified in his or her family. -
nonpenetrance
(non-PEH-neh-trunts)
The state in which a genetic trait, although present in the appropriate genotype, fails to manifest itself in the phenotype (e.g., a woman with a BRCA1 mutation who lives to be elderly and never develops breast or ovarian cancer). -
nonsense mutation
(NON-sens myoo-TAY-shun)
A mutation that alters the genetic code in a way that causes the premature termination of a protein. The altered protein may be partially or completely inactivated, resulting in a change or loss of protein function. -
novel mutation
(NAH-vel myoo-TAY-shun)
A newly discovered, distinct gene alteration; NOT the same as new or de novo mutation. -
NPV
The likelihood that an individual with a negative test result is truly unaffected and/or does not have the particular gene mutation in question. Also called negative predictive value. -
nucleotide
(NOO-klee-oh-tide)
A molecule consisting of a nitrogen-containing base (adenine, guanine, thymine, or cytosine in DNA; adenine, guanine, uracil, or cytosine in RNA), a phosphate group, and a sugar (deoxyribose in DNA; ribose in RNA). DNA and RNA are polymers comprised of many nucleotides, strung together like beads in a necklace. -
null allele
(nul uh-LEEL)
A mutation that results in either no gene product or the absence of function at the phenotypic level. -
nutrigenomics
(NOO-trih-jeh-NOH-mix)
The study of the interaction of dietary and genetic factors and its effect on metabolism, health status, and risk of disease.