NCI Dictionary of Genetics Terms

13 results found for: A

acrochordon: (A-kroh-KOR-dun); A small, benign skin growth that may have a stalk (peduncle). Acrochordons most commonly appear on the neck, axillary, groin, and inframammary regions. Also called skin tag.
affected individual: (uh-FEK-ted in-dih-VIH-joo-wul); In genetics, describes an individual who has a particular phenotypic trait or disease. The individual expresses the trait or has signs and symptoms of the disease.
allele: (uh-LEEL); One of two or more versions of a genetic sequence at a particular region on a chromosome. An individual inherits two alleles for each gene, one from each parent.
allelic heterogeneity: (uh-LEE-lik HEH-teh-roh-jeh-NEE-ih-tee); The presence of different variants at a single gene locus that cause the same or similar phenotypic expressions of a disease or condition.
aneuploidy: (AN-yoo-PLOY-dee); The occurrence of one or more extra or missing chromosomes in a cell or organism. Aneuploidy refers to any chromosome number that is not an exact multiple of the haploid number of chromosomes (which is 23 in humans).
antioncogene: (AN-tee-ON-koh-jeen); A type of gene that regulates cell growth. When an antioncogene is mutated, uncontrolled cell growth may occur. This may contribute to the development of cancer. Also called tumor suppressor gene.
ART: Procedures that use donor or nondonor eggs and sperm to create embryos in vitro. Examples of ART include in vitro fertilization (IVF), gamete intrafallopian transfer (GIFT), and zygote intrafallopian transfer (ZIFT). These procedures may be used prior to preimplantation genetic testing (PGT). Also called assisted reproductive technology.
Ashkenazi Jews: (ASH-keh-NAH-zee jooz); One of two major ancestral groups of Jewish people whose ancestors lived in France and Central and Eastern Europe, including Germany, Poland, and Russia. The other group is called Sephardic Jews and includes those whose ancestors lived in Spain, Portugal, North Africa, and the Middle East. Most Jewish people living in the United States are of Ashkenazi descent.
assisted reproductive technology: (uh-SIS-ted REE-proh-DUK-tiv tek-NAH-loh-jee); Procedures that use donor or nondonor eggs and sperm to create embryos in vitro. Examples of assisted reproductive technology include in vitro fertilization (IVF), gamete intrafallopian transfer (GIFT), and zygote intrafallopian transfer (ZIFT). These procedures may be used prior to preimplantation genetic testing (PGT). Also called ART.
attributable risk: (uh-TRIH-byoo-tuh-bul …); Proportion of a disease in exposed individuals that can be attributed to an exposure. In the context of genetic studies, the "exposure" is the frequency of a specific genetic variant.
autosomal: (AW-toh-SOH-mul); Having to do with any of the 22 numbered pairs of chromosomes found in most human cells. Autosomal chromosomes are numbered 1-22. The sex chromosomes (X and Y chromosomes) determine whether an individual is male or female and are not considered autosomal chromosomes.
autosomal dominant inheritance: (AW-toh-SOH-mul DAH-mih-nunt in-HAYR-ih-tunts); One of the ways a genetic trait or a genetic condition can be inherited. In autosomal dominant inheritance, a genetic condition occurs when a variant is present in only one allele (copy) of a given gene.
autosomal recessive inheritance: (AW-toh-SOH-mul reh-SEH-siv in-HAYR-ih-tunts); One of the ways a genetic trait or a genetic condition can be inherited. In autosomal recessive inheritance, a genetic condition occurs when one variant is present on both alleles (copies) of a given gene.