ataxia-telangiectasia mutation [a-tax-ee-yuh tel-an-jee-eck-TAY-zhuh]

also called ATM. An inherited mutation in a certain gene responsible for repairing damaged deoxyribonucleic acid (DNA). If this mutation is present, the carrier may have a higher risk of several types of cancer. See also deoxyribonucleic acid, gene, genetic testing, mutation.


mutation [mew-tay-shun]

a change in the deoxyribonucleic acid (DNA) of a cell. Most mutations do not cause cancer, and a few may even be helpful. But all types of cancer are thought to be due to mutations that damage a cell’s DNA. Some cancer-related mutations can be inherited (passed on from a parent). This means that the person is born with the mutated DNA in all the body’s cells. But most mutations happen after the person is born. These are called somatic or acquired mutations. This type of mutation happens in one cell at a time, and only affects cells that arise from the single mutated cell. See also cancer susceptibility genes, deoxyribonucleic acid, gene, inherited mutation, somatic mutation.


somatic mutation [so-mat-ick mew-tay-shun]

a change in deoxyribonucleic acid (DNA) that starts in one cell of the body at any time of life after an embryo is formed. All the cells that arise from that cell will typically have the same mutation, which in some cases can lead to cancer. This kind of mutation is different from inherited mutations, which are present at birth and in all the cells of the body. Somatic mutations are not passed on to children. Compare to inherited disease. See also deoxyribonucleic acid, mutation.