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 an inherited mutation, which is 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.