Constitutional (also known as germline) variants are present in all the body’s cells, including the germ cells, and can therefore be passed on to offspring e.g. Lynch Syndrome; Somatic variants arise during an individual’s lifetime in tissues other than the germ cells and so are not passed on.
Constitutional (germline) variants in cancer predisposition genes are present in affected individuals in all the body’s nucleic cells, as well as the cancer genome, and may therefore be inherited. These underlie inherited cancer predisposition syndromes, such as Lynch syndromeand hereditary breast and ovarian cancer syndrome.
Lynch Syndrome Ireland 