What is a germ-line mutation and how does it cause hereditary GIST?
A mutation is a change in the pattern of a gene’s DNA that prevents the gene from working properly. If you think of a gene as similar to a sentence, DNA is like the letters that make up the words in that sentence. Just as you can have a misspelling in a word in a sentence, you can have a misspelling (or “mutation”) in the DNA of one of your genes. Unlike a somatic mutation (which is acquired over your lifetime and is present only in tumor cells), a germ-line mutation is usually passed to you by your mother or father, and can be passed on to your children. Germ-line mutations can, therefore, be carried by multiple family members. Each family (or “kindred”) with hereditary GIST may have its own unique germ-line mutation in a cancer susceptibility gene. Although the location of the germ-line mutation may be different from one family to another, the mutation will remain constant within a family: that is, the location of the mutation within the gene is the same for each member of a family.
