Does every member of a familial GIST kindred have the mutation?
No, not every member of a kindred with familial GIST will inherit the familial mutation. We all typically have two copies of every gene: we inherit one copy of a gene from our mother and the other copy of a gene from our father. Similarly, if we have children, we pass on one of our two copies of a gene to each child and our partner contributes one of his/her two copies of a gene to make a complete set in a child. A person with a germ-line mutation in one of his or her c-kit or PDGFRA genes has a 50% (or 1 in 2) chance of passing on the same germ-line mutation to each of his or her children, with an equal 50% chance of passing on his or her unaltered copy of the gene. Mutations in the c-kit and PDGFRA genes can be inherited from your mother or from your father, and they are passed on to daughters and to sons equally. This is called an autosomal dominant pattern of inheritance. Relatives who inherited the familial c-kit or PDGFRA germ-line mutation would be at increased risk to develop G
