How Are Mutations Inherited?

How Mutations Are Inherited

People can pass an inherited gene mutation to their children through their sperm or eggs. When a person with a gene mutation has children, each child has a 50 percent chance of inheriting the same mutation.  

Mapping your family medical history

Genetics experts look carefully at a family’s medical history for signs of hereditary cancer. You can assist them by gathering medical information from relatives on both sides of your family going back as far as three or more generations if possible. They will use this information to create a diagram of your family tree known as a pedigree. This allows them to look for patterns that may indicate an inherited mutation and determine which relatives are at increased risk for cancer. 

“Degree of relatedness” is a term used by experts to describe how closely related one family member is to another. "First-degree relatives” share half of their DNA. If a person has an inherited mutation, each of their first degree relatives has a 50 percent chance of testing positive for the same mutation. Second-degree relatives share one fourth of their DNA, third-degree relatives share one eigth of their DNA, and so on.