A gene mutation is a permanent change in the DNA sequence that makes up a gene. Gene mutations can be inherited from a parent or can happen during a person’s lifetime. Mutations passed from parent to child are called hereditary mutations. Mutations that happen during a person’s life can be caused by environmental factors such as ultraviolet radiation from the sun. Or they can occur if a mistake is made as DNA copies itself during cell division. Some gene mutations may influence the risk of developing certain disorders, including cancer.