Mutation, hereditary: A heritable change in the DNA of a gene or chromosome in a cell destined to become an egg or a sperm or the zygote (the conceptus) at the single-cell stage. When transmitted to a child, an hereditary mutation is incorporated in every cell of their body.
Hereditary mutations play a key role in genetic diseases. They also play a role in certain types of cancer as, for example, the eye tumor retinoblastoma and Wilms tumor, a childhood malignancy of the kidney.
Hereditary mutations are also called germline mutations.