How does an epigenetic change differ from a mutation?

A mutation is heritable. Epigenetic changes affect only the cells in which they occur during the cell's lifetime.

A mutation alters the nucleotide sequence in DNA. An epigenetic change does not alter the DNA sequence, but can be inherited by daughter cells.

Epigenetic changes occur due to environmental effects and only persist as long as the environment that induced them remains constant. Mutations are permanent.

Mutations involve nucleotide sequences of only one or a few base pairs. An epigenetic change involves large regions of a chromosome, thousands of base pairs or more in length.