How and when does genetic mutation occur? Name one condition that is the result of genetic mutation?

Genetic Mutation
How and when does genetic mutation occur? Name one condition that is the result of genetic mutation?Please reference this book as one of the scholarly references: Hubert, R. & VanMeter, K. (2018). Gould’s pathophysiology for the health professions: Study Guide (6th ed.). St. Louis, MO: Elsevier.