Autoimmune hepatitis is a disease in which the bodyâs immune system attacks liver cells of the same organism. This causes the liver to become inflamed, resulting in hepatitis.
1 Gene mutations that occur after birth. 2  Most gene mutations occur after you're born and aren't inherited. 3  A number of forces can cause gene mutations, such as smoking, radiation, viruses, cancer-causing chemicals (carcinogens), obesity, hormones, chronic inflammation and a lack of exercise.
Genetic mutations. Genetic mutations occur when DNA changes, altering the genetic instructions. This may result in a genetic disorder or a change in characteristics. Mutations can be caused by exposure to specific chemicals or radiation. For example, cigarette smoke is full of chemicals that attack and damage DNA.This causes mutations in lung cell genes, including the ones that control growth.utations can be caused by exposure to specific chemicals or radiation. For example, cigarette smoke is full of chemicals that attack and damage DNA. This causes mutations in lung cell genes, including the ones that control growth.