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.
1 These mutations can be due to an error in DNA replication or due to environmental factors, such as cigarette smoke and exposure to radiation, which cause changes in the DNA sequence.2  The human genome is a complex set of instructions, like a recipe book, directing our growth and development. genetic disorder is a disease that is caused by a change, or mutation, in an individualâs DNA sequence.