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 A genetic disorder is an illness caused by changes in a personâs DNA.  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.