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.
However, mutation can also disrupt normal gene activity and cause diseases, like cancer Cancer is the most common human genetic disease; it is caused by mutations occurring in a number of growth-controlling genes. Sometimes faulty, cancer-causing genes can exist from birth, increasing a personâs chance of getting cancer. An illustration to show an example of a DNA mutation.