Gene mutation

Gene mutation is a permanent alteration in the DNA sequence that makes up a gene, such that the sequence differs from what is found in most people. Mutations range in size; they can affect anywhere from a single DNA building block (base pair) to a large segment of a chromosome that includes multiple genes.

Types of mutations

Gene mutations can be classified in two major ways:

• Hereditary mutations are inherited from a parent and are present throughout a person’s life in virtually every cell in the body. These mutations are also called germline mutations because they are present in the parent’s egg or sperm cells, which are also called germ cells. When an egg and a sperm cell unite, the resulting fertilized egg cell receives DNA from both parents. If this DNA has a mutation, the child that grows from the fertilized egg will have the mutation in each of his or her cells.
• Acquired (or somatic) mutations occur at some time during a person’s life and are present only in certain cells, not in every cell in the body. These changes can be caused by environmental factors such as ultraviolet radiation from the sun, or can occur if a mistake is made as DNA copies itself during cell division. Acquired mutations in somatic cells (cells other than sperm and egg cells) cannot be passed on to the next generation.

Causes of mutations

Mutations may be caused by many factors including:

• Environmental factors such as smoking, radiation, viruses, cancer-causing chemicals (carcinogens), obesity, hormones, chronic inflammation, and a lack of exercise.
• Errors that occur when DNA is copied during cell division.

Effects of mutations

The effects of mutations can vary widely. Some mutations do not cause any noticeable changes in the body, while others can lead to genetic disorders such as cystic fibrosis, sickle cell anemia, Marfan syndrome, Huntington's disease and hemochromatosis. Mutations can also increase the risk of developing certain types of cancer.

Prevention and treatment

While it is not possible to prevent gene mutations that are inherited, it is possible to reduce the likelihood of somatic mutations by reducing exposure to environmental factors that can cause these changes. Treatment for diseases caused by mutations depends on the specific disease. In some cases, gene therapy may be a potential treatment.

See also

• DNA
• Genetic disorder
• Cancer
• Gene therapy

Gene mutation Resources
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