Why mutations are harmful

When determining if a gene variant is associated with a genetic disorder, the variant is evaluated using scientific research to date, such as information on how the variant affects the function or production of the protein that is made from the gene and previous variant classification data. The variant is then classified on a spectrum based on how likely the variant is to lead to the disorder. Evaluation needs to be done for each variant. Just because a gene is associated with a disease, does not mean that all variants in that gene are pathogenic.

Additionally, evaluation of a variant needs to be done for all diseases with which it is thought to be associated. A variant that is pathogenic for one disease, is not necessarily pathogenic for a different disease. It is important to re-evaluate variants periodically; the classification of a variant can change over time as more information about the effects of variants becomes known through additional scientific research. Standards and guidelines for the interpretation of sequence variants: a joint consensus recommendation of the American College of Medical Genetics and Genomics and the Association for Molecular Pathology.

Genet Med. Epub Mar 5. Other chapters in Help Me Understand Genetics. Genetics Home Reference has merged with MedlinePlus. Learn more. The information on this site should not be used as a substitute for professional medical care or advice.

Contact a health care provider if you have questions about your health. Do all gene variants affect health and development? What kinds of gene variants are possible? Can a change in the number of genes affect health and development? Can changes in the number of chromosomes affect health and development? Can changes in the structure of chromosomes affect health and development? Can changes in noncoding DNA affect health and development?

Can changes in mitochondrial DNA affect health and development? What are complex or multifactorial disorders? What does it mean to have a genetic predisposition to a disease? Mutations can be inherited or acquired during a person's lifetime. Mutations that an individual inherits from their parents are called hereditary mutations.

They are present in all body cells and can be passed down to new generations. Once an acquired mutation is passed down, it is a hereditary mutation. Acquired mutations are not passed down if they occur in the somatic cells, meaning body cells other than sperm cells and egg cells. Some acquired mutations occur spontaneously and randomly in genes. Other mutations are caused by environmental factors, such as exposure to certain chemicals or radiation.

Mutations occur throughout the natural world. Some mutations are beneficial and increase the possibility that an organism will thrive and pass on its genes to the next generation. When mutations improve survival or reproduction, the process of natural selection will cause the mutation to become more common over time. When mutations are harmful, they become less common over time. Therefore, mutation is a force that helps drive evolution. The audio, illustrations, photos, and videos are credited beneath the media asset, except for promotional images, which generally link to another page that contains the media credit.

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