Every person has changes in his or her genome that make him or her unique. Most of these changes do not have any effect on our physical appearance, risk for diseases, or our behavior. Sometimes, however, they do have an effect.
There are several different types of changes researchers may find in a person’s genome:
- Normal (neutral) variations: changes in a gene that are not known to cause health, developmental, or behavior problems. Genetic variations are found in every person who might have whole exome sequencing (a type of genetic test).
- Disease-causing (pathogenic) variations: changes in genes that cause a specific condition or disorder.
- Disease-risk variations: changes in genes that affect your risk of developing a specific condition or disorder.
- Unknown or new variations: changes in a gene where researchers do not know what the consequences are. Some changes will be new and we may not know if they contribute to the cause for a developmental difference or if they are normal variations.
- Positive (beneficial or helpful) variations: changes in genes that are helpful or protect a person (for example, one copy of the genetic change that causes sickle cell anemia protects a person against getting malaria). Because more research is done to learn about disease-causing genes, less is known about these kinds of beneficial genetic changes.
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