Although it is possible to inherit some types of chromosomal abnormalities, most chromosomal disorders (such as Down syndrome and Turner syndrome) are not passed from one generation to the next.
Some chromosomal conditions are caused by changes in the number of chromosomes. These changes are not inherited, but occur as random events during the formation of reproductive cells (eggs and sperm). An error in cell division called nondisjunction results in reproductive cells with an abnormal number of chromosomes. For example, a reproductive cell may accidentally gain or lose one copy of a chromosome. If one of these atypical reproductive cells contributes to the genetic makeup of a child, the child will have an extra or missing chromosome in each of the body’s cells.
Changes in chromosome structure can also cause chromosomal disorders. Some changes in chromosome structure can be inherited, while others occur as random accidents during the formation of reproductive cells or in early fetal development. Because the inheritance of these changes can be complex, people concerned about this type of chromosomal abnormality may want to talk with a genetics professional.
Some cancer cells also have changes in the number or structure of their chromosomes. Because these changes occur in somatic cells (cells other than eggs and sperm), they cannot be passed from one generation to the next.
Topics in the Inheriting Genetic Conditions chapter
- What does it mean if a disorder seems to run in my family?
- Why is it important to know my family health history?
- What are the different ways a genetic condition can be inherited?
- If a genetic disorder runs in my family, what are the chances that my children will have the condition?
- What are reduced penetrance and variable expressivity?
- What do geneticists mean by anticipation?
- What are genomic imprinting and uniparental disomy?
- Are chromosomal disorders inherited?
- Why are some genetic conditions more common in particular ethnic groups?
- What is heritability?
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.