Health Topics
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A particular disorder might be described as “running in a family” if more than one person in the family has the condition. Some disorders that affect multiple family members are caused by gene variants (also known as mutations), which can be inherited (passed down from parent to child). Other conditions that appear to run in families are not caused by variants in single genes. Instead, environmental factors such as dietary habits, pollutants, or a combination of genetic and environmental factors are responsible for these disorders.
It is not always easy to determine whether a condition in a family is inherited. A genetics professional can use a person’s family health history (a record of health information about a person’s immediate and extended family) to help determine whether a disorder has a genetic component. He or she will ask about the health of people from several generations of the family, usually first-, second-, and third-degree relatives.
Degrees of relationship |
Examples |
|---|---|
First-degree relatives |
Parents, children, brothers, and sisters |
Second-degree relatives |
Grandparents, aunts and uncles, nieces and nephews, and grandchildren |
Third-degree relatives |
First cousins |
This condition affects members in each generation of a family.
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.