Health Topics
Official websites use .gov
A
.gov website belongs to an official government
organization in the United States.
Secure .gov websites use HTTPS
A
lock (
) or https:// means you’ve safely connected to
the .gov website. Share sensitive information only on official,
secure websites.
Statistical data can provide general information about how common a condition is, how many people have the condition, or how likely it is that a person will develop the condition. Statistics are not personalized, but they do offer estimates based on groups of people. By taking into account a person's family history, medical history, and other factors, a genetics professional can help interpret the statistics and explain what they mean for an individual.
Some statistical terms are commonly used when describing genetic conditions and other disorders. These terms include the following:
|
Statistical term |
Description |
Examples |
|---|---|---|
|
Incidence |
The incidence of a gene variant (also called a gene mutation) or a genetic disorder is the number of people in a specified group who develop a variant or disorder during a particular time period. Incidence is often written in the form “1 in [a number]” or as a total number of a population. |
About 1 in 200,000 people in the United States are diagnosed with syndrome A each year. An estimated 15,000 people worldwide were diagnosed with syndrome B last year. |
|
Prevalence |
The prevalence of a gene variant or a genetic disorder is the total number of people in a specified group at a given time who are living with the variant or disorder. This term includes both newly diagnosed and pre-existing cases in people of any age. Prevalence is often written in the form “1 in [a number]” or as a total number of people who have a condition. |
Approximately 1 in 100,000 people in the United States have syndrome A at the present time. |
|
Mortality |
Mortality is the number of deaths from a particular disorder occurring in a specified group per year. Mortality is usually expressed as a total number of deaths. |
An estimated 12,000 people worldwide died from syndrome C in 2020. |
|
Lifetime risk |
Lifetime risk is the average risk of developing a particular disorder at some point during a lifetime. Lifetime risk is often written as a percentage or as “1 in [a number].” It is important to remember that the risk per year or per decade is much lower than the lifetime risk. In addition, other factors may increase or decrease a person's risk as compared with the average. |
Approximately 1 percent of people in the United States develop disorder D during their lifetimes. The lifetime risk of developing disorder D is 1 in 100. |
Topics in the Variants and Health chapter
- What is a gene variant and how do variants occur?
- How can gene variants affect health and development?
- 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?
- How are gene variants involved in evolution?
- What information can statistics provide about a genetic condition?
- How are genetic conditions and genes named?
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.