Have you ever noticed how hair color or eye color tend to run in families? Or how some families seem more likely to have cancer while others have multiple cases of heart disease or diabetes? These are examples of how genes can affect our lives.
Our genes are passed down from our parents. They make us who we are. But when it comes to diseases, most aren’t caused just by genes. In most cases, diseases and other health problems are caused by a combination of genes, our environment, and our lifestyle choices.
What are genes?
Genes are pieces of DNA inside each cell. They tell the cell what to do and when to grow and divide. They determine specific human characteristics, such as hair or eye color. Genes are passed down from each parent to their children. This is called heredity.
When do genes cause problems?
Most of the genes passed down from our parents are a perfect copy. But sometimes there are changes in some of the genes. These are called mutations. Every person has some mutations in their cells. Most are harmless and make no difference at all. But some can cause problems. When a mutation in a gene causes a health problem, that condition is called a genetic disorder.
How do genes cause genetic disorders?
There are different types of mutations that can cause or contribute to genetic disorders.
- Incorrect copies. This is when the copy of the gene that comes from one of your parents changes. These gene changes can make it more likely that you will develop diseases such as cancer or diabetes.
- Extra or too few copies. People are born with 2 copies of each gene (1 from each parent). But sometimes they are born with only 1 copy, or even 3 or more copies of the gene. This is called copy number variation. It can cause many conditions, including Parkinson’s disease and Alzheimer’s disease.
- Chromosome abnormalities. Humans have 23 pairs of chromosomes, which store our genes. Sometimes people are born with an extra chromosome, or they are missing one. Other times part of a chromosome breaks off and attaches to another chromosome. These types of changes affect larger numbers of genes. They can cause serious issues in a person, such as Trisomy 13 or Down syndrome.
Are mutations always passed down from our parents?
No, not all mutations are hereditary. Some happen during a person’s lifetime. These are called acquired mutations. Some acquired mutations are caused by elements in the environment. For example, ultraviolet radiation from the sun can change your genes. This can make you more likely to develop skin cancer.
Are there any genetic disorders that aren’t affected by environment or lifestyle?
Thousands of different diseases can be caused by gene mutations. There are a small number of diseases that are caused solely by a single gene change. Examples include Huntington disease (a degenerative disease of the nervous system), cystic fibrosis (a lung disease), and sickle cell anemia (a blood disorder). These diseases can’t be prevented with lifestyle choices. But they are rare.
Path to improved health
The good news is that in most cases, genes alone do not cause diseases. Diseases are most often caused by a combination of genes, environment, and lifestyle choices. So there are many things you can still do to prevent disease, even if you have the genes for it. You can’t change your genes, but you can change your behavior.
Here are some ways to get started:
- Eat a healthy diet. Eat more fruits and vegetables. Limit sugar, fat, and alcohol.
- Exercise regularly. Every little bit helps. Start slow and try to work up to at least 30 minutes of exercise 5 days a week.
- Don’t smoke. If you already smoke, talk to your doctor about quitting. Also try to avoid secondhand smoke.
- See your doctor. Get any medical treatment you need, such as controlling high blood pressure or having polyps removed. Get an annual check-up. Your doctor can monitor any conditions you have and screen you for any conditions you may be at risk for.
- Get a family history. Ask your family members about their health histories. Find out what diseases or conditions they have so you can tell your doctor. This will give him or her an idea of what to look out for.
Things to consider
Through our genes, we may be at higher risk for some diseases. Some gene mutations can increase our risk of developing diseases such as cancer, diabetes, or heart disease. But it is often our choices that determine whether we develop the disease. For example, you may have a mutated gene or combination of genes that makes you more likely to get cancer. If you smoke, you are greatly raising that risk, because smoking changes your genes, too. If you quit or choose not to smoke, you lower your risk. So our choices are very important factors when it comes to our bodies developing diseases. Live a healthy lifestyle and see your doctor regularly to reduce your risk of developing disease, regardless of what your genes are.
Questions to ask your doctor
- Is there anything in my family history that I need to watch out for?
- How does my environment affect whether I get a disease?
- What lifestyle choices can I make to keep from getting a disease?
- Should I get more screenings or check-ups since a disease runs in my family?
Copyright © American Academy of Family Physicians
This information provides a general overview and may not apply to everyone. Talk to your family doctor to find out if this information applies to you and to get more information on this subject.