MUTYH is a gene that normally helps repair damaged DNA. It’s sometimes also referred to as MYH.
If you inherit mutations, or changes, in this gene, it won’t function like it should.
Everyone has two copies of the MUTYH gene, one that they acquire from each of their parents. People with mutations in both copies of the gene have what’s known as MUTYH-associated polyposis syndrome (MAP).
If You Carry a MUTYH Mutation, What Cancers Are You at Risk For?
MAP can increase your risk for developing precancerous polyps (abnormal growths) and colorectal cancer. Some people with MAP develop hundreds of polyps. MAP may also raise a person’s odds of having thyroid cancer, kidney cancer, and other cancers. (1) People who inherit a single copy of a mutated MUTYH gene are at a slightly elevated risk for colon cancer. (2)
How Does MUTYH Increase Your Risk for Cancer?
Normally, the MUTYH gene gives instructions to make an enzyme called MYH glycosylase. This enzyme helps correct errors that are sometimes made when DNA is copied before cell division. A gene mutation affects the ability of cells to fix these mistakes. (3)
Can You Be Tested for MUTYH?
Yes, a genetic test is available to identify MUTYH mutations.
You’ll be asked to provide a blood or saliva sample that will be analyzed in a lab.
Your doctor might recommend genetic testing if someone in your family has an MUTYH mutation, you develop colorectal cancer, you have multiple polyps, or you have other risk factors.
It’s a good idea to meet with a genetic counselor before being tested. This professional can assess your family history and help you understand how the test works. (1)
Why Is It Important to Know if You Are at Risk for MUTYH?
Identifying an MUTYH mutation can provide you with information about your cancer risk. People with MAP have up to an 80 to 90 percent lifetime chance of developing colorectal cancer. (4)
It’s important to remember that you need to have a mutation in both copies of the gene to develop MAP.
If you have just one copy of a MUTYH gene mutation, you’re known as a “carrier.” You won’t have MAP, but you might be at slightly elevated risk for colon cancer.
What’s more, your children may be at risk for developing MAP if your partner is also a carrier. If both parents are carriers of a MUTYH mutation, each of their children has a 25 percent chance of inheriting two mutations. (2)
Studies show as many as 1 in every 100 people may carry a single mutation in the MUTYH gene. (2)
History of the MUTYH Gene: When Was It Discovered?
In 1998, scientists identified the mutY gene in E. coli bacteria. Then in 2002, MUTYH was discovered in a Welsh family with a history of polyps and colorectal cancer, according to a study. (5)
What Do You Do if You Test Positive for MUTYH?
If you test positive for a MUTYH mutation in both copies of the gene, your doctor will likely suggest that you have earlier and more frequent screening for colon cancer.
The American Society of Clinical Oncology recommends that people with MAP should have colonoscopies every one to two years, starting at age 25 to 30. (2)
You might also undergo upper endoscopies, ultrasounds, and other imaging procedures more often.