What is Peutz-Jeghers syndrome?
Peutz-Jeghers syndrome is a genetic condition that causes non-cancerous growths to develop in the digestive system. The growths, called hamartomatous polyps, usually grow in the small intestine. They can also grow in the stomach or large intestine. Sometimes they grow outside the digestive system and may appear in the kidneys, lungs, gall bladder, nasal passages, bladder or the tubes that connect the kidneys to the bladder (ureters).
People with Peutz-Jeghers syndrome often also have small, dark-colored spots that look like freckles on some parts of their skin. The spots usually appear during childhood and often fade as the person gets older. Most spots are on the lips, around and inside the mouth, near the eyes and nostrils, and around the anus. The spots may also occur on the hands and feet.
Having Peutz-Jeghers syndrome increases a person’s risk of developing the following types of cancers:
- Digestive system cancer (stomach, esophagus, small intestine, pancreas, colon, or rectum)
- Breast cancer (females)
- Uterine cancer (females)
- A rare type of cervical cancer (females)
- Lung cancer
- Tumors of the ovaries and testicles (can be cancerous or non-cancerous)
Because Peutz-Jeghers syndrome is hereditary, the condition can be passed from parents to children in a family. Peutz-Jeghers syndrome often varies in how severe it is, even among people in the same family. Some people may have many polyps and may develop cancer at a young age, while others may only develop a few polyps and may not develop cancer.
What causes Peutz-Jeghers syndrome?
Peutz-Jeghers syndrome is caused by changes in a gene known as STK11. Genes carry information telling cells within the body how to function. The STK11 gene is needed for cells to grow and divide properly.
Most people without Peutz-Jeghers syndrome carry two working copies of the STK11 gene in their cells. One copy is inherited from the mother and one from the father. Cells from people with Peutz-Jeghers syndrome carry one working copy of the STK11 gene in their cells and one copy that is changed. This change causes the STK11 gene to not work properly. It is called a mutation.
About half of children with Peutz-Jeghers syndrome have inherited the STK11 gene mutation from a parent. The other half of the children with Peutz-Jeghers syndrome are the first people in their families to have a STK11 gene mutation. These children have no history of the condition in their families. In these cases, the change either happened in an egg or sperm cell when the child was formed or in one of the child’s cells during pregnancy. These children are the first in their families to have Peutz-Jeghers syndrome.
No matter how they acquired the mutation, people with Peutz-Jeghers syndrome have a 50% (1 in 2) chance of passing it on to their children.
What is the cancer risk for people with Peutz-Jeghers syndrome?
People with Peutz-Jeghers syndrome have an 85% risk of developing cancer by 70 years of age. The risks for each type of cancer are shown in the table below:
Type of Cancer
Digestive system (stomach, esophagus, small intestine, pancreas, colon or rectum)
Uterine, cervical or ovarian (female)
What are other symptoms or physical findings seen in people with Peutz-Jeghers syndrome?
People with Peutz-Jeghers syndrome may have other medical issues. Not all people with Peutz-Jeghers syndrome will have all the symptoms or physical findings listed below.
The growth of polyps in the digestive system may cause the following:
- Bowel obstruction (blockage in the large or small intestine)
- Rectal prolapse (the wall of the rectum slides out of place, sometimes sticking out of the anus)
- Severe bleeding in the digestive system
- Anemia (too little oxygen in the blood), causing the person to feel tired
Tumors of the ovaries and testicles may cause the following:
- Puberty that happens at an unusually young age
- Irregular or heavy menstrual periods in women
- Growth of breasts in boys
- Unusually short height in boys
How are people with Peutz-Jeghers syndrome screened for tumors?
People with Peutz-Jeghers syndrome should be managed by a doctor who knows this condition well. Children with Peutz-Jeghers syndrome should have regular screenings to detect cancer as early as possible. The goal of screening is finding and treating cancer early to allow the best outcome for patients. Cancer screening should only be performed in a center with experience in taking care of people with Peutz-Jeghers syndrome. People with Peutz-Jeghers syndrome should carefully talk about the benefits and risks of cancer screening with a doctor who knows the condition well.
The following guidelines for cancer screening in children and young adults with Peutz-Jeghers syndrome are recommended:
- Yearly physical exams by a doctor who knows Peutz-Jeghers syndrome well.
- Stomach and intestinal cancer screening:
- Imaging of the small intestine (CT or MR enterography) beginning at age 8 to 10. The doctor will determine how often this should be repeated based on what is seen. The imaging should be repeated no later than age 18. After that, imaging should be repeated every 2–3 years or as recommended by the doctor.
- Upper endoscopy (using a small camera to see the inside lining of the upper part of the digestive tract) beginning in late teens and repeated every 2–3 years. Colonoscopy (using a small camera to see the inside lining of the colon) beginning in late teens and repeated every 2-3 years.
- Breast cancer screening:
- Breast self-exam beginning at age 18 and repeated every month.
- Breast exam by a doctor beginning at age 25 and repeated every 6 months.
- MRI imaging of the breasts and mammogram, alternating these two tests every six months beginning at age 25.
- Pancreatic cancer screening:
- MR imaging of the pancreas and bile ducts (MR cholangiopancreatography) beginning at age 30–35 and repeated every 1–2 years. An endoscopic ultrasound (combining endoscopy and ultrasound to let the doctor see the digestive tract) may be done instead of MR imaging.
- Uterus, ovary and cervix cancer screening:
- Exam by a gynecologist and Pap smear test beginning at age 18–20 and repeated every year.
- Consider transvaginal ultrasound (a test where a doctor uses ultrasound to see the uterus, cervix and ovaries) beginning at age 18–20 and repeated every year.
- Testicle cancer screening:
- Exam of the testicles beginning at age 10 and repeated every year.
- Ultrasound of the testicles, if recommended by the doctor.
- Yearly checkups with the person’s regular primary care doctor.
It is possible that recommended screenings may change over time as doctors learn more about Peutz-Jeghers syndrome. Parents should discuss all screening options for their child with a doctor who knows this syndrome well. Because it is a complex condition, it is very important that parents seek out an experienced doctor for their child.
How is genetic testing for Peutz-Jeghers syndrome done?
The doctor may suspect Peutz-Jeghers syndrome after looking at a person’s medical or family history. In most cases, a doctor or genetic counselor will ask questions about a person’s health and the health of other family members.
The genetic counselor or doctor will record which family members have developed tumors, what types of tumors and at what ages the tumors occurred. From this information they will create a family tree. Doctors and genetic counselors will look at the family tree to find out:
- If there are more tumors than normal,
- If tumors occurred at younger-than-expected ages, and
- If the types of tumors match up with what might be seen in those with Peutz-Jeghers syndrome.
If Peutz-Jeghers syndrome is suspected in a child or other family members, the doctor or genetic counselor will likely recommend genetic testing of the STK11 gene.
Diagnostic genetic testing
If the doctor or genetic counselor suspects that a person has Peutz-Jeghers syndrome, diagnostic testing may take place as follows:
- A blood sample is collected.
- DNA is isolated from the cells in the sample. A person’s genes are made of DNA.
- Both copies of the person’s STK11 gene are checked for possible changes. A genetic specialist compares the two copies of the person’s STK11 gene to normal copies of those genes. If there are differences, the specialist decides if they might cause a certain condition such as Peutz-Jeghers syndrome.
- If a mutation is found in the STK11 gene, the genetic counselor will work with the family in the following ways:
- To help the family understand the cancer risks of Peutz-Jeghers syndrome
- To find out if other family members should consider testing for the mutation
- To help with decisions about prenatal genetic testing
It is important to remember that genetic testing does not always find mutations in the STK11 genes for all people with Peutz-Jeghers syndrome. A person can still have Peutz-Jeghers syndrome even if no mutations are found in these genes. There may be other genes that are related to the condition that doctors do not yet know about.
Prenatal genetic testing
Parents may undergo prenatal testing to find out if the pregnancy is affected with a known STK11 gene mutation in the family. Testing may take place either before pregnancy occurs or during pregnancy.
People considering prenatal testing should work with a genetic counselor to review the pros and cons of the testing. The genetic counselor can also help parents consider how they wish to handle the results of the testing.
Testing that occurs before pregnancy—Testing that happens before pregnancy is called preimplantation genetic diagnosis (PGD). This special type of genetic testing is done along with in vitro fertilization (IVF). PGD offers a way to test embryos for a known STK11 gene mutation before placing them into the uterus.
Testing that occurs during pregnancy—Testing can be used to see if a pregnancy is affected with a known STK11 gene mutation. A doctor gathers cells from the pregnancy in one of two ways:
- Chorionic villus sampling (CVS)—during the first trimester (first three months)
- Amniocentesis—during the second trimester or later (last six months)
Collected tissue can be checked for the presence of the STK11 gene mutation identified in the family.
Both of these tests carry minor risks and should be discussed with an experienced doctor or genetic counselor.
Genetic testing for Peutz-Jeghers syndrome is a complex process. Those thinking about testing should take time to consider the benefits and risks. They should discuss the process with a genetic counselor before testing is done. If they choose testing, they should review the test results with the doctor or genetic counselor to be sure they understand the meaning of the results.
Sometimes children or adults with Peutz-Jeghers syndrome can feel sad, anxious or angry. Parents who pass on an STK11 gene mutation to one or more of their children can feel guilty. Some people with an STK11 gene mutation could have trouble getting disability coverage, life insurance or long-term care insurance in some states. More information about genetic discrimination can be found at www.ginahelp.org.
Are there other special health care needs for children with Peutz-Jeghers syndrome?
People of any age with Peutz-Jeghers syndrome have a higher risk of cancer. They should monitor their health and adopt healthful habits throughout life. It is important to continue to have regular physical checkups and screenings. That way, any cancer can be found early at the most treatable stage.
Other ideas to reduce the risk of cancer:
- Eat a healthful diet with lots of fruits and vegetables
- Get regular exercise
- Avoid smoking or using tobacco products
- Avoid secondhand smoke
People with Peutz-Jeghers syndrome should watch for signs or symptoms that could signal cancer:
- Unexplained weight loss
- Loss of appetite
- Pain in abdomen
- Blood in the stool or changes in bowel habits
- Aches, pains, lumps or swelling that cannot be explained
- Headaches or changes in vision or nerve function that do not go away
It is important to seek medical help if anything unusual appears.
The St. Jude Web site is designed for educational purposes only and is not engaged in rendering medical advice or professional services. The information provided through this site should not be used for diagnosing or treating a health problem or a disease. It is not a substitute for professional care. If you have or suspect you may have a health problem, you should consult your health care provider.