Peutz-Jeghers Syndrome (PJS)

At a glance…

• Caused by a difference in the STK11 gene
• Polyps develop in the bowel and stomach
• Distinctive dark freckles may appear on lips, mouth, or fingers
• Increases risk of several cancers (bowel, pancreas, breast, ovarian)
• Each child of an affected parent has a 50% chance of inheriting PJS

What the syndrome is and what it means for you and your family

Peutz-Jeghers Syndrome (PJS) is a rare inherited condition that causes polyps in the stomach and bowel. Many people with PJS also develop small dark freckles on their lips, inside the mouth, or on their fingers.

People with PJS have an increased risk of several types of cancer (including bowel, pancreas, breast, and ovarian cancer), which is why lifelong monitoring is so important.

What symptoms to look out for

• Tummy pain or cramping
• Bleeding or anaemia
• Blockages in the bowel (especially in younger people)
• Dark freckles on lips, mouth, or fingers

About the gene differences

PJS is caused by a difference in the STK11 gene. This gene normally helps control cell growth. When it does not work properly, polyps and other growths can develop.

How it runs in families

PJS is usually inherited in an “autosomal dominant” way. This means:

• If one parent has PJS, each child has a 50% chance of inheriting it.
• Sometimes PJS appears for the first time in a family.

How it is diagnosed

• Colonoscopy or endoscopy showing hamartomatous polyps
• The presence of the typical dark freckles
• Genetic testing for the STK11 gene

Screening and treatment

• Regular bowel and stomach checks with endoscopy
• Monitoring for other cancers, depending on age and family history
• Checks for children starting at a young age if they are at risk

Possible surgery options

Polyps are often removed during colonoscopies. If polyps cause blockages or cannot be managed with camera procedures, surgery may be needed.

Health and lifestyle tips

• Keep all screening appointments — this is the best way to stay well
• Know your family history and share it with your care team
• Stay active and maintain a healthy diet
• If you are female, be aware of the need for breast and gynaecological checks

Planning a family

Genetic counselling can help you explore your options if you are planning a family. Testing before or during pregnancy may be offered.