Gardner Syndrome

What causes Gardner syndrome

The APC gene is a tumor suppressor that normally controls cell growth in the bowel lining and other tissues. One faulty copy is inherited, and when the second copy is damaged in a cell, growth becomes uncontrolled, forming polyps and other growths.

It is inherited in an autosomal dominant pattern: each child of an affected parent has a 50% chance of inheriting it. About 25% of people have a new variant with no family history.

Gardner syndrome is now considered part of the spectrum of familial adenomatous polyposis rather than a separate disease. The term describes FAP with prominent features outside the colon.

Signs and symptoms

In the colon

• Hundreds to thousands of adenomatous polyps, typically appearing in the teenage years
• Often no symptoms at first
• Later: rectal bleeding, diarrhea, abdominal pain, anemia, and weight loss
• Without treatment, colorectal cancer usually develops by age 35 to 45

Outside the colon

Other cancers

• Duodenal and periampullary cancer: the second most common cause of cancer death in FAP after colon cancer is prevented
• Thyroid cancer: papillary type, more common in young women
• Stomach cancer
• Hepatoblastoma: a rare liver cancer in young children
• Brain tumors (medulloblastoma) occasionally

Diagnosis

• Colonoscopy showing 100 or more adenomas strongly suggests FAP. Attenuated forms have fewer polyps.
• Genetic testing for APC confirms the diagnosis and allows testing of family members.
• Examination and imaging for osteomas (dental X-rays may show jaw changes), cysts and desmoids.
• Eye examination for CHRPE.
• Upper endoscopy to look for duodenal and stomach polyps.

Management and treatment

Screening

For people with or at risk of FAP or Gardner syndrome, guidelines recommend:

• Colonoscopy or sigmoidoscopy every 1 to 2 years starting around age 10 to 12
• Upper endoscopy with a side-viewing scope, starting around age 20 to 25
• Thyroid ultrasound every 1 to 2 years from the late teens
• Liver ultrasound and alpha-fetoprotein in early childhood in some programs, for hepatoblastoma
• Examination for desmoid tumors, especially after surgery

Surgery

Removal of the colon (colectomy) is the main way to prevent colorectal cancer, usually in the late teens or early 20s, or sooner if polyps are many or advanced. Options include:

• Total colectomy with ileorectal anastomosis: keeps the rectum, which then needs regular checks
• Proctocolectomy with ileal pouch-anal anastomosis (IPAA): removes the colon and rectum and creates an internal pouch

Other treatments

• Removal of duodenal polyps endoscopically, and surgery for advanced duodenal disease
• Desmoid tumors: watchful waiting, anti-inflammatory and hormonal medicines, chemotherapy or targeted therapy, and sometimes surgery or radiotherapy
• Removal of troublesome cysts or osteomas
• Dental care for tooth abnormalities

Outlook

Without treatment, nearly everyone with Gardner syndrome develops colorectal cancer. With screening and preventive surgery, colon cancer deaths are largely prevented, and life expectancy has improved greatly. Desmoid tumors and duodenal cancer are now the main causes of serious illness, so lifelong follow-up matters.

Frequently asked questions

What is Gardner syndrome?

Gardner syndrome is an inherited condition, a form of familial adenomatous polyposis, caused by APC gene changes. It causes hundreds of colon polyps that almost always become cancer without treatment, plus bony growths, skin cysts, dental problems and desmoid tumors.

What is the difference between Gardner syndrome and FAP?

They are caused by the same gene and are now considered the same condition. Gardner syndrome is the name used when FAP comes with prominent features outside the colon, such as osteomas, skin cysts, dental abnormalities and desmoid tumors.

Is Gardner syndrome inherited?

Yes. It follows an autosomal dominant pattern, so each child of an affected parent has a 50% chance of inheriting it. About a quarter of cases are caused by a new gene change in the affected person.

What are the first signs of Gardner syndrome?

Early signs can include multiple skin cysts in childhood, hard bony lumps on the jaw or skull, extra or unerupted teeth, and pigmented spots in the retina. Colon polyps usually appear in the teenage years, often without symptoms.

How is Gardner syndrome treated?

Treatment focuses on preventing cancer: regular colonoscopy from childhood, preventive removal of the colon usually in the late teens or 20s, upper endoscopy and thyroid checks, and management of desmoid tumors and other growths.