The Genetics of Gardner Syndrome

Written by: Paul Arnold • Edited by: Paul Arnold
Published Oct 23, 2009

Gardner syndrome is a rare autosomal dominant genetic disorder characterised by skin and soft tissue tumours, and by multiple polyps on the colon and upper intestine.

Gardner Syndrome Genetics

Gardner syndrome is brought on by mutations in the APC gene found on chromosome 5. APC stands for adenomatous polyposis coli and it is a tumour suppressor. When the gene functions normally it codes for a protein that helps to control cell growth. But when it is mutated cell growth goes out of control and accelerates which leads to the formation of polyps (growths) and non cancerous tumours in other parts of the body i.e. sebaceous cysts on the skin and bone osteomas.

Gardner syndrome follows an autosomal dominant pattern of inheritance. This means that a person who has the condition has a 50% chance of passing it on to their children. A child will only need to inherit one defective gene from either parent to contract the disease.

The affected gene is the same one that causes Familial adenomatous polyposis (FAP) which can lead to an increased risk of colon cancer. In fact Gardner syndrome is considered to be a clinical subgroup of FAP.

History of Gardner Syndrome

Gardner syndrome was described by Eldon J.Gardner (1909-1989). In a paper that appeared in the second volume of The American Journal of Human Genetic (1950) he suggested that a dominant mutant gene causes polyposis of the large intestine. Although this had been well documented before Gardner went further in later publications by observing that people with polyposis of the large intestine also had multiple osteomas, sebaceous cysts and multiple fibromas.

Symptoms and Gardner Syndrome Eyes

There are no specific symptoms for Gardner syndrome - though if the intestinal polyps grow too large they can cause bleeding. People with the condition are at a higher risk of developing tumours in other parts of the body and some people will have excessive growth of pigmented tissue in the retina.

Polyp of sigmoid colon - image released under Creative Commons Attribution 2.5

click to enlarge

Polyps associated with this disease tend to appear in the early to mid teens, and almost everyone who has Gardner's syndrome will have polyps by the time they are 35. There can be more than 1,000 of these growths in some individuals. They are often discovered during an endoscopy which is being carried out for other reasons.

Many people with this rare condition will go on to develop cancer, with colon cancer typically occurring some 10-15 years after the onset of the polyps.

Treatments can include removal of the colon as a preventative measure, and managing symptoms of the disease as they arise.

As there is a strong genetic component to Gardner syndrome, close family members of a person with the condition are advised by doctors to undertake tests to see if they have abnormal growths. Though there is no cure at the moment, but an earlier diagnosis means that some complications may be prevented.