Cowden Syndrome

What is Cowden syndrome?

Cowden syndrome is a rare disorder characterized by multiple noncancerous, tumor-like growths called hamartomas and an increased risk of developing certain cancers.

Almost everyone with Cowden syndrome develops hamartomas. These growths are most commonly found on the skin and mucous membranes (such as the lining of the mouth and nose), but can also occur in the intestinal tract and other parts of the body. Abnormal growths on the skin and mucous membranes typically appear by a person's late twenties.

People with Cowden syndrome have an increased risk of developing several types of cancer, including cancers of the breast, thyroid, and the lining of the uterus (the endometrium). Noncancerous breast and thyroid diseases are also common. Other signs and symptoms of Cowden syndrome can include an enlarged head (macrocephaly); a rare, noncancerous brain tumor called Lhermitte-Duclos disease; and mental retardation.

How common is Cowden syndrome?

Researchers estimate that Cowden syndrome affects about 1 in 200,000 people; however, the exact prevalence of this condition is unknown because it can be difficult to diagnose.

What genes are related to Cowden syndrome?

Mutations in the PTEN gene cause Cowden syndrome.

PTEN is a tumor suppressor gene, which means that it normally prevents cells from growing and dividing too rapidly or in an uncontrolled way. Mutations in the PTEN gene have been identified in about 85 percent of people with Cowden syndrome. These mutations, which affect all of the body's cells, prevent the PTEN protein from effectively regulating cell survival and division. Uncontrolled cell division can lead to the formation of hamartomas and cancerous tumors.

The cause of the remaining Cowden syndrome cases is unknown. Mutations in a region of DNA that regulates the activity of the PTEN gene may be responsible for some cases of this condition.

Read more about the PTEN gene.

How do people inherit Cowden syndrome?

This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to increase the risk of developing noncancerous and cancerous tumors.

In some cases, an affected person inherits the mutation from one affected parent. Other cases may result from new mutations in the gene. These cases occur in people with no history of the disorder in their family.

Where can I find information about treatment for Cowden syndrome?

These resources address the management of Cowden syndrome and may include treatment providers.

• Gene Review

You might also find information on treatment of Cowden syndrome in Educational resources and Patient support.

Where can I find additional information about Cowden syndrome?

You may find the following resources about Cowden syndrome helpful. These materials are written for the general public.

• MedlinePlus - Health informationHealth Topic: Cancer
• Educational resources - Information pages (3 links)
• Patient support - For patients and families (3 links)

You may also be interested in these resources, which are designed for healthcare professionals and researchers.

• Gene Reviews - Clinical summary
• Gene Tests - DNA tests ordered by healthcare professionals
• ClinicalTrials.gov - Linking patients to medical research
• PubMed - Recent literature
• OMIM - Genetic disorder catalog

What other names do people use for Cowden syndrome?

• Cowden's disease
• Cowden's syndrome
• CS
• MHAM
• Multiple hamartoma syndrome

See How are genetic conditions and genes named? in the Handbook.

What if I still have specific questions about Cowden syndrome?

• See How can I find a genetics professional in my area? in the Handbook.
• Ask the Genetic and Rare Diseases Information Center.
• Submit your question to Ask the Geneticist.

Where can I find general information about genetic conditions?

The Handbook provides basic information about genetics in clear language.

• What does it mean if a disorder seems to run in my family?
• What are the different ways in which a genetic condition can be inherited?
• If a genetic disorder runs in my family, what are the chances that my children will have the condition?
• Why are some genetic conditions more common in particular ethnic groups?

These links provide additional genetics resources that may be useful.

• Genetics and health
• Resources for Patients and Families
• Resources for Health Professionals

What glossary definitions help with understanding Cowden syndrome?

autosomal ; autosomal dominant ; cancer ; cell ; cell division ; DNA ; endometrium ; gene ; hamartoma ; macrocephaly ; mental retardation ; mucous ; mucous membrane ; mutation ; new mutation ; prevalence ; protein ; sign ; symptom ; syndrome ; thyroid ; tumor ; tumor suppressor gene

You may find definitions for these and many other terms in the Genetics Home Reference Glossary.