Cowden syndrome

Cowden syndrome is an inherited disorder characterized by multiple tumor-like growths (called hamartomas) and an increased risk of certain cancers.

Almost everyone with this condition has hamartomas. These small, noncancerous 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. People with Cowden syndrome have an increased risk of developing several types of cancer, including cancers of the breast, thyroid, and uterus. Noncancerous breast and thyroid diseases are also common. Other signs and symptoms of Cowden syndrome can include an enlarged head; a rare, noncancerous brain tumor called Lhermitte-Duclos disease; and mental retardation.

Because Cowden syndrome can be difficult to diagnose, the exact prevalence is unknown; however, it probably occurs in at least 1 in 200,000 people.

Mutations in the PTEN gene cause Cowden syndrome.

PTEN is a tumor suppressor gene, which means it helps control the growth and division of cells. Inherited mutations in the PTEN gene have been found in about 80 percent of people with Cowden syndrome. These mutations prevent the PTEN protein from effectively regulating cell survival and division, which can lead to the formation of tumors. Cowden syndrome is one of several inherited diseases caused by mutations in the PTEN gene.

In the other 20 percent of Cowden syndrome cases, the cause is not yet known. Some of these cases may be caused by mutations in a region of DNA that regulates the activity of the PTEN gene.

This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene is sufficient to cause the disorder.

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.

You may find the following resources about Cowden syndrome helpful.

• NIH Publications - National Institutes of Health
  Genetics of Breast and Ovarian Cancer (National Cancer Institute)
• MedlinePlus - Health Information
  Health Topic: Cancer
• Educational resources - Information pages (2 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

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

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

autosomal ; autosomal dominant ; cancer ; DNA ; gene ; mental retardation ; mutation ; new mutation ; protein ; sign ; symptom ; thyroid ; tumor ; tumor suppressor gene

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