Testing BRCA Negative
Could it be Cowden Syndrome?
by Sue Friedman
If your family is BRCA negative could the unexplained cancers among relatives be a result of Cowden Syndrome? This inherited disorder is caused by a mutation in a gene called PTEN. It’s not always easy to diagnose a family with Cowden Syndrome because of the broad range of possible features .
People with Cowden Syndrome have increased risk for both benign (noncancerous) and cancerous growths. Types of cancers seen in families with Cowden Syndrome include breast cancer, thyroid cancer, and endometrial (uterine) cancer. Women who have a PTEN mutation may have a lifetime risk for breast cancer as high as 50 percent, and like individuals with BRCA mutations, premenopausal breast cancer (breast cancer diagnosed before age 50) may be more common. Women with Cowden Syndrome also have up to a 10 percent risk for developing uterine cancer. Men with the mutation may also be at elevated risk for male breast cancer. Both men and women with a PTEN mutation have a risk for thyroid cancer that may be as high as 10 percent.
Other less common cancers, including ovarian and pancreatic cancers, can also be seen in families with this syndrome. Because some cancers are common to both BRCA and Cowden Syndrome families, the family medical history may appear similar prior to specific identification by genetic testing.
Other signs may point to Cowden Syndrome within a family. Carriers of the PTEN mutation may have visible benign growths such as lipomas (fatty lumps), polyps, hamartomas (benign masses), and skin tags. They may also have increased incidence of goiter (benign growth of the thyroid), and other thyroid problems, fibrocystic breast changes, and intestinal polyps. Some individuals may have a larger than average head size, although this doesn’t always occur. Any one of these signs alone doesn’t necessarily point to Cowden Syndrome. Genetics experts combine physical exam results and family medical history, including cancer, to help determine if there may be a PTEN mutation in the family.
Like those who have a BRCA mutation, individuals with a PTEN mutation have a 50 percent chance of passing the gene mutation along to their children. Genetic testing can identify this syndrome; however, because of the complexity associated with diagnosis, families with an increased incidence of cancer should consult with a cancer genetics expert to determine if Cowden Syndrome may be the cause. Families who have the above cancers and who test negative for a BRCA mutation should also consult with genetics experts to determine if testing for a PTEN mutation may be appropriate.
Learn more about Cowden Syndrome in “Making Sense of Uninformative Negative Tests” at our Joining FORCEs conference.
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