Genetic testing of the PTEN gene can identify if someone has a mutation causing Cowden syndrome. There is a charge for these services when provided by clinically approved laboratories. These charges may or may not be covered by insurance and should be discussed with your doctor or genetic counselor.
The usual test for CS is called gene sequencing. In sequencing, the individual components (“letters”) of the PTEN gene are examined in detail looking for a mutation. This test is very accurate, but only about 40-80 percent of people meeting the criteria for CS have an identifiable mutation. This means that 20-60 percent of people who meet the criteria for CS will not have an identifiable mutation and will have a normal test result even though they do have CS. This could be due to a limitation in the test, and some labs offer additional testing to detect rare mutations missed by sequencing. It may also be possible, although this has not been proven, that CS could be cause by a mutation in another gene that has not been identified yet.
PTEN testing may also be available to you through a research study. Unlike clinical testing, research-based testing may take many months or years, but it is usually done without any cost to you. It may also provide information and results that are not available on a clinical basis. You may want to consider these issues as you decide whether you wish to pursue either clinical or research-based testing. Your physician and genetic counselor can help you if you are interested in participating in a research study.