How is PHTS diagnosed?

A diagnosis of PHTS is made as a result of a genetic test showing an alteration in the PTEN gene.

PHTS associated syndromes

Before genetic testing was widely used, people were given a number of diagnoses depending on their particular combination of symptoms. Historically, the most common ones were Cowden syndrome (CS) and  Bannayan-Riley-Ruvalcaba syndrome (BRRS). Today, people with these syndromes who have a known PTEN mutation would be classed as having PHTS.  

Importantly, not all people with CS or BRRS necessarily have PHTS.  Some people, when tested, are found to not have a PTEN gene alteration, and some have an alteration in a different gene.  Also, some people with a diagnosis of one of these syndromes based on their symptoms have not had a genetic test, so it is not known if they have PHTS or not.

PHTS diagnosis pathway

PHTS is suspected if people have a combination of symptoms linked with the condition, or if they had a previous diagnosis of Cowden syndrome (CS), Bannayan-Riley-Ruvalcaba syndrome (BRRS) or other syndromes that have been associated with PHTS.

If this is the case, a doctor may recommend that a person has a genetic test to see if they carry a PTEN gene alteration, which confirms a diagnosis of PHTS. The exact number of symptoms required to prompt such a test varies, depending on whether anyone else in the family has or had PHTS, and the clinical guidelines used where the individual lives. Like many rare genetic conditions, it may take a while to find a doctor who is familiar enough with PHTS to understand what the pattern of symptoms could mean. This means that for some people it can take time before an accurate diagnosis is reached.

What does a genetic test involve?

A genetic test requires a sample of blood, from which DNA is extracted and analysed for gene alterations.

A doctor might recommend getting a single PTEN gene test if they are confident that an altered PTEN gene can explain the symptoms. If they are less sure, they may request a panel test that looks at several genes that might be responsible for the condition at once.

If neither of these tests reveals an altered gene, more comprehensive genetic tests might be considered.

Usually, an individual’s physician will refer them to a specialist genetic service for these tests. They may also recommend talking to a genetic counsellor. This is someone who can offer support and can fully explain the implications of the result for the individual and what it means for the rest of the family.

It can take anything from a few weeks to several months to receive the results of a genetic test. This depends on the specific test being done and the test provider.

For more information see:

Genetic Alliance UK: What is a genetic test

MedlinePlus: Genetic testing