PTEN Hamartoma Tumour Syndrome (PHTS, often shortened to PTEN) is a rare genetic condition. It is thought to affect around 200-300 people in the UK, although the number of patients identified is about 150 (as of July 2017). It is caused by an alteration of the genetic code in a gene called PTEN. This is an abbreviation of its full name: Phosphatase And Tensin Homolog. Alterations are sometimes passed down from parent to child, and sometimes the alteration is spontaneous (de novo).Sometimes referred to by its older classifications of Cowden Syndrome (CS) or Bannayan Riley Ruvulcaba Syndrome (BRRS), these syndromes (collection of symptoms) were first identified in the years before the development of genetic testing. Following the discovery that these different conditions were caused by the same gene, they were amalgamated under one name; PHTS or PTEN Hamartoma Tumour Syndrome.There is a wide range of symptoms associated with the condition which can vary considerably in severity. When recognised in children it can account for issues such as a big head (macrocephaly) , developmental delay, and autism. There is an increased risk of certain types of cancer in adults. People with the condition may have other problems affecting their skin including unusual pigmentation and wart-like lesions. Some people have fatty lumps called lipomas or overgrowth of blood vessels (arterio-venous malformations).If you are waiting for a diagnosis, are newly diagnosed, or just have suspicions, please take a look at our “New to PHTS” page.More detailed information can be found on our “On Diagnosis” page.There is no current treatment or cure. Patients are managed according to their symptoms. Doctors will discuss appropriate cancer surveillance for each person.Research is ongoing to try to understand the variability and to try to identify treatments and therapies. More information can be found on the PTEN Research Foundation website – www.ptenresearch.org.