PTEN hamartoma tumor syndrome (PTEN-HTS or PHTS, OMIM 158350, ORPHA:306498) is the collective term for a group of syndromes, including Cowden syndrome, adult Lhermitte-Duclos disease, Bannayan-Riley-Ruvalcaba syndrome, and Proteus -like syndrome, caused by germline mutations in the PTEN gene, located on 10q23.3. This evidence concerns the gene PTEN and Cowden disease.