Phelan-McDermid Syndrome (PMS) is caused by a deletion, or loss, of the terminal segment of chromosome 22. Also known as chromosome 22q13.3 deletion. Individuals with PMS have developmental delay. They often do not develop functional language and can have autism spectrum disorders. There is a wide range of severity of symptoms observed in people with PMS.There are almost 200 families who are diagnosed with PMS in the UK & Ireland, and just under 2000 registered worldwide. All people with PMS have difficulty communicating; many are non-verbal and have issues around cognitive development and mobility and most have low tone in their limbs. All people diagnosed with PMS need additional care to support their daily lives.The Phelan-McDermid Syndrome Foundation UK (PMSF UK) is a registered charity in the United Kingdom. PMSF UK is about providing a supportive inclusive community for those who have or know someone with Phelan-McDermid Syndrome (PMS). We can provide family days and get-togethers and some limited support for additional therapies, equipment or sibling support. Support is critical when you are caring for someone who has the syndrome.There is easy access to information on this website about PMS and we can put you in touch with local families who have a member with PMS. There are lots of useful links to other charities that can support you and your family when someone has been diagnosed with this syndrome.PMSF UK is a global partner with Phelan-McDermid Syndrome Foundation (PMSF) that has members across the world in over 43 countries. Although it is a rare disease it affects people across the globe and PMSF UK is part of bringing that community together.