XP = xeroderma pigmentosum:

The Facts (as of 2022)

  • XP is an autosomal recessive genetic condition (this means it has no bearing on whether you have X or Y chromosomes)
  • Both parents need at least one copy of the affected (carrier) gene as per figure 1; resulting in a 25% chance of a child having the condition 
  • There are 7 types (complementation groups) of XP; groups A-G plus a further XP-variant, XP-V
  • XP typically effects the skin, but certain patients also have problems with the central nervous system as well as the eyes ​and ears
  • People with XP are 10,000 times more susceptible to skin cancer than the general population
  • There are less than 200 people with XP in the UK and similarly low numbers all around the world

Effects of XP

Patients with XP lack fully functioning DNA repair mechanisms which means…

  • The skin of people with XP is susceptible to Ultraviolet (UV) light, primarily from the sun and certain types of artificial lighting
  • Photoprotection is vital – this means covering the skin from harmful sources of light
  • UV light comes in 3 forms: UVA, UVB & UBC:
  • UVA & UVB covers the spectrum of 290-400 nm (nanometres) and it is this range of light that must be avoided – this is present in daylight hours until nightfall irrespective of weather
  • UVC is the wavelength of 100-290 nm, however this is mostly absorbed by the atmosphere and ozone layer so presents minimal to no risk
  • At least 30% of XP patients suffer a degree of neurological impairment including hearing, sight and or central nervous system problems
  • There is no cure for this genetic condition, treatment relies on frequent checks focusing on:
    • photoprotection and removal of skin cancers 
    • neurological support and monitoring
    • education for friends, family and the wider community
  • Staying safe for people with XP requires a new lifestyle with lots of planning – the psychosocial impact of this condition should not be underestimated

Information about the National XP Clinic

at St Thomas' Hospital, London

The NHS funded Xeroderma Pigmentosum (XP) Multi-Disciplinary clinic was established in April 2010 to
​provide expert clinical care for patients thought to have or diagnosed with XP.

It provides Photodermatology, Dermatological Surgery, Neurology, Ophthalmology, Neuro- Psycology and Genetics advice about living with XP. It is based at the Rare Diseases Centre at St Thomas’ Hospital in London and diagnostic testing is conducted at the Genome Damage and Stability Centre at the University of Sussex and the Molecular Genetics Laboratory at Guy’s Hospital. The service has three clinical nurse specialists who provide outreach services for adults and children, visiting patients at their home, school and workplace. 

For further information please visit  https://www.guysandstthomas.nhs.uk/our-services/xeroderma-pigmentosum-xp which includes links to information about how to protect yourself from ultraviolet radiation (UV), using a UV meter, information about the need for vitamin D and information to give to schools.