What is xeroderma pigmentosum
Last updated: April 1, 2026
Key Facts
- Autosomal recessive genetic disorder affecting DNA nucleotide excision repair (NER) mechanisms
- Caused by mutations in genes responsible for repairing UV-induced DNA damage
- Affects approximately 1 in 250,000 to 1 million people worldwide
- Increases skin cancer risk by approximately 1,000 times compared to the general population
- Symptoms appear in childhood and include severe photosensitivity, freckling, and progressive skin damage
Overview
Xeroderma pigmentosum (XP) is a rare inherited disorder where the body cannot properly repair damage caused by ultraviolet (UV) radiation from the sun. People with XP have an extremely high risk of developing skin cancer and eye problems, even with minimal sun exposure. The condition typically appears in infancy or early childhood.
Genetic Basis
XP results from mutations in genes controlling nucleotide excision repair (NER), a critical DNA repair mechanism. Normally, skin cells detect and repair UV damage within hours. In XP patients, this repair system fails or functions poorly, allowing mutations to accumulate. The condition follows an autosomal recessive pattern, meaning an affected individual inherited defective genes from both parents.
Symptoms and Manifestations
Early symptoms typically appear by age two and include:
- Severe sunburn after minimal sun exposure
- Intense freckling and changes in skin pigmentation
- Dry skin (xerosis) and scaling
- Photophobia (extreme light sensitivity in eyes)
- Progressive vision problems and corneal damage
Cancer Risk and Complications
People with XP face approximately 1,000 times higher risk of melanoma and non-melanoma skin cancers compared to the general population. Many develop skin cancer by age 10. Beyond skin cancer, XP can cause eye damage, neurological deterioration in some cases, and severe quality-of-life impacts due to sun avoidance requirements.
Management and Treatment
While there is no cure, management focuses on prevention and early detection. Strategies include strict sun avoidance, protective clothing, high-SPF sunscreen, regular skin examinations, eye protection, and UV-blocking films on windows. Early cancer detection through frequent dermatology visits significantly improves outcomes. Some patients benefit from oral retinoids or experimental therapies to reduce cancer incidence.
Related Questions
What are the symptoms of xeroderma pigmentosum?
Symptoms include severe sunburn from brief sun exposure, excessive freckling and pigmentation changes, dry skin, eye sensitivity to light, vision problems, and progressive skin lesions. Symptoms typically appear in infancy or early childhood and worsen over time with sun exposure.
How is xeroderma pigmentosum diagnosed?
Diagnosis involves genetic testing to identify mutations in NER genes, along with clinical evaluation of skin changes and sun sensitivity. Doctors may use DNA repair tests measuring cellular response to UV damage. Prenatal genetic testing is available for at-risk families.
What is the life expectancy for xeroderma pigmentosum?
Life expectancy varies but is typically reduced due to early-onset cancers. Those who survive childhood cancer and adhere strictly to sun protection measures may live into adulthood. Average lifespan is generally in the 30s, though some individuals with mild forms live longer.