Xeroderma pigmentosum

Definition

Xeroderma pigmentosum (XP) is a rare genetic disorder characterized by extreme sensitivity to ultraviolet (UV) light, leading to skin damage and a significantly increased risk of skin cancer. This condition results from defects in the nucleotide excision repair (NER) pathway, which is responsible for repairing DNA damage caused by UV radiation, highlighting the critical role of effective DNA repair mechanisms in maintaining genomic integrity.

5 Must Know Facts For Your Next Test

1. Xeroderma pigmentosum is caused by mutations in genes responsible for the nucleotide excision repair pathway, with at least seven different XP genes identified.
2. Individuals with XP can develop severe sunburns after just a few minutes of UV exposure, making sun protection critical for their health.
3. The disorder has an autosomal recessive inheritance pattern, meaning that a person must inherit two copies of the mutated gene to exhibit symptoms.
4. There is a heightened risk of developing skin cancers, such as melanoma and squamous cell carcinoma, often at an early age due to accumulated UV-induced DNA damage.
5. Management of xeroderma pigmentosum includes rigorous sun protection strategies, regular dermatological check-ups, and possibly surgical intervention for any skin lesions.

Review Questions

• How does xeroderma pigmentosum illustrate the importance of DNA repair mechanisms in preventing cancer?
  • Xeroderma pigmentosum exemplifies the vital role of DNA repair mechanisms by demonstrating how defects in nucleotide excision repair lead to an inability to fix UV-induced DNA damage. This inability results in severe skin damage and a high incidence of skin cancers in affected individuals. The study of XP highlights how efficient DNA repair pathways are essential for maintaining cellular integrity and preventing carcinogenesis.
• What are the genetic implications of xeroderma pigmentosum regarding its inheritance pattern and mutation types?
  • Xeroderma pigmentosum is inherited in an autosomal recessive manner, meaning that both parents must carry a mutated gene for their child to be affected. This condition is caused by mutations in one of several XP genes that are integral to the nucleotide excision repair pathway. Understanding this inheritance pattern helps in genetic counseling and assessing risks for family members.
• Evaluate the challenges faced by individuals with xeroderma pigmentosum in terms of daily life and long-term health outcomes.
  • Individuals with xeroderma pigmentosum face significant challenges, including extreme sensitivity to sunlight which limits outdoor activities and requires strict sun protection measures. The constant risk of developing skin cancers necessitates regular medical surveillance and interventions, impacting their quality of life. Furthermore, the psychological burden associated with living with a visibly debilitating condition can lead to social anxiety and emotional distress, highlighting the need for comprehensive care that addresses both physical and mental health needs.

Related terms

Nucleotide Excision Repair: A DNA repair mechanism that removes a wide range of DNA lesions, including those caused by UV light, through the recognition and excision of damaged nucleotides.

UV Radiation: A type of electromagnetic radiation emitted by the sun, which can cause direct DNA damage and is a significant factor in the development of skin cancers.

Skin Cancer: A group of cancers that develop in the skin cells, often associated with excessive UV exposure and genetic predisposition, including conditions like xeroderma pigmentosum.