Final answer:
Xeroderma pigmentosum is a genetic disorder resulting from DNA-repair defects. People with this condition cannot repair UV-induced DNA damage, leading to a higher risk of skin cancer. The defective repair process causes distorted DNA structure.
Step-by-step explanation:
Xeroderma pigmentosum is a genetic disorder that results from DNA-repair defects. The condition causes individuals to be sensitive to UV light and exhibit atypical skin pigmentation. As a result, they also have a higher incidence of skin cancer compared to individuals without Xeroderma pigmentosum.
People with Xeroderma pigmentosum cannot employ the nucleotide excision repair mechanism, which is responsible for repairing UV-induced DNA damage. When these individuals are exposed to UV light, such as sunlight, thymine dimers are formed. Thymine dimers are abnormal formations of adjacent thymine molecules in the DNA strand. In normal individuals, nucleotide excision repair enzymes can excise and repair these dimers. However, in individuals with Xeroderma pigmentosum, the repair process is defective, leading to distorted DNA structure and a higher risk of contracting skin cancer.