Individuals with the disorder xeroderma pigmentosum are hypersensitive to sunlight, and mutations to the dna in their skin cells are left uncorrected. why are the mutations not corrected in individuals with this disorder?

People with xeroderma pigmentosum are extremely sensitive to UV light. this condition is caused by mutations affecting the nucleotide excision repair pathway, the genes involved, in the case of E. coli, are Uvr (A, B, C, D). mutants in genes are very sensitive to ultraviolet light, therefore, Uvr genes confer UV resistance, when this pathway doesn't work, thymine dimers and other forms of UV damage can't be repaired. People with xeroderma pigmentosum develop severe sunburns from just a few minutes in the sun, and about half will get skin cancer.