<prompt> An 8 year-old girl in a developing country with significant corneal scarring and multiple cutaneous skin lesions in sun-exposed areas. Neuro-developmental delay had been present since 3 months of age.What is the probable diagnosis which is due to defective nucleotide excision repair?Werner syndrome WSXeroderma pigmentosum XPRothmund-Thomson syndromeBloom syndrome BS  <response>: Xeroderma pigmentosum is an example of defective DNA nucleotide excision repair. There is an inability to repair DNA pyrimidine dimers caused by UV exposure. The following image shows an eight-year-old girl with Xeroderma pigmentosum. Frontal image of the face, showing large hyperkeratotic lesions with some induration suspicious of actinic keratosis and early squamous cell carcinoma. Also numerous hyper-pigmented lentigos and xerosis on the entire front of the face. Reference: Harpers illustrated biochemistry 30th edition 