This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Molecular Genetics, Subject name: Biochemistry
[{'content': 'Xeroderma pigmentosum is caused due to abnormalities in: \nSelect and explain. \nA. A SOS repair, B. Nucleotide excision repair, C. Base excision repair, D. Mismatch repair', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. B. Nucleotide excision repaira. It is transmitted as autosomal recessive and DNA repair mechanism is defective. DNA damage is produced by UV irradiation especially thymine dimers, cannot be incised. Inborn deficiency of the enzyme "nicking endonuclease" is there.b. Clinical manifestations: produces blisters on the skin.c. Dry keratosis, hyperpigmentation and atrophy of skin.d. May produce corneal ulcers.', 'role': 'assistant'}]