Which of the following condition is associated with defective DNA repair?
High-Yield Explanation
Xeroderma pigmentosum (XP) is an autosomal recessive disease with sun sensitivity, photophobia, early onset of lentigines and freckling, and subsequent neoplastic changes on sun-exposed surfaces. There is cellular hypersensitivity to UV radiation and to ceain chemicals. Patients with XP have defects in DNA damage recognition or in the nucleotide excision and repair pathway. More than 10 different genes have been shown to cause the different forms of xeroderma pigmentosum. Ref: Kopp P., Jameson J.L. (2012). Chapter 61. Principles of Human Genetics. In D.L. Longo, A.S. Fauci, D.L. Kasper, S.L. Hauser, J.L. Jameson, J. Loscalzo (Eds), Harrison's Principles of Internal Medicine, 18e.