Xeroderma Pigmentosum

XERODERMA PIGMENTOSUM
  • An autosomal recessive disorder of DNA repair
  • The most common defect - nucleotide excision repair (NER) enzymes are mutated.
  • It is characterized by photosensitivity, pigmentary changes, premature skin ageing, neoplasia
  • History - the child cries on exposure to light
  • Skin turns erythematous on exposure to sun
  • Development of freckles and lentiginosis on the exposed area of the body, such as the extensor aspect of arms, face and the neck are early signs
  • Later by adulthood squamous cell carcinoma, basal cell carcinoma, and malignant melanoma may form
Exam Question
  • Xeroderma pigmentation is caused due to a group of closely related abnormalities in Nucleotide excision repair.
  • Xeroderma pigmentosum is produced as a result of a defect in DNA Polymerase I and DNA ligase.
  • The primary defect in Xeroderma pigmentosa is formation of Thymidine dimers.
  • Xeroderma pigmentosum is a genodermal disease that can cause skin malignancy .
  • Cells cultured from patients with this disorder exhibit low activity for the nucleotide excision repair process. This autosomal recessive genetic disease includes marked sensitivity to sunlight (Ultra voilet light) with subsequent formation of multiple skin cancers and premature death, the disorder is Xeroderma pigmentosum.
  • Defective DNA repair is a/w Xeroderma pigmentosum.
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