Inheritance
- Autosomal recessive
- 1-2 per million in the US
Mutation
- Defects in nucleotide excision repair (NER)
- Endonuclease excises DNA containing damaged bases (ex. pyrimidine dymers causados pela radiação UV)
- Complementation groups (A-G) and one XP variant
- Different proteins in the NER pathway
- XP variants (XPC) post-replication repair (DNA polymerase-n)
Clinical presentation - marked photosensitivity
- Solar lentigines by age of 2
- Early onset of all major skin malignancies in 1st decade
- Ocular abnormalities
- Photophobia, keratitis, corneal opacification
- Neurologic abnormalities (except XPV)
- Developmental delay, SNHL, ataxia
- De Sanctis-Cacchione syndrome
- Mortality related to metastatic melanoma or invasive SCC
Treatment
- Extreme photoprotective measures
- Topical imiquimod
- Oral retinoids
- Sonidegib 200mg id 7d on 3sem off (doente em Espanha com muitos CBCs)
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