- AR
- ‘Moon child’
- Nucleotide excision repair (NER) gene mutation
- Rare Autosomal Recessive genetic disorder of DNA repair in which the ability to repair damage caused by ultraviolet (UV) light is deficient
Definition
- Autosomal Recessive disorder of DNA repair
- Impaired ability to repair UV damage
Incidence
- In USA: 1 per 250,000
- More common in Japanese
Aetiology
- Genetic defect
- Autosomal Recessive disorder of DNA repair
Clinical
- Severe sunburn after short sun exposure
- Freckles at an early age
- Multiple dark spots on the skin
- Thin, dry skin ± solar keratoses
- Eyes that are very sensitive to the sun
- Skin malignancies at a young age
Pathology
- Most common defect: nucleotide excision repair (NER) genes are mutated
- Unrepaired damage → Mutations
- When important genes mutated (e.g. p53 or oncogenes), cancer develops
- Skin malignancies:
- BCC, SCC, Melanoma → 1000 x increased risk
- No reliable investigation exists
- Prenatal Dx is possible by amniocentesis or chorionic villi sampling
Management
- Preventative - Avoid UV light
Prognosis / Natural Hx:
- Most common cause of death: Metastatic Melanoma or SCC
- < 40% survive beyond age 20
Follow-up
- 3 monthly review
- Genetic counselling for families
