Xeroderma pigmentosum, resulting from mutations in the XPA gene, presents with hypersensitivity of the skin to ultraviolet light-induced freckle-like pigmentation changes and carcinogenesis. Patients present with extreme sunburn sensitivity and neurological degeneration.
Prevalence of XP in the West is approx. 1 in 500,000, but is much higher in Japan ( 1 in 20,000) and North Africa. Approx 20% of XP patients in the West are mutated in XPAΒΈ whereas in Japan, 54% are XPA, because of a founder effect. Inheritance is autosomal recessive.
XPA