Xeroderma pigmentosum (XP) is characterized by sun sensitivity (severe sunburn with blistering, persistent erythema on minimal sun exposure, marked freckle-like pigmentation of the face before age two years), ocular involvement (photophobia, keratitis, atrophy of the skin of the lids), and a greatly increased risk of cutaneous neoplasms (basal cell carcinoma, squamous cell carcinoma, melanoma). Xeroderma Pigmentosum (XP) includes complementation groups A through G (XPA-XPG) and XP variant. Mutations in the following genes are associated with each XP group: XPA (XPA), ERCC3 (XPB), XPC (XPC), ERCC2 (XPD), DDB2 (XPE), ERCC4 (XPF), ERCC5 (XPG), and POLH (XP-Variant). Mutations in XPA and XPC account for about 50% of XP patients. XP is inherited in an autosomal recessive manner.
This laboratory performs Sanger sequencing of the XPA gene.