Xeroderma pigmentosum complementation group B (XPB) is an extremely rare subtype of xeroderma pigmentosum (XP; see this term), a rare photodermatosis predisposing to skin cancers.
The disease has been described in less than 10 families.
Some XPB patients present with classic XP features of varying severity (photosensitivity of skin with burning and freckling, skin and eye tumors) and mild neurological abnormalities, while others combine classical XP features with systemic and neurological manifestations of Cockayne syndrome such as short stature, bilateral sensorineural hearing loss and hyperreflexia (XP/CS complex; see this term).
XPB is due to mutations in the XPB gene (ERCC3) (2q21), involved in the nucleotide excision repair (NER) system.
Transmission is autosomal recessive.
Last update: May 2011