Main Entry: xeroderma pig·men·to·sum

Pronunciation: \-ˌpig-mən-ˈtō-səm, -ˌmen-\

Function: noun

: a genetic condition inherited chiefly as a recessive autosomal trait that is caused by a defect in mechanisms that repair DNA mutations (as those caused by ultraviolet light) and is characterized by the development of pigment abnormalities and multiple skin cancers in body areas exposed to the sun—abbreviation XP