Phakomatosis (from Greek "phakos" meaning "spot, lens", aka neuro-oculo-cutaneous syndromes, neurocutaneous disorders, mother's spot) are multisystem disorders that have characteristic CNS, ocular, and cutaneous lesions of variable severity. The skin and the brain have a common ectodermal origin, so there are many genetic and acquired diseases that affect both tissues. However, in some conditions, e.g. von Hippel-Lindau disease, ectodermal presentation is minimal.