The different forms of neurofibromatosis.

In the last two decades our knowledge of the natural history, genetics and management of the different forms of neurofibromatosis has changed. Of the numerical classifications of neurofibromatosis proposed in the past, only neurofibromatosis type 1 (Nf1) and neurofibromatosis type 2 (Nf2) have been shown to be distinct at clinical and molecular levels. Mosaicism has been demonstrated both in patients with Nf1 and in patients with Nf2, and features of segmental or mosaic Nf1 and Nf2 have been defined. The outlying phenotypes and the molecular genetics of other, rarer, types of neurofibromatosis have been delineated: these are hereditary spinal neurofibromatosis, Schwannomatosis, familial intestinal neurofibromatosis, autosomal dominant "cafe-au-lait spots alone", autosomal dominant "neurofibromas alone", Watson syndrome, Noonan/neurofibromatosis syndrome and the so-called syndrome of multiple naevi, multiple schwannomas and multiple vaginal leiomyomas. In this article I will review the different forms of neurofibromatosis, focusing on those aspects that most commonly challenge the neurosurgeon.