Neurofibromatosis Type 1

Neurofibromatosis type 1 (NF1) is a complex neurocutaneous disorder also referred to as a “phakomatosis,” a term derived from the Greek phakos , meaning lentil or birthmark. Patients with NF1 often suffer from multiple lesions of diverse type, including hyperplasias, hypoplasias, hamartomas, and neoplasms, indicating that the NF1 gene product has dual functions in development and cell cycle control. Many NF1 lesions arise from tissues of neural crest origin, leading to the hypothesis that this syndrome results from maldevelopment of the neural crest. The term “neurocristopathy” is often used to describe NF1 and other disorders in which tissues of neural crest origin are affected (1 ). However, NF1 lesions also involve tissues arising from the neural tube, mesoderm, and endoderm, suggesting a widespread role for the NF1 gene product.