The overall purpose of this descriptive NF1 Natural History study is to serve as an umbrella protocol for the ongoing NF1 clinical trials program to allow the longitudinal evaluation of individuals with NF1 for NF1 related tumor and non tumor manifestations irrespective whether they are currently enrolled on a treatment study or not, and to develop a better understanding of the biology of NF1 related manifestations. Following these patients longitudinally will allow investigators to develop a better understanding of the natural history of these manifestations, provide the basis for the development of endpoints for clinical trials and to potentially develop more effective treatments. NF1 manifestations, which will be followed longitudinally, include PN, MPNST, optic pathway tumors, dermal neurofibromas, NF1 associated pain, and neuropsychological, motor, and endocrine function. A comprehensive treatment plan and recommendations will be developed and communicated with the patient and primary caregivers.